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W Sandy Lk Addn II Infra-SY211201 PROJECT NO. 24459 DECEMBER, 2021 GEOTECHNICAL INVESTIGATION OFFICE/WAREHOUSE NEC WEST SANDY LAKE ROAD AND S.H. 121 COPPELL, TEXAS Presented To: MC II DEVELOPMENT, LTD. DALLAS, TEXAS December 22, 2021 Project No. 24459 MC II Development, Ltd. 3811 Turtle Creek Boulevard, Suite 1460 Dallas, Texas 75219 ATTN: Mr. Richard Crow GEOTECHNICAL INVESTIGATION OFFICE/WAREHOUSE NEC WEST SANDY LAKE ROAD AND S.H. 121 COPPELL, TEXAS Gentlemen: Transmitted herewith are copies of the referenced report. Should you have any questions concerning our findings or if you desire additional information, do not hesitate to call. Sincerely, REED ENGINEERING GROUP, LTD. Registration Number F-3114 Kundan K. Pandey, Ph.D., P.E. Project Engineer KKP/apv copy submitted via e-mail only December 22, 2021 - i - TABLE OF CONTENTS PAGE INTRODUCTION.................................................................................................... 1 Project Description...................................................................................... 1 Authorization................................................................................................ 1 Purpose and Scope....................................................................................... 2 FIELD AND LABORATORY INVESTIGATIONS............................................ 2 General.......................................................................................................... 2 Field Investigation........................................................................................ 3 Laboratory Testing...................................................................................... 4 GENERAL SITE CONDITIONS........................................................................... 5 Physiography................................................................................................ 5 Geology......................................................................................................... 5 Stratigraphy................................................................................................. 6 Ground Water.............................................................................................. 7 Texas Health and Safety Code and TCEQ Comment.............................. 7 Seismic Site Classification........................................................................... 8 ANALYSIS AND RECOMMENDATIONS.......................................................... 8 Potential Vertical Movements..................................................................... 8 Foundation Design....................................................................................... 9 Grade Beams/Tilt-Wall Panels................................................................... 11 Floor Slab...................................................................................................... 12 Retaining Walls............................................................................................ 19 Earthwork, General..................................................................................... 22 Earthwork..................................................................................................... 23 Pavement....................................................................................................... 26 Construction Observation and Testing Frequency................................... 32 - ii - TABLE OF CONTENTS (Continued) ILLUSTRATIONS PLATE PLAN OF BORINGS............................................................................................... 1 BORING LOGS....................................................................................................... 2-16 KEYS TO TERMS AND SYMBOLS USED......................................................... 17&18 LABORATORY TEST RESULTS........................................................................ 19-24 ABSORPTION PRESSURE-SWELL TEST RESULTS..................................... 25-28 SPECIFICATIONS PAGE WATER INJECTION W/“SELECT” FILL CAP................................................ 1 WATER INJECTION W/”FLEXIBLE BASE” CAP.......................................... 1 WATER INJECTION W/LIME-MODIFIED CAP............................................. 1 Project No. 24459 - 1 - December 22, 2021 INTRODUCTION Project Description This report presents the results of a geotechnical investigation performed for the proposed office/warehouse building to be located on West Sandy Lake Road in Coppell, Texas. The general orientation of the building is shown on the Plan of Borings, Plate 1 of the report Illustrations. The project consists of construction of an approximate 130,030-square foot office/warehouse building on an approximate 9.01-acre site located at the northeast corner of West Sandy Lake Road and State Highway (S.H.) 121 in Coppell, Texas. Site paving for parking and drives is included in the project. Finished floor elevation is currently set at Elev. 520.75. The recommendations provided herein should be reviewed by this office if finished floor elevation is changed by more than one foot. This office should be provided with the latest site grading plan to allow for evaluation and modification of the recommendations, if necessary. Authorization This investigation was authorized by Mr. Richard L. Crow by signature of our Proposal No. 10- 32 on November 10, 2021. Project No. 24459 - 2 - December 22, 2021 Purpose and Scope The purpose of this investigation has been to evaluate the general subsurface conditions and provide recommendations for:  design of the foundation system;  floor slab;  lateral earth pressures for design of retaining walls;  pavement subgrade; and  site preparation and earthwork compaction criteria. The investigation has included drilling sample borings, performing laboratory testing, analyzing engineering and geologic data and developing geotechnical recommendations. The following sections present the methodology used in this investigation. Recommendations provided herein are site-specific and were developed for the project discussed in the report Introduction. Persons using this report for other than the intended purpose do so at their own risk. FIELD AND LABORATORY INVESTIGATIONS General The field and laboratory investigations have been conducted in accordance with applicable standards and procedures set forth in the 2021 Annual Book of ASTM Standards, Volumes 04.08 and 04.09, "Soil and Rock." These volumes should be consulted for information on specific test procedures. Project No. 24459 - 3 - December 22, 2021 Field Investigation Subsurface conditions were evaluated with a total of 15 soil borings drilled to depths of 6 to 31-1/2 feet below existing (November 2021) site grades. The locations of the borings are shown on Plate 1 of the report Illustrations. Borings were located in the field using a GPS (global positioning system) unit. The accuracy of this unit is estimated to be within plus or minus one meter. Borings were advanced between sampling intervals by means of a truck-mounted drilling rig equipped with continuous flight augers. Samples of cohesive soils were obtained with 3-inch diameter Shelby tubes (ASTM D1587). Cohesionless soils (sands and gravels) were sampled in conjunction with the Standard Penetration test (SPT) (ASTM 1586). Delayed water level observations were made in the open boreholes to evaluate ground water conditions. Borings were backfilled at completion of field operations. Sample depth, description of materials, field tests, water conditions and soil classification [Unified Soil Classification System (USCS), ASTM D2488] are presented on the Boring Logs, Plates 2 through 16. Keys to terms and symbols used on the logs are included as Plates 17 and 18. Elevations shown on the boring logs are based on the nearest one-foot interpolations of the grades shown on the grading plan provided by the client. Project No. 24459 - 4 - December 22, 2021 Laboratory Testing All samples were returned to the laboratory and visually logged in accordance with the USCS. The consistency of cohesive soils was evaluated by means of a pocket penetrometer. Results of the pocket penetrometer readings are presented on the boring logs. Laboratory tests were performed to evaluate index properties, confirm visual classification and evaluate the undrained shear strength of selected samples. Tests and ASTM designations are provided in Table 1. TABLE 1. TESTS CONDUCTED AND ASTM DESIGNATIONS Type of Test ASTM Designation Atterberg Limits D4318 Moisture Content D2216 Partial Gradation D1140 Soil Suction D5298 Unconfined Compression (Soil) D2166 The results of these tests are summarized on Plates 19 through 24. Project No. 24459 - 5 - December 22, 2021 The expansive characteristics of the upper soils and weathered shale were also evaluated by means of four absorption pressure-swell tests conducted in accordance with general procedures discussed by Johnson and Snethen1. Results of the swell tests are presented graphically on Plates 25 through 28. GENERAL SITE CONDITIONS Physiography The site is located at the northeast corner of West Sandy Lake Road and S. H. 121 in Coppell, Texas. The site is a moderately sloping undeveloped tract of land covered with grass and scattered trees. Based on the grading plan, site grades vary from approximate Elev. 509 to Elev. 522. Finished floor is set at Elev. 520.75. It is estimated approximately up to 2 feet of cut and 11 feet of fill will be required to achieve finished floor elevation. Geology The site is located within terraced alluvial soils overlying the Cretaceous Woodbine Formation. The Woodbine Formation typically consists of variably stratified silty and sandy clays, clay, silty and clayey sands, sand, sandstone and shale with occasional interbeds of lignite. 1 Johnson, L.D., & Snethen, D.R. (1978). "Prediction of Potential Heave of Swelling Soil." Geotechnical Testing Journal, ASTM 1 (3), 117-124. Project No. 24459 - 6 - December 22, 2021 Stratigraphy Subsurface conditions encountered in the borings consisted of alluvial soil overlying residual soil of the Cretaceous Woodbine Formation. The alluvial soil consisted of dark brown to brown, brownish-yellow, and gray, high to moderate plasticity (CH to CL) clay and sandy clay, and clayey sand. The alluvial soils were encountered to depths of 14 to 18 feet. Below depths of 14 to 18 feet, residual soil consisting of brown to brownish-yellow and reddish-yellow clayey sand, gravelly sand, and poorly graded fine sand was encountered. The deeper borings drilled within the building footprint were terminated within the dense to very dense sand and gravelly sand at depths of 29-1/2 to 31-1/2 feet. The dense to very dense sand and clayey sand represent the severely weathered to weathered sandstone. Based on the suction profiles, the upper soils were relatively dry to depths of 6 to 10 feet at the time of the field investigation (November 2021). The upper 10 to 15 feet of the subsurface soil is anticipated to be seasonally active. The suction profiles are provided in the following graph. Project No. 24459 - 7 - December 22, 2021 Ground Water A limited amount of ground water seepage was noted in some borings (Borings B-1 and B-6) at depths of 29 to 30 feet during drilling. Ground water was not noted in the open bore holes at completion of drilling. The remaining borings were noted dry during drilling and at the end of the day of drilling. Based on post-drilling water level observations, ground water was not present within the depths explored in November 2021. The depth to ground water will fluctuate with variations in seasonal and annual rainfall. Texas Health and Safety Code and TCEQ Comment Pursuant to the Texas Health and Safety Code, Chapter 361, §361.538 and 30 Texas Administrative Code 330, §330.953, Reed Engineering Group, Ltd. has performed appropriate soil tests as required by these regulations to demonstrate that the subject property does not Project No. 24459 - 8 - December 22, 2021 overlie a closed municipal solid waste landfill. The site observations and subsurface data do not indicate the presence of buried municipal solid waste at this site. Based on these data, development of this site should not require a Development Permit, as described in §361.532 and §§330.951-330.963, Subchapter T. Seismic Site Classification The site has been classified with respect to seismic design criteria contained in the 2015 International Building Code (IBC), Section 1613, and ASCE 7-10, Chapter 20. The criteria require characterization of the upper 100 feet of subsurface materials. Based on the ASCE 7- 10 criteria, the site is classified as Site Class C in accordance with Table 20.3-1. ANALYSIS AND RECOMMENDATIONS Potential Vertical Movements Potential Vertical Movements (PVM) were evaluated using an empirical procedure developed by McDowell2 and modified by the Texas Department of Transportation, TxDOT Test Method 124-E3 in conjunction with the soil suction and absorption pressure-swell tests. Based on the PVM calculations and past experience, potential movements are estimated to be on the order of two to four inches. Movement will primarily be associated with seasonal changes in soil moisture. 2 McDowell, C. "The Relation of Laboratory Testing to Design for Pavements and Structures on Expansive Soils" (1959). Quarterly of the Colorado School of Mines, Volume 54, No. 4, 127-153. 3 "Method for Determining the Potential Vertical Rise, PVR." (1978). Texas Department of Transportation, Test Method Tex-124-E. Project No. 24459 - 9 - December 22, 2021 Ground-supported improvements (i.e., sidewalks and paving) will move in response to changes in soil moisture. The movement will be observed as heave if the soils are dry at the time the pavement or sidewalk is constructed. The movement will be observed as settlement if the soils are moist at the time of construction. Generally, settlement will be limited to the outer perimeter (outer four to five feet) of larger slabs. Prudent watering during extended dry climatic periods can control settlement. Recommendations are provided to limit movement below the building; however, some movement of site paving and sidewalks should be anticipated. The estimated PVM is based on current grading plan and finished floor elevation at 520.75. If finished floor elevation is altered by more than one foot, this office should be consulted for additional analysis and recommendations. Foundation Design Foundation support for concentrated column loads should be provided by reinforced concrete, underreamed (belled) piers. The piers should be founded at Elev. 506.0 within the brown to brownish-yellow clay and sandy clay. Considering current finished floor at Elev. 520.75, piers should be founded at an approximate depth of 15 feet below finished floor elevation. Piers should be founded on top of the sand or clayey sand stratum if encountered above the recommended founding depth. Piers should be designed for an allowable bearing pressure of 6 kips per square foot (ksf) considering dead load and 9 ksf considering total (live plus dead) load, whichever governs. Project No. 24459 - 10 - December 22, 2021 Piers proportioned in accordance with the allowable bearing value will have a minimum factor of safety of three with respect to dead load and two with respect to total load, against a plunging or shear failure. The weight of the pier concrete below final grade may be neglected in determining foundation loads. Elastic settlement of properly constructed underreamed piers should be limited to approximately ½ inch. The recommended end bearing value is based on a minimum center-to-center pier spacing of two times the average bell diameter. If piers will be closer than two bell diameters, center-to- center, a reduction in the end bearing is recommended. This office should be contacted for specific recommendations. Piers will be subjected to uplift associated with swelling within the upper clays. The piers should contain reinforcing steel throughout the pier to resist the tensile uplift forces. Reinforcing requirements may be estimated based on an uplift pressure of 1.2 ksf acting over the top 6 feet of pier surface area. The recommended uplift value is considered a working load. Appropriate factors of safety should be applied in calculating the percent of reinforcement. "Mushrooming", or widening of the upper portion of the pier shaft, will significantly increase the uplift pressure from the upper clays. "Mushrooms" should be removed from the piers prior to backfill operations. Pier caps should not be used with the piers unless a minimum void of 6 inches (factor of safety of 1.5) is created below the portion of the cap extending beyond the shaft diameter. The void may be reduced to four inches if remedial earthwork is performed in accordance with the Floor Slab section. Project No. 24459 - 11 - December 22, 2021 Uplift resistance for underreamed piers will be provided by the weight of the soil overlying the bell and the dead load from the structure. A minimum bell-to-shaft diameter ratio of two to one (2:1) is recommended to resist uplift associated with swelling of the upper soils. A maximum bell-to-shaft diameter ratio of 3:1 is recommended to limit possible caving of the bells. Significant quantities of ground water were not encountered within the recommended founding depths of piers during the field investigation. The use of casing or dewatering of pier excavations should not be required if close coordination of drilling and concrete placement is performed. Pier excavations should be dry and free of deleterious materials prior to concrete placement. In no case should the pier shaft excavations remain open for more than four hours prior to concrete placement. Continuous observation of the pier construction by a representative of this office is recommended. Observation is recommended to confirm the bearing stratum and that the excavations are dry prior to placement of concrete. Grade Beams/Tilt-Wall Panels Grade beams or tilt-wall panels should be constructed with a minimum void of 6 inches (Factor of Safety of approximately 1.5) beneath them. A void is recommended to limit potential foundation movements associated with swelling of the underlying soils. The void may be reduced to four inches if remedial earthwork is performed in accordance with the Floor Slab section. Project No. 24459 - 12 - December 22, 2021 The void can be created below grade beams by use of wax-impregnated cardboard forms or beneath tilt panels by over-excavating the required void space prior to panel erection. Retainer boards along the outside of the grade beam or tilt-wall panel will not be necessary. Grade beams should be double-formed. Earth-forming of beams below ground is not recommended because of the inability to control the beam excavation width. Fill on the outside of perimeter grade beams and/or tilt walls should be placed in a controlled manner. Backfill should consist of site-excavated clays, or equal, placed and compacted in accordance with the Earthwork section. If bedding soils must be used adjacent to the perimeter of the building, the clay/bedding soil interface should be sloped to drain away from the building. Compaction criteria are included in the Earthwork section. Floor Slab Potential movements associated with heave from a dry condition to a moist condition are estimated to be on the order of two to four inches. Additional movement is possible if the clays become saturated, such as can happen from utility leaks and excessive ponding of water adjacent to the perimeter walls. Two types of floor systems are considered feasible; a suspended floor and a ground-supported (or "floating") slab. The suspended floor is considered the most expensive but does provide the highest degree of confidence that post-construction movement of the floor will not occur. If this alternative is desired, a minimum void of 8 inches (approximate F.S. of 2) is recommended between the soil and the lowest structural element of the floor system. For this alternative, Project No. 24459 - 13 - December 22, 2021 plumbing lines should be suspended a minimum of four inches above the underlying soils. Where plumbing lines transition into the soil, they must be free to move up to four inches without intercepting the structure or distressing plumbing joints. Use of a ground-supported floor is feasible, provided the risk of some post-construction floor movement is acceptable. The potential movement can be reduced by proper implementation (i.e., construction) of remedial earthwork recommended in the following paragraphs. The risk of the potential movement occurring can be reduced by implementation of positive grading of surface water away from the building and backfilling immediately adjacent to the structure with on-site clays. Several options and alternatives are provided in the following sections. The purpose of the alternatives is to provide optimum performance of ground-supported slabs while limiting unnecessary costs. This office can assist with optimization of the alternatives upon review of proposed finished grades. The most economical way of limiting the potential for post-construction floor movement, and the most positive from a design perspective, is to reduce the potential for heave-related movement prior to construction of the floor. This can be accomplished by either:  mechanically excavating the upper soils, mixing the soils with water, then recompacting the excavated soils at an elevated moisture in controlled lifts; or  preswelling via multiple passes of water pressure injection. Project No. 24459 - 14 - December 22, 2021 Of these two, the least expensive, most positive and easiest if performed properly, is to preswell via the injection process. Both options are presented in the following sections. At completion of either the injection process or excavation and recompaction process, a surface seal will be required to maintain the desired moisture. Three types of surface seals can be provided:  a minimum of 12 inches of "select" fill;  a minimum of 6 inches of flexible base; or  lime stabilization of the top 6 inches of soil with a minimum of 6 percent hydrated lime at completion of reworking or injection. Experience has shown comparable performance for each of the recommended surface treatments. The final selection should be based on cut and fill requirements. For example, if the site has a net import of fill, then the most economical surface seal consists of "select" fill or flexible base since imported fill will be required. If site earthwork is balanced or is a net export, then the most cost-effective alternative would consist of stabilizing the surface soils with lime. The specific recommendations and general procedures for each of the alternatives are presented in the following subsections. Recommendations relevant to both alternatives are presented in the Other Considerations subsection following the alternative discussions. Project No. 24459 - 15 - December 22, 2021 Excavation and Recompaction Option - An alternative method of pre-wetting the upper soils to reduce the potential for post-construction swell consists of excavation of the upper soil, mechanically mixing the soil with water, then recompaction of the excavated soil in controlled lifts. This method of pre-wetting the soils is not effective unless the water is uniformly blended with the soil. Simply wetting the surface of the soil will not achieve the required result. General procedures are as follows. 1. Strip vegetation and dispose of the organic materials in accordance with the project specifications. 2. Excavate to Elev. 512.0. Extend the footprint of the excavated areas a minimum of 5 feet beyond the general building lines and a minimum of 10 feet beyond entrances. The lateral extent of the treated areas should be reviewed by the owner and design team to address desired reduction of movement outside the structure and surface paving. 3. Scarify the exposed subgrade to a depth of six inches, water as necessary and recompact to the density and moisture recommended in the Earthwork section. 4. Compact site-excavated soils in lifts as outlined in the Earthwork section to the subgrade required for the desired moisture cap. Place and compact soils in accordance with recommendations in the Earthwork section.  Note: If insufficient on-site fill exists to achieve the proposed subgrade for the "select" fill or flexible base options, all imported fill for use below the building should consist of "select" fill, flexible base, or approved common fill. Balance on-site soils to provide a uniform thickness of the imported fill. 5. Place and compact the surface moisture barrier, consisting of either:  12 inches of "select" fill; or  6 inches of flexible base; or  stabilize the top 6 inches of recompacted soil with a minimum of 6 percent hydrated lime. Project No. 24459 - 16 - December 22, 2021 Placement recommendations for "select" fill and flexible base are included in the Earthwork section. Lime stabilization should be conducted in accordance with the Texas Department of Transportation (TxDOT) "Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges," 2014 Edition, Item 260. Lime-stabilized soils should be compacted to a minimum of 95 percent of Standard Proctor density, ASTM D698. Consideration should be given to benching the perimeter of the excavations, from the bottom up, at one horizontal to one vertical (1H:1V) to create a transition between reworked soils and non-reworked soils. This will decrease the potential for concentrated differential movement between treated and untreated areas. Pressure Injection Option - This option consists of performing cut and fill balance followed by injection, then providing a surface seal. The performance of an injected subgrade is dependent upon the quality of the workmanship. Therefore, water pressure injection is not recommended unless a representative of this office is present full-time to observe all injection operations. Procedures consist of the following. 1. Strip vegetation and dispose of the organic materials in accordance with the project specifications. All existing trees should be surveyed prior to start of site grading work. Tree stumps should be excavated to a minimum depth of five feet and removed from site. All tree roots larger than two inches in diameter should also be excavated and removed from the site. The excavated areas should be backfilled with on-site soils compacted in lifts as described in the Earthwork section. 2. Cut and fill balance with on-site soils to the subgrade required for the desired moisture cap. Place and compact soils in accordance with recommendations in the Earthwork section. Project No. 24459 - 17 - December 22, 2021  Note: If insufficient on-site fill exists to achieve the proposed subgrade for the "select" fill or flexible base options, all imported fill for use below the building should consist of "select" fill, flexible base, or approved common fill. Balance on-site soils to provide a uniform thickness of the imported fill. 3. Preswell the upper clays via pressure injection with water. Perform injections to Elev. 510.0. Guideline specifications for performance of the injection process are included in the report Specifications. Three guideline Specifications are included, one for each of the three surface treatment options. 4. Place and compact the surface moisture barrier, consisting of either:  12 inches of "select" fill; or  6 inches of flexible base; or  stabilize the top 6 inches of injected soil with a minimum of 6 percent hydrated lime. Placement recommendations for "select" fill and flexible base are included in the Earthwork section. Lime stabilization should be conducted in accordance with TxDOT "Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges," 2014 Edition, Item 260. Lime-stabilized soils should be compacted to a minimum of 95 percent of Standard Proctor density, ASTM D698. The actual number of injection passes required will be dependent upon the soil moisture conditions at the time of construction. For estimating purposes, and considering dry conditions at the time of construction, a minimum of four injection passes should be anticipated. The injected areas should be extended laterally a minimum of five feet beyond the general building lines. The injection footprint should be increased a minimum of 10 feet beyond the building at entrances to reduce the potential for differential movement between the structure Project No. 24459 - 18 - December 22, 2021 and sidewalks or entrance pavement. The lateral extent of the treated areas should be reviewed by the owner and design team to address desired reduction of movement outside the structure and surface paving. Other Considerations - The moisture caps should be placed within approximately seven working days following completion of either the injection process or the excavation and recompaction operations to limit moisture loss. Careful consideration should be given to the actual area treated with either of the two alternatives to reduce movement. The potential for post-construction heave will be reduced in the treated areas; however, areas left untreated will result in differential movement. In general, it is recommended the treated area extend beyond the building at entrances to reduce the potential for differential movement among the building, the sidewalk and entrance pavement or in areas where site paving is relatively flat because of drainage or ADA considerations. The lateral extent of the treated area should be reviewed by the owner and design to address desired reduction of movement outside the structure and surface paving. Potential post-construction floor movement associated with heave, considering a properly preswelled or reworked subgrade, is anticipated to be on the order of one inch. Additional movement is possible if the clays become saturated, such as can happen from utility leaks and excessive ponding of water adjacent to the perimeter walls. Positive drainage of water away from the structure must be provided and maintained after construction. Architectural detailing of interior finishes should allow for approximately one inch of differential floor movement. Project No. 24459 - 19 - December 22, 2021 A minimum 10-mil thick polyethylene sheet is recommended below the floor to limit migration of moisture through the slab from the underlying soils. This is of particular importance below sections of the floor covered with carpeting, paint or tile. Penetrations and lapped joints should be sealed with a waterproof tape. Ground-supported floors over expansive soils may be subject to settlement if the underlying clays dry during the life of the structure. Natural desiccation will be limited to the outer four to five feet along the perimeter where surface pavement does not abut the structure. However, roots from trees and shrubs can grow below the structure and increase the zone of desiccation. This process typically requires 8 to 10 years to develop. An effective means of limiting plant root growth is construction of a vertical moisture barrier adjacent to the foundation or extension of paving to the perimeter of the building. If utilized, the barrier should consist of a minimum six-inch wide, five-foot deep lean concrete wall, or other suitable material. Trees and shrubs should be planted outside the barrier. Retaining Walls Lateral earth pressures against retaining walls will be a function of the backfill within the "active zone" of earth pressure. The “active zone” is the wedge of soil defined by the surface of the wall and a plane inclined 45 from the vertical passing through the base of the wall (or the base of the heel for a cantilevered wall). Project No. 24459 - 20 - December 22, 2021 Considering backfill using site-excavated materials, lateral earth pressures can be estimated based on an equivalent fluid pressure of 65 pounds per cubic foot (pcf) for active conditions, or 80 pcf for at-rest conditions. Rotation, or lateral movement on the top of the wall, equal to 0.02 times the height of the wall will be necessary for on-site soil backfill for the “active” condition. Alternatively, imported "select" fill may be used as backfill in the active zone. Considering "select" fill, lateral earth pressures can be estimated based on an equivalent fluid pressure of 40 pcf, active conditions, or 60 pcf at-rest conditions. Lateral movement of the top of the wall equal to 0.001 times the height of the wall will be necessary for the "active" pressure condition for "select" fill backfill. The lateral earth pressures are applicable for horizontal surface grades and non-surcharged, drained conditions. A drainage system should be installed behind the base of the retaining walls to limit development of hydrostatic pressure. The drainage system should consist, as a minimum, of 12-inch by 12-inch pocket drains spaced 10 feet on-center, installed near the base of the wall. Fill in the pocket drains should consist of durable crushed stone such as ASTM C33, Size 67 or coarser, wrapped in filter fabric (Mirafi 140N or equivalent). Backfill around the gravel drain should consist of site-excavated soils or "select” fill. A compacted clay cap is recommended within the upper two feet of the surface to limit surface-water infiltration behind the walls. Retaining walls may be founded on spread or continuous footings placed a minimum of 18 inches into undisturbed, on-site soils or compacted and tested fill. Footings should be proportioned for a maximum bearing pressure of 3,000 pounds per square foot (psf). Project No. 24459 - 21 - December 22, 2021 Movement of the footings and walls should be anticipated. Flexible walls are recommended. Solid concrete walls should be battered into the soil to limit outward rotational movement caused by differential footing movement. Passive resistance to lateral movement can be estimated based on an equivalent fluid pressure of 300 pcf for on-site materials. This value is applicable for footings founded on undisturbed, on-site soils or compacted and tested fill. In addition to passive resistance, a coefficient of friction between the base of the footing and the underlying soil equal to 0.35 may be used. The lateral earth pressure values do not incorporate specific factors of safety. If applicable, factors of safety should be integrated into the structural design of the wall. Earth slopes up to a height of eight feet should be graded at 4H:1V or flatter. Earth slopes greater than eight feet in height should be evaluated for global stability. This also applies to slopes combined with retaining walls that have a combined height in excess of eight feet. Global stability analysis was not within the scope of the present investigation. This office can assist in the preliminary global stability analysis if desired. Final global stability analysis is typically performed by the wall designer. All constructed slopes should be vegetated as soon as possible. Use of erosion control fabric is recommended during vegetation of the slopes. Project No. 24459 - 22 - December 22, 2021 The recommendations above are applicable for retaining walls that are not subject to inundation by water. Modification of the recommendations may be necessary for wet applications (such as detention ponds and water features). This office should be provided with grading plans and wall layouts to review for any necessary modifications to the recommendations for wet applications. Earthwork, General Proper compaction of soil requires both the correct moisture content and “compactive effort” or energy. The compactive effort, or energy, imparted into the soil by the equipment used for compaction, has to be compatible with the lift thickness. The lighter the equipment (lower contact pressure), the thinner the loose lift of soil has to be to achieve adequate compaction. If the lift of soil is too thick for the energy (compactive effort) exerted by the equipment, insufficient energy will be transferred through the full lift thickness, resulting in a lens of loose, settlement-prone soil at the bottom of the lift. For example, if track-mounted equipment such as a “dozer” is used for compaction, the thickness of lift will vary with the track contact pressure. For a Caterpillar D-6, with a contact pressure of approximately 1,000 psf, a maximum loose lift thickness of 6 inches (compacted lift of 4 inches) is needed to achieve compaction. For a Caterpillar D-10, with a contact pressure of approximately 3,000 psf, a maximum loose lift thickness of 8 inches (compacted lift of 6 inches) is needed to achieve compaction. Project No. 24459 - 23 - December 22, 2021 If the upper five to six inches of an excessively thick lift is well compacted, it can meet density, and therefore the loose, relatively thin lens at the bottom of the lift will not be detected by density testing resulting in the potential for settlement of under-compacted lenses. Accurately determining lift thickness is virtually impossible after the fact in large-scale mass earthwork operations, and can only be controlled by the earthwork contractor by “experience”. Alternatively, if the earthwork contractor’s field personnel do not have sufficient experience, a surveyor would need to be hired to accurately survey each lift to evaluate if excessive lifts are being placed. For equipment with a relatively light contact pressure (any type of equipment with a contact pressure of less than approximately 2,000 psf), there is virtually no “factor of safety” relative to the lift thickness. It is therefore recommended that, if track-mounted equipment is used for compaction, equipment with a minimum contact pressure of 2,500 psf be specified for mass earthwork operations. Earthwork All vegetation and topsoil containing organic material should be cleared and grubbed at the beginning of earthwork construction. Areas of the site that will underlie fill or within the building should be scarified to a depth of 6 inches and recompacted to a minimum of 95 percent and a maximum of 100 percent of the maximum density, as determined by ASTM D698, "Standard Proctor". The moisture content should range from +1 to +5 percentage points above optimum. Project No. 24459 - 24 - December 22, 2021 It is recommended that one-point swell tests at a pressure of 450 psf be performed on laboratory samples compacted to the above recommended density and moisture. If test results indicate that the swell will exceed one percent, the field moisture should be adjusted to limit the potential for swell to less than one percent. Site-excavated soils should be placed in maximum eight-inch loose lifts (note, loose lift thickness must be compatible with the compaction equipment) and compacted to the moisture and density requirements outlined above. The soils should be uniformly blended with water to achieve the required moisture content. The final 6 inches of subgrade below pavement should be compacted to a minimum of 95 percent of Standard Proctor, at or above optimum moisture. All tree stumps within the building and paving areas should be excavated to a minimum depth of five feet and removed from the site. Tree roots larger than two inches in diameter should also be excavated and removed from the site. The excavated areas should be backfill with on- site soils as described above. Proper backfilling around the building perimeter will reduce the potential for water seepage beneath the structures. Fill against the perimeter of the foundations should consist of site- excavated clays, or equal, placed and compacted in accordance with the recommendations outlined above. Project No. 24459 - 25 - December 22, 2021 "Select" fill is defined as uniformly blended clayey sand with a Plasticity Index (PI) of between 4 and 15. “Select” fill should be placed in maximum 8-inch loose lifts and compacted to at least 95 percent of the Standard Proctor density, at a moisture content between -2 to +3 percentage points of optimum moisture. Flexible base for use below the building slabs is defined as crushed stone or crushed concrete meeting the requirements of the 2014 Edition of TxDOT, “Standard Specifications for Construction and Maintenance of Highways, Streets and Bridges”, Item 247 Grade 1 or 2, Type D or better. Flexible base should be compacted to a minimum of 95 percent of Standard Proctor density, at a moisture content between -2 to +3 percentage points of optimum moisture. Lime stabilization should be conducted in accordance with TxDOT "Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges," 2014 Edition, Item 260. Lime-stabilized soils should be compacted to a minimum of 95 percent of Standard Proctor density, ASTM D698 at or above optimum moisture content. The moisture cap should be placed within approximately seven working days over the injected or reworked subgrade to limit moisture loss within the underlying soils. Crushed stone utilized for the drainage system behind retaining walls should consist of durable gravel meeting ASTM C33 Size 67 or coarser. Gravel should be placed in maximum 8-inch loose lifts and compacted to a minimum of 60 percent of the relative density as determined by ASTM D4254. Project No. 24459 - 26 - December 22, 2021 Pavement As stated above, the PVR on this site is two to four inches. If this magnitude of potential movement of the pavement is acceptable, no remedial earthwork will be necessary. If it is not acceptable, it is recommended that subgrade modification be performed. This office can assist with different depths of subgrade modification versus PVR, if desired. If subgrade modification is limited to the building envelopes, site grading should account for the potential movements beyond the treated area of the building. The specific pavement section will be dependent upon: 1. traffic loads and frequency; 2. pavement type and strength; 3. desired pavement life; and 4. strength and condition of the subgrade. Information regarding the specific traffic loads and frequency is not available. Therefore, analysis was performed for a range of traffic conditions, and design thickness versus traffic load diagrams were developed. The pavement designer, typically the civil engineer, should review the anticipated traffic with the building owner or end user. If the anticipated traffic will vary from the stated values in the following paragraphs, this office can provide alternative sections upon request. Project No. 24459 - 27 - December 22, 2021 The pavement type has been identified as concrete. Analysis was performed for both 3,000 pounds per square inch (psi) and 4,000-psi compressive strength concrete. A 20-year life was used for the analysis. Total pavement life was based on a six-day week. Analysis was performed in accordance with procedures developed by the American Association of State Highway and Transportation Officials (AASHTO). The upper surface soils consist of CH clays. When these soils are moist, they are relatively soft. For purposes of pavement analysis, the subgrade was assumed to be recompacted in accordance with the density and moisture recommendations in the Earthwork section and in a moist condition. An effective modulus of subgrade reaction, k, of 100 pounds per cubic inch (pci) was used for the analysis. The effective k value of the subgrade can be increased to 200 pci by stabilization of the upper 6 inches with a minimum of 6 percent hydrated lime. Lime should be placed and compacted in accordance with Item 260 of the current edition of TxDOT "Standard Specifications for Construction of Highways, Street and Bridges." The lime-stabilized subgrade should be compacted to a minimum of 95 percent Modified Proctor, ASTM D1557, at or above optimum moisture. Generally, it is more cost-effective to increase the pavement thickness than to lime-stabilize the subgrade. However, stabilization does provide an all-weather working platform for the contractor, and this may be beneficial from a construction perspective, especially if construction will occur during the wetter part of the year. Stabilization is also recommended if the traffic speed exceeds 30 miles per hour (mph). Project No. 24459 - 28 - December 22, 2021 Considering the above discussion, analysis was made for both unlimited repetitions of cars and light trucks and for multiple repetitions of loaded tractor trailers. Analysis indicates a pavement thickness of 4.5 inches of 3,000-psi concrete will be adequate for car and light truck traffic. A minimum five-inch section over a scarified and recompacted subgrade is recommended. Pavements subject to multiple repetitions of tractor-trailer traffic were analyzed using both 3,000- and 4,000-psi concrete. Trailers were assumed to be loaded to the maximum allowable weight, 80 kips, consisting of two sets of tandem axles loaded to 32 kips and one 16-kip axle. Recommended sections for various rates of truck traffic, based on number of repetitions per day for a 6-day week, are provided in the following tables considering a subgrade k value of 100 pci and 200 pci. The sections are based on 20-year service life. The values presented in Tables 2 through 5 below represent the minimum thickness of the pavement section that should be constructed for the corresponding traffic volume. Allowance for variations that can occur during construction should be incorporated in the plan. Project No. 24459 - 29 - December 22, 2021 TABLE 2. (K=100 PCI) NUMBER OF TRUCK REPETITIONS VS. PAVEMENT THICKNESS 3,000-PSI COMPRESSIVE STRENGTH Pavement Thickness (inches) No. of Repetitions (per day) 6 (minimum recommended for fire lanes) 12 7 30 8 65 9 140 10 280 TABLE 3. (K=100 PCI) NUMBER OF TRUCK REPETITIONS VS. PAVEMENT THICKNESS 4,000-PSI COMPRESSIVE STRENGTH Pavement Thickness (inches) No. of Repetitions (per day) 6 18 7 45 8 105 9 220 10 440 Project No. 24459 - 30 - December 22, 2021 TABLE 4. (K=200 PCI, LIME-STABILIZED SUBGRADE) NUMBER OF TRUCK REPETITIONS VS. PAVEMENT THICKNESS 3,000-PSI COMPRESSIVE STRENGTH Pavement Thickness (inches) No. of Repetitions (per day) 6 (minimum recommended for fire lanes) 18 7 42 8 90 9 185 10 350 TABLE 5. (K=200 PCI, LIME-STABILIZED SUBGRADE) NUMBER OF TRUCK REPETITIONS VS. PAVEMENT THICKNESS 4,000-PSI COMPRESSIVE STRENGTH Pavement Thickness (inches) No. of Repetitions (per day) 6 28 7 65 8 140 9 280 10 550 The values are based on Terminal Serviceability Index (pt) of 2.0, Overall Standard Deviation (Sd) of 0.35, Reliability (R) of 90 percent, Load Transfer Coefficient (J) of 3.2, and Drainage Coefficient (Cd) of 1.0. Project No. 24459 - 31 - December 22, 2021 Analysis of Tables 2 and 3 indicates an approximate 50 to 57 percent increase in the number of truck repetitions can be obtained by increasing the concrete strength from 3,000 psi to 4,000 psi. An increase of approximately 100 to 150 percent is realized by increasing the thickness of the pavement by 1 inch. Analysis of the allowable repetitions was also performed considering a stabilized subgrade (Tables 4 and 5). For any given pavement thickness and strength of concrete, an increase in the number of repetitions equal to 25 to 50 percent of the non-stabilized repetitions is realized. Considering the relative costs associated with stabilizing the subgrade, a greater increase in repetitions (i.e., pavement life) is realized by increasing the pavement thickness or strength versus stabilization of the subgrade. Pavements should be lightly reinforced if shrinkage crack control is desired. Reinforcing for 5- and 6-inch pavements should consist of the equivalent of #3 bars (metric #10) at 24 inches on- center, and 18 inches on-center for pavements of 7-inch thickness or greater. Pavement sections should be saw-cut at an approximate spacing in feet of 2.5 to 3 times the pavement thickness expressed in inches, not to exceed a maximum spacing of 20 feet. (For example, a 5-inch pavement should be saw-cut in approximate 12.5- to 15-foot squares.) The actual joint pattern should be carefully designed to avoid irregular shapes. Load transfer Project No. 24459 - 32 - December 22, 2021 devices at transverse joints should be provided as necessary. Recommended jointing techniques are discussed in detail in "Guide for Design and Construction of Concrete Parking Lots," published by the American Concrete Institute4. At the truck courts where the pavement abuts the building, it is recommended that the last six inches of pavement be swept up three to four inches to decrease the chances of water ponding adjacent to the building. The above sections are based on the stated analysis and traffic conditions. The pavement designer, typically the civil engineer, should review the anticipated traffic with the building owner or end user. If the anticipated traffic will vary from the stated values above, this office can provide alternative sections upon request. Additional thickness or subgrade stabilization may be required to meet the City of Coppell development code. Construction Observation and Testing Frequency It is recommended the following items (as a minimum) be observed and tested by a representative of this office during construction. Observation:  Fill placement and compaction.  Pressure-injection operations.  Pier construction and concrete placement. 4 "Guide for Design and Construction of Concrete Parking Lots" (1987). American Concrete Institute, Publication MSP 34, Silver Spring, MD. Project No. 24459 - 33 - December 22, 2021 Testing:  Earthwork  One test per 5,000 square feet per lift within fills below the building.  One test per 10,000 square feet per lift within fills in the paving area.  One test per 150 linear feet per lift in utility and grade beam backfill.  One test per 100 linear feet per lift in retaining wall backfill.  Post-injection borings, one boring per 10,000 square feet of injected area. The purpose of the recommended observation and testing is to confirm the proper foundation bearing stratum and the earthwork and building pad construction procedures. ILLUSTRATIONS B-13B-15B-14B-11B-10B-5B-7B-8B-6B-4B-3B-2B-9B-1B-12REED ENGINEERINGGROUPOffice / WarehouseNEC West Sandy Lake Road and S.H. 121Coppell, TexasProject No. 24459PLATE 1APLAN OF BORINGS0 50' 100'200' Seepage during drilling 50 Blows = 4-1/2 inches 50 Blows = 4-1/2 inches 50 Blows = 4 inches 517 513 511 508 499 494 489 SILTY CLAY, dark brown, hard, w/trace of sand (CH) SILTY CLAY, brownish-yellow, brown & gray, hard, w/sand & some iron stains (CH - CL) -w/trace of root @ 6' SILTY CLAY, brownish-yellow, light brown & gray, hard, w/iron stains & some sand (CH) GRAVELLY SAND, light brown, very dense, w/gravel, fine to coarse (SW) SAND, light brown, very dense, fine (SW) SAND, light brown & brownish-yellow, very dense, w/some gravel, fine to coarse (SP) Total Depth = 29.5 feet Seepage encountered @ 29' during drilling. Dry & blocked @ 28-1/2' @ end of day. Dry & blocked @ 26' on 11/29/2021. BORING LOG B-01 PLATE 2 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/24/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 50 Blows = 5-1/2 inches 520 518.5 515.5 511.5 507 504 497.5 SILTY CLAY, brown & yellowish-red, very stiff, w/trace of sand (CL) SILTY CLAY, dark brown, hard, w/some sand, trace of iron stains & ironstones (CH) SILTY CLAY, brown & brownish-yellow, hard, w/trace of calcareous deposits, calcareous concretions & sand (CL) SANDY CLAY, light brown, hard, w/trace of gravel & iron stains (CL - CH) SILTY CLAY, light brown, hard, w/trace of iron stains (CL) SAND, light brown, very dense, w/trace of silty clay, fine (SP) SAND, light brown, dense to very dense, fine to medium (SP) Total Depth = 30.5 feet Dry after 5 minutes. Dry & blocked @ 30' @ end of day. Dry & blocked @ 29-1/2' on 11/29/2021. BORING LOG B-02 PLATE 3 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/24/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 50 Blows = 2 inches 50 Blows = 4 inches 72 520 515.5 514 506 501.5 497.5 496 SILTY CLAY, dark brown, hard, w/some sand & trace of ironstones (CH) -w/trace of calcareous concretions below 4.5' SILTY CLAY, brownish-yellow & reddish-yellow, hard, w/sand, calcareous concretions & calcareous deposits (CL - CH) SANDY CLAY, light brown & brownish-yellow, hard, w/calcareous deposits (CL) SAND, light brown, very dense, fine (SP) GRAVELLY SAND, fine to coarse (SW) SAND, light brown, very dense, fine (weathered sandstone) (SP) Total Depth = 29.5 feet Dry after 5 minutes. Dry & blocked @ 29-1/2' @ end of day. Dry & blocked @ 29' on 11/29/2021. BORING LOG B-03 PLATE 4 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/24/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA >> GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 50 Blows = 1/2 inch 520 511.5 506 502 497 492.5 SILTY CLAY, dark brown, hard, w/some sand & trace of ironstones (CH) SILTY CLAY, brownish-yellow, yellowish-brown & reddish-yellow, very stiff to hard, w/sand & trace of iron stains (CH - CL) SILTY CLAY, reddish-yellow & brownish-yellow, hard, w/some sand (CH) CLAYEY SAND, light brown, brownish-yellow & reddish-yellow, w/trace or iron stains, fine (SC) CLAYEY SAND, light brown & reddish-yellow, w/some gravel & iron stains, fine to coarse (SC) GRAVEL, brown, very dense, w/sand (GP) Total Depth = 29.5 feet Dry after 5 minutes. Dry & blocked @ 28-1/2' @ end of day. Dry & blocked @ 28' on 11/29/2021. BORING LOG B-04 PLATE 5 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/24/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 50 Blows = 4 inches 50 Blows = 4 inches 521 516.5 515 514.5 509 504.5 497.5 495 SILTY CLAY, dark brown, hard (CH - CL) -w/trace of sand @ 4.5' -w/brown @ 6' SILTY CLAY, light brown & reddish-yellow, hard, w/trace of calcareous concretions, calcareous deposits & sand (CL) SANDY CLAY, light brown & brownish-yellow, hard, w/trace of calcareous concretions (CL - CH) SAND, reddish-yellow & light brown, dense, w/trace of silty clay seams, fine (SP) GRAVEL, brown, very dense, w/sand (GP) SAND, light brown, w/trace of gravel, fine (severely weathered sandstone) (SP) Total Depth = 31 feet Dry after 5 minutes. Dry & blocked @ 28-1/2' @ end of day. Dry & blocked @ 29' on 11/5/2021. BORING LOG B-05 PLATE 6 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/23/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas Seepage during drilling 519 516 510.5 506 502 496 490 SANDY CLAY, brown & yellowish-red, hard, w/trace of ironstones (CL) SILTY CLAY, dark brown, hard, w/some sand & trace of ironstones (CH) SILTY CLAY, brownish-yellow & reddish-yellow, hard, w/some sand (CL - CH) SANDY CLAY, light brown & reddish-yellow, hard (CL - CH) SAND, light brown, reddish-yellow & gray, medium dense, w/some silty clay seams, fine (SC - SP) GRAVELLY SAND, brown, dense, fine to coarse (SW) SANDY CLAY, light brown, very stiff, w/iron stains (CL) Total Depth = 30.5 feet Seepage encountered @ 30' during drilling. Dry after 7 minutes. Dry & blocked @ 29-1/2' @ end of day. Dry & blocked @ 29' on 11/29/2021. BORING LOG B-06 PLATE 7 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/24/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 50 Blows = 1/2 inch 520 515.5 514 513 504 496 SILTY CLAY, dark brown, hard (CH) -w/trace of calcareous concretions below 4.5' -w/brown & reddish-yellow below 6' SILTY CLAY, light brown & reddish-yellow, hard, w/trace of sand (CH) CLAYEY SAND, light brown & reddish-yellow, fine (SC) SAND, light brown & reddish-yellow, dense to very dense, w/trace of gravel, fine to coarse (SP) Total Depth = 31 feet Dry after 3 minutes. Dry @ end of day. Dry & blocked @ 29-1/2' on 11/24/2021. BORING LOG B-07 PLATE 8 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/23/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 518 513.5 512.5 510.5 504 496 488.2 488 SILTY CLAY, dark brown, very stiff to hard, w/trace of sand (CL) -w/brown & trace of calcareous concretions below 4.5' SILTY CLAY, brownish-yellow & reddish-yellow, hard, w/some calcareous deposits, calcareous concretions & trace of sand (CL) SILTY CLAY, light brown & reddish-yellow, very stiff to hard, w/trace of calcareous concretions & sand (CL) CLAYEY SAND, light brown & reddish-yellow, dense, fine to medium (SC) GRAVELLY SAND, brown & light brown, dense, fine to coarse (SW) -w/cobble @ 30' SAND, light brown & reddish-yellow, very dense, w/trace of gravel, fine to coarse (SW) Total Depth = 31.5 feet Dry after 3 minutes. Dry & blocked @ 30' @ end of day. Dry & blocked @ 29-1/2' on 11/24/2021. BORING LOG B-08 PLATE 9 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/23/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 512 510.5 SILTY CLAY, brown, hard, w/trace of sand, iron stains & ironstones (CH) SANDY CLAY, yellowish-brown & reddish-yellow, hard, w/trace of iron stains & calcareous concretions (CH - CL) Total Depth = 6 feet Dry after 5 minutes. Dry & blocked @ 6' @ end of day. BORING LOG B-09 PLATE 10 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/24/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 519 517.5 SANDY CLAY, dark brown, hard, w/iron stains (CL - CH) SILTY CLAY, dark brown, hard, w/trace of sand & iron stains (CH) Total Depth = 6 feet Dry after 5 minutes. Dry @ end of day. BORING LOG B-10 PLATE 11 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/24/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 520 517 515.5 SILTY CLAY, dark brown, stiff to hard, w/trace of sand (CH) -w/trace of calcareous concretions below 3' SILTY CLAY, brown & yellowish-brown, hard, w/trace of calcareous concretions, calcareous deposits & sand (CH) Total Depth = 6 feet Dry after 5 minutes. Dry @ end of day. BORING LOG B-11 PLATE 12 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/24/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 520 515.5 514.2 SILTY CLAY, dark brown, very stiff to hard (CH) -w/trace of calcareous concretions below 4.5' -w/brownish-yellow & reddish-yellow @ 6' Total Depth = 6 feet Dry after 5 minutes. Dry @ end of day. BORING LOG B-12 PLATE 13 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/23/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 521SILTY CLAY, dark brown, stiff to hard, w/trace of sand (CH) Total Depth = 6 feet Dry after 5 minutes. Dry @ end of day. BORING LOG B-13 PLATE 14 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/23/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 518 513.5 SILTY CLAY, dark brown, hard (CL) -w/trace of calcareous concretions & sand below 4.5' Total Depth = 6 feet Dry after 5 minutes. Dry @ end of day. BORING LOG B-14 PLATE 15 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/23/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 518 516.5 515 SILTY CLAY, dark brown, very stiff, w/some sand (CH) SILTY CLAY, brownish-yellow & gray, hard, w/trace of iron stains & sand (CH) -w/red @ 3' Total Depth = 6 feet Dry after 5 minutes. Dry @ end of day. BORING LOG B-15 PLATE 16 Location: See Plate 1 GraphicLogrec %(rqd %)SampleProject Number : 24459 Date Completed : 11/23/2021 REED ENGINEERING GROUP Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 612344.5+4.5++ Depth (ft) 5 10 15 20 25 30 35 Standard Penetration Tests Blows per Foot - 10 20 30 40 50 60 Elev. (ft)DESCRIPTION OF STRATA GEOTECHNICAL CONSULTANTS - locNEC West Sandy Lake Road and S.H. 121 POffice/Warehouse loc2Coppell, Texas 517 513 511 508 499 494 489 SILTY CLAY, dark brown, hard, w/trace of sand (CH) SILTY CLAY, brownish-yellow, brown & gray, hard, w/sand & some iron stains (CH - CL) -w/trace of root @ 6' SILTY CLAY, brownish-yellow, light brown & gray, hard, w/iron stains & some sand (CH) GRAVELLY SAND, light brown, very dense, w/gravel, fine to coarse (SW) SAND, light brown, very dense, fine (SW) SAND, light brown & brownish-yellow, very dense, w/some gravel, fine to coarse (SP) Total Depth = 29.5 ft Seepage encountered @ 29' during drilling. Dry & blocked @ 28-1/2' @ end of day. Dry & blocked @ 26' on 11/29/2021. 50 Blows = 4-1/2 inches 50 Blows = 4-1/2 inches 50 Blows = 4 inchesSeepage during drilling Project Number : 24459 Date Completed : 11/24/2021 REED ENGINEERING 1 3 4 4.5+ (weathered) LIMESTONE (unweathered) (weathered) SANDSTONE (unweathered) (weathered) SHALE (unweathered) CLAYEY GRAVEL (GRAVELLY CLAY) SILTY SAND (SM) CLAYEY SAND (SC) Location: See Plate 1 SAND (SP-SW) Elev. (ft) Pocket Penetrometer Readings Tons Per Sq. Ft. - 1 2 3 4 5 6 BORING LOG B-01 PLATE 2 UNDISTURBED (Shelby Tube & NX-Core) STANDARD PENETRATION TEST = Water level at time of drilling. DISTURBED THD CONE PENETROMETER TEST 4.5++ GROUP 2rec %(rqd %)SampleDepth (ft) 5 10 15 20 25 .Office/Warehouse GraphicLogPLATE 17 .NEC West Sandy Lake Road and S.H. 121 GRAVEL (GP-GW) SPT N VALUE 10 20 30 40 50 60 Fill Type of Fill Clay (CL) (LL<50) Clay (CH) (LL>50) SILT (ML) (LL<50) SILT (MH) (LL>50) = Subsequent water level and date. KEYS TO SYMBOLS USED ON BORING LOGS REED ENGINEERING GROUP DESCRIPTION OF STRATA . .Coppell, Texas GEOTECHNICAL CONSULTANTS - . GEOTECHNICAL CONSULTANTS - SPT N-Values (blows / foot) Relative Density Pocket Penetrometer (T.S.F.) Consistency 0 - 4 .....................Very Loose 4 - 10 .....................Loose 10 - 30 .....................Medium Dense 30 - 50 .....................Dense 50 + .....................Very Dense <0.25 .................... Very Soft 0.25-0.50 ............... Loose 0.50-1.00 ............... Medium Stiff 1.00-2.00 ............... Stiff 2.00-4.00 ............... Very Stiff 4.00 + .................... Hard SOIL PROPERTIES COHESIONLESS SOILS HARDNESS DIAGNOSTIC FEATURES ROCK PROPERTIES DEGREE OF WEATHERING DIAGNOSTIC FEATURES COHESIVE SOILS Very Soft ............... Soft ....................... Moderately Hard ... Hard ...................... Very Hard .............. Can be dented with moderate finger pressure. Can be scratched easily with fingernail. Can be scratched easily with knife but not with fingernail. Can be scratched with knife with some difficulty; can be broken by light to moderate hammer blow. Cannot be scratched with knife; can be broken by repeated heavy hammer blows. Slightly Weathered ......... Weathered ...................... Severely Weathered ....... Completely Weathered ... Slight discoloration inwards from open fractures. Discoloration throughout; weaker minerals decomposed; strength somewhat less than fresh rock; structure preserved. Most minerals somewhat decomposes; much softer than fresh rock; texture becoming indistict but fabric and structure preserved. Minerals decomposes to soil; rock fabric and structure destroyed (residual soil). KEYS TO DESCRIPTIVE TERMS ON BORING LOGS REED ENGINEERING GROUP PLATE 18 GEOTECHNICAL CONSULTANTS - SUMMARY OF LABORATORY TEST RESULTS PLATE 19 GEOTECHNICAL INVESTIGATION OFFICE/WAREHOUSE NEC WEST SANDY LAKE ROAD AND S.H. 121 COPPELL, TEXAS Summary of Classification and Index Property Tests Total Percent Percent Moisture Liquid Plastic Plasticity Soil Passing Passing Boring Depth Content Limit Limit Index Suction No. 200 No. 4 No. (feet) (%) (%) (%) (PI) (psf) Sieve Sieve B-1 0.0 - 1.5 19.0 -- -- -- 7,440 -- -- 1.5 - 3.0 14.6 54 17 37 29,220 -- -- 3.0 - 4.5 13.6 -- -- -- 33,820 -- -- 4.5 - 6.0 15.3 -- -- -- 32,360 -- -- 9.0 - 10.0 11.1 51 17 34 26,670 -- -- 14.0 - 15.0 15.6 -- -- -- 23,010 81 -- 19.0 - 20.0 3.0 -- -- -- -- -- -- B-2 0.0 - 1.5 18.2 38 16 22 1,270 -- -- 1.5 - 3.0 11.9 -- -- -- 40,160 -- -- 3.0 - 4.5 12.6 -- -- -- 30,790 -- -- 4.5 - 6.0 15.8 45 17 28 15,090 -- -- 9.0 - 10.0 13.1 -- -- -- 1,320 59 -- 14.0 - 15.0 14.4 -- -- -- 1,300 87 -- 19.0 - 20.0 6.2 -- -- -- -- -- -- B-3 0.0 - 1.5 14.3 -- -- -- 24,210 -- -- 1.5 - 3.0 15.6 -- -- -- 47,510 -- -- 3.0 - 4.5 13.5 48 18 30 45,310 79 -- 4.5 - 6.0 14.5 -- -- -- 45,180 -- -- 9.0 - 10.0 13.9 -- -- -- 29,000 -- -- 14.0 - 15.0 8.3 32 12 20 33,170 -- -- 19.0 - 20.0 0.3 -- -- -- -- 3 -- SUMMARY OF LABORATORY TEST RESULTS PLATE 20 GEOTECHNICAL INVESTIGATION OFFICE/WAREHOUSE NEC WEST SANDY LAKE ROAD AND S.H. 121 COPPELL, TEXAS (Continued) Summary of Classification and Index Property Tests Total Percent Percent Moisture Liquid Plastic Plasticity Soil Passing Passing Boring Depth Content Limit Limit Index Suction No. 200 No. 4 No. (feet) (%) (%) (%) (PI) (psf) Sieve Sieve B-4 0.0 - 1.5 15.6 -- -- -- 2,340 -- -- 1.5 - 3.0 14.9 50 18 32 27,370 -- -- 3.0 - 4.5 13.6 -- -- -- 23,860 -- -- 4.5 - 6.0 14.2 -- -- -- 13,750 -- -- 9.0 - 10.0 20.1 -- -- -- 1,340 -- -- 14.0 - 15.0 23.6 60 19 41 7,280 -- -- 19.0 - 20.0 9.3 -- -- -- 6,230 43 -- 24.0 - 25.0 7.6 -- -- -- 1,550 11 72 B-5 0.0 - 1.5 17.7 -- -- -- 25,380 -- -- 1.5 - 3.0 14.7 -- -- -- 57,300 -- -- 3.0 - 4.5 14.6 -- -- -- 63,540 -- -- 4.5 - 6.0 14.9 48 15 33 47,010 81 -- 9.0 - 10.0 17.3 -- -- -- 37,320 -- -- 14.0 - 15.0 10.9 -- -- -- 23,770 54 -- 19.0 - 20.0 4.2 -- -- -- -- -- -- B-6 0.0 - 1.5 14.3 -- -- -- 1,510 -- -- 1.5 - 3.0 13.7 40 16 24 71,540 72 -- 3.0 - 4.5 12.7 -- -- -- 62,740 -- -- 4.5 - 6.0 12.8 -- -- -- 52,870 -- -- 9.0 - 10.0 16.5 44 13 31 19,850 -- -- 14.0 - 15.0 14.2 37 11 26 9,010 56 -- 19.0 - 20.0 5.5 -- -- -- 6,390 -- -- SUMMARY OF LABORATORY TEST RESULTS PLATE 21 GEOTECHNICAL INVESTIGATION OFFICE/WAREHOUSE NEC WEST SANDY LAKE ROAD AND S.H. 121 COPPELL, TEXAS (Continued) Summary of Classification and Index Property Tests Total Percent Percent Moisture Liquid Plastic Plasticity Soil Passing Passing Boring Depth Content Limit Limit Index Suction No. 200 No. 4 No. (feet) (%) (%) (%) (PI) (psf) Sieve Sieve B-7 0.0 - 1.5 21.0 -- -- -- 11,280 -- -- 1.5 - 3.0 17.1 -- -- -- 40,000 -- -- 3.0 - 4.5 17.2 60 16 44 34,500 84 -- 4.5 - 6.0 19.6 -- -- -- 29,690 -- -- 9.0 - 10.0 17.3 56 18 38 18,410 92 -- 14.0 - 15.0 16.1 -- -- -- 14,960 88 -- 19.0 - 20.0 8.5 -- -- -- 24,060 38 -- 24.0 - 25.0 2.5 -- -- -- -- -- -- B-8 0.0 - 1.5 21.6 47 18 29 1,590 -- -- 1.5 - 3.0 16.4 -- -- -- 21,720 -- -- 3.0 - 4.5 17.2 -- -- -- 16,420 -- -- 4.5 - 6.0 14.0 45 16 29 12,450 -- -- 9.0 - 10.0 20.5 -- -- -- 2,850 88 -- 14.0 - 15.0 8.3 -- -- -- 1,300 22 -- 19.0 - 20.0 5.9 -- -- -- -- 15 -- B-9 0.0 - 1.5 17.1 52 16 36 -- -- -- 1.5 - 3.0 12.4 -- -- -- -- 77 -- 3.0 - 4.5 13.6 -- -- -- -- -- -- 4.5 - 6.0 14.7 -- -- -- -- -- -- B-12 0.0 - 1.5 21.5 -- -- -- -- -- -- 1.5 - 3.0 12.5 53 16 37 -- 82 -- 3.0 - 4.5 14.2 -- -- -- -- -- -- 4.5 - 6.0 13.9 -- -- -- -- -- -- SUMMARY OF LABORATORY TEST RESULTS PLATE 22 GEOTECHNICAL INVESTIGATION OFFICE/WAREHOUSE NEC WEST SANDY LAKE ROAD AND S.H. 121 COPPELL, TEXAS (Continued) Summary of Classification and Index Property Tests Total Percent Percent Moisture Liquid Plastic Plasticity Soil Passing Passing Boring Depth Content Limit Limit Index Suction No. 200 No. 4 No. (feet) (%) (%) (%) (PI) (psf) Sieve Sieve B-14 0.0 - 1.5 17.8 45 16 29 -- 77 -- 1.5 - 3.0 19.3 -- -- -- -- -- -- 3.0 - 4.5 13.8 -- -- -- -- -- -- 4.5 - 6.0 15.2 -- -- -- -- -- -- SUMMARY OF LABORATORY TEST RESULTS PLATE 23 Summary of Unconfined Compression Tests Dry Unconfined Moisture Unit Compressive Sample Boring Depth Content Weight Strength Legend No. (feet) (%) (pcf) (ksf) A B-1 14.0 - 15.0 15.4 111.7 15.6 B B-2 9.0 - 10.0 12.5 115.3 5.0 C B-4 9.0 - 10.0 16.6 114.5 3.9 D B-4 14.0 - 15.0 23.4 103.8 9.4 E B-5 9.0 - 10.0 16.0 116.0 14.3 F B-6 4.5 - 6.0 12.2 118.6 29.5 SUMMARY OF LABORATORY TEST RESULTS PLATE 24 Summary of Unconfined Compression Tests Dry Unconfined Moisture Unit Compressive Sample Boring Depth Content Weight Strength Legend No. (feet) (%) (pcf) (ksf) A B-7 14.0 - 15.0 15.3 113.0 15.7 B B-8 9.0 - 10.0 18.9 111.8 5.1 SUMMARY OF LABORATORY TEST RESULTS PLATE 25 Absorption Pressure Swell Test Initial Final Project No. 24459 Moisture Content (%) 10.9 18.6 Boring No. B-1 Penetrometer (tsf) 4.5++ 3.5 Depth (ft) 9-10 Dry Unit Weight (pcf) 111.1 108.6 Liquid Limit 51 Specific Gravity 2.71 2.71 Plasticity Index 34 Void Ratio 0.522 0.558 Cs 0.035 Saturation (%) 57 91 alpha 0.17 Spec. Volume 0.56 0.57 Percent Swell 2.3 Swell Pressure (psf) 2,590 250 SUMMARY OF LABORATORY TEST RESULTS PLATE 26 Absorption Pressure Swell Test Initial Final Project No. 24459 Moisture Content (%) 8.9 17.0 Boring No. B-3 Penetrometer (tsf) 4.5++ 3 Depth (ft) 14-15 Dry Unit Weight (pcf) 113.9 111.3 Liquid Limit 32 Specific Gravity 2.71 2.71 Plasticity Index 20 Void Ratio 0.485 0.519 Cs 0.039 Saturation (%) 50 88 alpha 0.16 Spec. Volume 0.55 0.56 Percent Swell 2.3 Swell Pressure (psf) 1,940 250 SUMMARY OF LABORATORY TEST RESULTS PLATE 27 Absorption Pressure Swell Test Initial Final Project No. 24459 Moisture Content (%) 17.3 22.4 Boring No. B-6 Penetrometer (tsf) 4.5++ 3 Depth (ft) 9-10 Dry Unit Weight (pcf) 111.9 105.8 Liquid Limit 44 Specific Gravity 2.73 2.73 Plasticity Index 31 Void Ratio 0.523 0.610 Cs 0.058 Saturation (%) 90 100 alpha 0.63 Spec. Volume 0.56 0.59 Percent Swell 5.7 Swell Pressure (psf) 7,780 250 SUMMARY OF LABORATORY TEST RESULTS PLATE 28 Absorption Pressure Swell Test Initial Final Project No. 24459 Moisture Content (%) 17.8 22.6 Boring No. B-7 Penetrometer (tsf) 4.5++ 3 Depth (ft) 9-10 Dry Unit Weight (pcf) 110.5 106.0 Liquid Limit 56 Specific Gravity 2.75 2.75 Plasticity Index 38 Void Ratio 0.553 0.618 Cs 0.050 Saturation (%) 88 100 alpha 0.49 Spec. Volume 0.56 0.59 Percent Swell 4.2 Swell Pressure (psf) 5,180 250 SPECIFICATIONS Project No. 24459 - 1 - Water Injection Specifications December 22, 2021 w/“Select” Fill Cap GUIDELINE SPECIFICATIONS SOIL MODIFICATION WATER INJECTION W/“SELECT” FILL CAP FOR OFFICE/WAREHOUSE NEC WEST SANDY LAKE ROAD AND S.H. 121 COPPELL, TEXAS Site Preparation Prior to the start of injection operations, the building pad should be brought to finished subgrade, minus select fill, and staked out to accurately mark the areas to be injected. Allowance should be made for two to four inches of swelling that may occur as a result of the injection process. Materials 1. The water shall be potable, with added surfactant, agitated as necessary to ensure uniformity of mixture. 2. A nonionic surfactant (wetting agent) shall be used according to manufacturer's recommendations; but in no case shall proportions be less than one part (undiluted) per 3,500 gallons of water. Equipment 1. The injection vehicle shall be capable of forcing injection pipes into soil with minimum lateral movement to prevent excessive blowback and loss of slurry around the injection pipes. The vehicle may be a rubber tire or trac machine suitable for the purpose intended. 2. Slurry pumps shall be capable of pumping at least 3,000 GPH at 100 - 200 pounds per square inch (psi). Application 1. The injection work shall be accomplished after the building pad has been brought to finished subgrade, minus select fill, and prior to installation of any plumbing, utilities, ditches or foundations. 2. Adjust injection pressures within the range of 100 - 200 psi at the pump. Project No. 24459 - 2 - Water Injection Specifications December 22, 2021 w/“Select” Fill Cap 3. Space injections not to exceed five feet on-center each way and inject a minimum of five feet outside building area. Inject 10 feet beyond building at entrances. 4. Inject to Elev. 510 or impenetrable material, whichever occurs first. Impenetrable material is the maximum depth to which two injection rods can be mechanically pushed into the soil using an injection machine having a minimum gross weight of 5 tons. Injections to be made in 12-inch to 18-inch intervals down to the total depth with a minimum of 7 stops or intervals. The lower portion of the injection pipes shall contain a hole pattern that will uniformly disperse the slurry in a 360 radial pattern. Inject at each interval to "refusal." Refusal is reached when water is flowing freely at the surface, either out of previous injection holes or from areas where the surface soils have fractured. Fluid coming up around, or in the vicinity, of one or more of the injection probes shall not be considered as soil refusal. If this occurs around any probe, this probe shall be cut off so that water can be properly injected through the remaining probes until refusal occurs for all probes. In any event, no probe shall be cut off within the first 30 seconds of injection at each depth interval. 5. Multiple injections with water and surfactant will be required. The second injection shall be orthogonally offset from the initial injection by 2-1/2 feet in each direction. Subsequent injections shall be offset such that existing probe holes are not utilized. 6. A minimum of 48 hours shall be allowed between each injection pass. 7. Injections will be continued until a pocket penetrometer reading of 3.0 tsf or less is obtained on undisturbed soil samples throughout the injected depth. The engineer of record can waive this requirement if, in his opinion, additional injections will not result in additional swelling. 8. At the completion of injection operations, the exposed surface shall be scarified and recompacted to at least 95 percent of maximum density, ASTM D698, at or above optimum moisture. A minimum of 12 inches of select fill shall be placed over the injected subgrade as soon as is practical after completion of injection operations. Select fill should be placed in maximum loose lifts of 8 inches and compacted to at least 95 percent of maximum density, ASTM D698, at a moisture content between - 2 to +3 percentage points of optimum. Project No. 24459 - 3 - Water Injection Specifications December 22, 2021 w/“Select” Fill Cap Observation and Testing 1. A full-time representative of Reed Engineering Group, Ltd. will observe injection operations. 2. Undisturbed soil samples will be obtained continuously throughout the injected depth, at a rate of one test hole per 10,000 square feet of injected area for confirmation. Sampling will be performed a minimum of 48 hours after the completion of the final injection pass. Project No. 24459 - 1 - Water Injection Specifications December 22, 2021 w/“Flexible Base” Cap GUIDELINE SPECIFICATIONS SOIL MODIFICATION WATER INJECTION W/“FLEXIBLE BASE” CAP FOR OFFICE/WAREHOUSE NEC WEST SANDY LAKE ROAD AND S.H. 121 COPPELL, TEXAS Site Preparation Prior to the start of injection operations, the building pad should be brought to finished subgrade, minus flexible base, and staked out to accurately mark the areas to be injected. Allowance should be made for two to four inches of swelling that may occur as a result of the injection process. Materials 1. The water shall be potable, with added surfactant, agitated as necessary to ensure uniformity of mixture. 2. A nonionic surfactant (wetting agent) shall be used according to manufacturer's recommendations; but in no case shall proportions be less than one part (undiluted) per 3,500 gallons of water. Equipment 1. The injection vehicle shall be capable of forcing injection pipes into soil with minimum lateral movement to prevent excessive blowback and loss of slurry around the injection pipes. The vehicle may be a rubber tire or trac machine suitable for the purpose intended. 2. Slurry pumps shall be capable of pumping at least 3,000 GPH at 100 - 200 pounds per square inch (psi). Application 1. The injection work shall be accomplished after the building pad has been brought to finished subgrade, minus flexible base, and prior to installation of any plumbing, utilities, ditches or foundations. 2. Adjust injection pressures within the range of 100 - 200 psi at the pump. Project No. 24459 - 2 - Water Injection Specifications December 22, 2021 w/“Flexible Base” Cap 3. Space injections not to exceed five feet on-center each way and inject a minimum of five feet outside building area. Inject 10 feet beyond building at entrances. 4. Inject to Elev. 510 or impenetrable material, whichever occurs first. Impenetrable material is the maximum depth to which two injection rods can be mechanically pushed into the soil using an injection machine having a minimum gross weight of 5 tons. Injections to be made in 12-inch to 18-inch intervals down to the total depth with a minimum of 7 stops or intervals. The lower portion of the injection pipes shall contain a hole pattern that will uniformly disperse the slurry in a 360 radial pattern. Inject at each interval to "refusal". Refusal is reached when water is flowing freely at the surface, either out of previous injection holes or from areas where the surface soils have fractured. Fluid coming up around, or in the vicinity, of one or more of the injection probes shall not be considered as soil refusal. If this occurs around any probe, this probe shall be cut off so that water can be properly injected through the remaining probes until refusal occurs for all probes. In any event, no probe shall be cut off within the first 30 seconds of injection at each depth interval. 5. Multiple injections with water and surfactant will be required. The second injection shall be orthogonally offset from the initial injection by 2-1/2 feet in each direction. Subsequent injections shall be offset such that existing probe holes are not utilized. 6. A minimum of 48 hours shall be allowed between each injection pass. 7. Injections will be continued until a pocket penetrometer reading of 3.0 tsf or less is obtained on undisturbed soil samples throughout the injected depth. The engineer of record can waive this requirement if, in his opinion, additional injections will not result in additional swelling. 8. At the completion of injection operations, the exposed surface shall be scarified and recompacted to at least 95 percent of maximum density, ASTM D698, at or above optimum moisture. A minimum of 6 inches of flexible base shall be placed over the injected subgrade as soon as is practical after completion of injection operations. Flexible base is defined as material meeting TxDOT Specifications, Item 247, Type D, Grade 1 or 2 or better. This may include crushed concrete. Flexible base should be compacted to at least 95 percent of the Standard Proctor density, at a moisture content between -2 to +3 percentage points of optimum moisture. Project No. 24459 - 3 - Water Injection Specifications December 22, 2021 w/“Flexible Base” Cap Observation and Testing 1. A full-time representative of Reed Engineering Group, Ltd. will observe injection operations. 2. Undisturbed soil samples will be obtained continuously throughout the injected depth, at a rate of one test hole per 10,000 square feet of injected area for confirmation. Sampling will be performed a minimum of 48 hours after the completion of the final injection pass. Project No. 24459 - 1 - Water Injection Specifications December 22, 2021 w/Lime-Modified Cap GUIDELINE SPECIFICATIONS SOIL MODIFICATION WATER INJECTION W/LIME-MODIFIED CAP FOR OFFICE/WAREHOUSE NEC WEST SANDY LAKE ROAD AND S.H. 121 COPPELL, TEXAS Site Preparation Prior to the start of injection operations, the building pad should be brought to finished subgrade and staked out to accurately mark the areas to be injected. Allowance should be made for two to four inches of swelling that may occur as a result of the injection process. Materials 1. The water shall be potable, with added surfactant, agitated as necessary to ensure uniformity of mixture. 2. A nonionic surfactant (wetting agent) shall be used according to manufacturer's recommendations; but in no case shall proportions be less than one part (undiluted) per 3,500 gallons of water. Equipment 1. The injection vehicle shall be capable of forcing injection pipes into soil with minimum lateral movement to prevent excessive blowback and loss of slurry around the injection pipes. The vehicle may be a rubber tire or trac machine suitable for the purpose intended. 2. Slurry pumps shall be capable of pumping at least 3,000 GPH at 100 - 200 pounds per square inch (psi). Application 1. The injection work shall be accomplished after the building pad has been brought to finished subgrade and prior to installation of any plumbing, utilities, ditches or foundations. 2. Adjust injection pressures within the range of 100 - 200 psi at the pump. 3. Space injections not to exceed five feet on-center each way and inject a minimum of five feet outside the building footprint. Inject 10 feet beyond building at entrances. Project No. 24459 - 2 - Water Injection Specifications December 22, 2021 w/Lime-Modified Cap 4. Inject to Elev. 510 or impenetrable material, whichever occurs first. Impenetrable material is the maximum depth to which two injection rods can be mechanically pushed into the soil using an injection machine having a minimum gross weight of 5 tons. Injections to be made in 12-inch to 18-inch intervals down to the total depth with a minimum of 7 stops or intervals. The lower portion of the injection pipes shall contain a hole pattern that will uniformly disperse the slurry in a 360 radial pattern. Inject at each interval to "refusal". Refusal is reached when water is flowing freely at the surface, either out of previous injection holes or from areas where the surface soils have fractured. Fluid coming up around or in the vicinity of one or more of the injection probes shall not be considered as soil refusal. If this occurs around any probe, this probe shall be cut off so that water can be properly injected through the remaining probes until refusal occurs for all probes. In any event, no probe shall be cut off within the first 30 seconds of injection after refusal at each depth interval. (The 30-second criterion is not the maximum time for each depth interval but a minimum time. Additional time may be required to achieve refusal, dependent upon the contractor's equipment.) 5. Multiple injections with water and surfactant will be required. The second injection shall be orthogonally offset from the initial injection by 2-1/2 feet in each direction. Subsequent injections shall be offset such that existing probe holes are not utilized. 6. A minimum of 48 hours shall be allowed between each injection pass. 7. Injections will be continued until a pocket penetrometer reading of 3.0 tsf or less is obtained on undisturbed soil samples throughout the injected depth. The engineer of record can waive this requirement if, in his opinion, additional injections will not result in additional swelling. 8. At the completion of injection operations, the exposed surface shall be scarified and blended with a minimum of 6 percent hydrated lime, or 27 pounds of lime per square yard, to a depth of 6 inches. The subgrade shall then be recompacted to at least 95 percent of maximum density, ASTM D698, at or above optimum moisture. Project No. 24459 - 3 - Water Injection Specifications December 22, 2021 w/Lime-Modified Cap Observation and Testing 1. A full-time representative of Reed Engineering Group, Ltd. will observe injection operations. 2. Undisturbed soil samples will be obtained continuously throughout the injected depth, at a rate of one test hole per 10,000 square feet of injected area for confirmation. Sampling will be performed a minimum of 48 hours after the completion of the final injection pass.