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SS9301-SY 920623 SUBSURFACE EXPLORATION FOR GRAPEVINE CREEK SEWER TRUNK MAIN PHASE II COPPELL, TEXAS Prepared For Ginn and Case, Inc. Dallas, Texas June 23, 1992 SWL Report No. 91-586-2 Materials, environmental and geotechnical engineering, nondestructive, metallurgical and analytical services 257~5 I_one Sr~r [Drive · {~. O. Box 224227, Oellas, Texas 75222 · 214/631-2700 June 23, 1992 Ginn and Case, Inc. 17103 Preston Road ..... Suite 100 Dallas, Texas 75248 -- Attention: Mr. Gabe Favre Re: Subsurface Investigation Proposed Grapevine Creek Sewer Trunk Main-Phase II Coppell, Texas .... Draft of SWL Report No. 91-586-2 Dear Mr. Favre: Attached is our geotechnical report for the above referenced project. This investigation was authorized by Mr. Sanford W. Case on October 17, 1992. It has been a pleasure to perform this work for you. If, during the course of this project we can be of further - assistance, please do not hesitate to call on us. Sincerely, SOUTHWESTERN LABORATORIES, INC. -- ~'mmar itu, v.~. Geotechnical Division Michael L. Lester, P.E. Senior Project Manager Geotechnical Division "' CBB: MLL: eb Attachment HOUSTON · DALLAS · AUSTIN · BEAUMONT · GALVESTON CObNTY · R O GRANDE VALLEY · A!_EXAN[DRIA SAN ANTONIO · FORT WORTH · MIDLAND · MONROE · SHREVEPORT · TEXARKANA · [DEN;SON · BATON ROUGE TABLE OF CONTENTS Page Project Information ................................ 1 Scope of Investigation ............................. 2 Field Operations ................................... 3 Laboratory Testing ................................. 5 Geology/Subsurface Conditions ...................... 6 Active Clays ................................... 8 Groundwater .................................... 8 Analysis and Recommendations Allowable Bearing Pressures .................... 9 Construction Considerations-Footings ........... 12 Trench and Manhole Excavations ................. 13 Construction Considerations-Trench Excavations..17 Trench Backfill ................................ 18 Bore Tunnel Excavations ........................ 20 Limitations and Reproductions ...................... 21 APPENDIX · - Table 1 - Observation Well Readings .............. A-1 Figure 1 - Design Illustration Utility Trench Open Cut Configurations ........ A-2 _ Figure 2 - Earth Pressures for Temporary Braced or Tied Back Shoring ........... A-3 Figure 3 - Boring Location Diagram ................ A-4 Figure 4 - Soil and Shale Stratigraphy ............ A-5 .... Logs of Boring .................................... A-6 Grain Size Distribution ........................... A-15 SOUTHWESTERN L ABOR~-TOR'E$ SUBSURFACE INVESTIGATION _ PROPOSED GRAPEVINE CREEK SEWER MAIN PHASE I COPPELL, TEXAS PROJECT INFORMATION The Phase II sewer alignment has recently been revised to reflect changes in the Phase I alignment to avoid placing sections of the sewer route in Grapevine Creek. The new alignment for Phase II will consist of approximately 4,200 linear feet of 24-inch diameter PVC sanitary sewer line. This alignment will begin on Bethel Road just west of Denton Tap Road at approximately Sta. 6+15. The line will follow Bethel Road westward to approximately Sta. 15+67 where it turns south and crosses Bethel Road on the east side of Grapevine Creek. The sewer alignment then generally follows the Grapevine Creek, remaining east of the creek to its termination at Coppell Road. The proposed sewer line will be approximately 18 feet deep as it passes under Denton Tap Road at Bethel Road. As the sewer line progresses west from Denton Tap Road, _ it will increase in depth to approximately 30 feet, due SOUTHWESTERN LABOR&TO~IES 91-586 -1- a rise in profile grade elevation of Bethel road. As surface grades then gradually drop moving west on Bethel Road, the sewer line will again be approximately 20 feet below grade. As the sewer turns to the south at Grapevine creek, its depth will generally vary between 6 to 25 feet, with sections of the line on the order of 10 foot deep or shallower encased in concrete. Plans indicate that the sewer alignment will be bored between Sta. 38+44 to Sta. 40+00 to pass beneath the St. Louis and Southwest Railroad Line and a high pressure gas line. The sewer line will gradually become more shallow to the south and will be approximately 11 feet below grade at its termination near Sta. 48+20. SCOPE OF INVESTIGATION The purposes of the study were to: 1) explore the subsurface conditions at the site, 2) evaluate the pertinent engineering properties of the subsurface materials, 3) discuss subsurface and groundwater conditions along the alignment and how they will affect the proposed construction, 4) provide allowable bearing pressures for manholes and other structures along the alignment, and 5) provide minimum side slopes for trench SOU TH~/~£$TERN LABOI~TOR'E$ 91-586 -2- excavations and pressure envelopes for braced shoring of trench excavations. FIELD OPERATIONS A total of 11 borings were initially proposed to investigate subsurface conditions along the original alignment. Due to recent changes in the alignment, fewer borings were required to maintain the desired boring spacing of approximately 500 feet for our subsurface explorations. A total of 9 borings have been completed along the Phase II section of the proposed sewer line. Borings were not made for the section of the line replaced by the new Bethel Road alignment. Test borings were made at the site during the period February 11 to May 12, 1992, at the approximate locations shown on the Boring Location Diagram in the Appendix. Truck-mounted and all terrain vehicle (ATV) mounted auger drilling rigs were used to advance these borings and to obtain samples for laboratory evaluation. Undisturbed specimens of cohesive soils were obtained at intermittent intervals with standard, thin-walled, seamless Shelby tube samplers. These specimens were extruded in the field, logged, sealed and packaged to 91-586 -3- protect them from disturbance and maintain their in-situ moisture content during transportation to our laboratory. Where cohesionless soils, stiff clay soils and shales were encountered, an indication of their density or hardness was obtained by means of the Standard penetration test. This test consists of determining the number of blows required for a 140 pound hammer falling 30 inches to drive a standard split-spoon sampler 12 inches into the soil. The consistency of the shales were also evaluated during drilling by the Texas Highway Department (THD) Cone Penetrometer Test. This test consists of determining the penetration of a 3-inch diameter cone driven with an approximate energy equivalent of a 170-pound hammer falling 24 inches. Observation wells were installed in Borings B2-SA and B2-9A after the borings were completed. These wells were installed to facilitate long-term water level measurements at these locations. 91-586 -4- Wells were constructed by installing 2-inch diameter PVC _ screen pipe from the bottom of the hole to within 18 inches of the ground surface. A blank PVC riser pipe was attached to the top of this screen to extend the well slightly above the ground surface. The screen pipe interval was backfilled with coarse sand to within a foot of the ground surface where a bentonite seal was provided to prevent surface water infiltration into the well. The results of the boring program are presented on the Logs of Boring in the Appendix. Observation well readings are provided on Table 1 in the Appendix. ..- LABORATORY TESTING Samples were examined at our laboratory by the project geotechnical engineer. Selected samples were subjected to laboratory tests under the supervision of this engineer. The boring logs were edited by this engineer to reflect visual examination of the samples and the results of laboratory testing. The in-situ unit weight and moisture content of the samples were determined and used in conjunction with the Atterberg Limits tests to evaluate the potential volumetric change of the different strata, and as an "- indication of the uniformity of the material. 91-586 -5- Unconfined compression tests were performed on selected undisturbed samples of the cohesive soils. These tests were performed to evaluate the strength of these materials. The results of our testing program are presented on the Logs of Boring in the Appendix. Based on the results of these tests, the natural soils were classified using the - Unified Soil Classification System (USCS) and these classifications are indicated on the logs. GEOLOGY/SUBSURFACE CONDITIONS The subsurface conditions encountered in the borings are presented on the Logs of Boring in the Appendix. Detailed descriptions of the various strata and their depths and thicknesses are given. A brief summary of the stratigraphy and geology indicated by the borings is given below. Subsurface conditions encountered along the alignment generally varied with location due to the close proximity of Grapevine Creek. The borings along the Phase II alignment generally indicated that most of the residual clays of the Eagle Ford Formation have been eroded along the alignment and sandy, alluvial soils have replaced 91-586 -6- these clays. Grading of the area has also resulted in the fill materials encountered in some borings locations. - Shallow fill soils (less than 1 foot thick) were encountered along Bethel Road, with deeper fills (6.5 to 12 feet thick encountered in Borings B2-7, B2-9 and B2-10. The fill soils generally consisted of sandy clays mixed with some clay and silty clay soils and varying amounts of gravel and rock fragments. In general, the alluvial overburden soils that predominate along the Phase II alignment consisted of sandy to silty clays near the ground surface, gradually grading to silty sands and clayey sands with depth. Sands were predominate in Borings B2-5 and B2-10. The sands in Boring B2-11 continued to termination of this boring at a depth of 18 feet. Sands were generally not encountered in Boring B2-8 except for clayey sand seams near the top of the shale. -- An interval of clay (CH or CL) was generally encountered below the sands and above the shale. Some of these clays contained gravel seams. Shales were encountered at depths of 12 to 20 feet, and were as deep as 28 feet in Boring B2-2. In borings where shale was encountered, the 91-586 -7- borehole was terminated in this shale 14 to 32 feet below the existing ground surface. Active Clays The Atterberg limits series tests indicate that the sandy clay soils predominate at this site are moderately active. Active clays are subject to moisture induced volume changes (expansion and contraction) with fluctuations in their moisture content. Groundwater Groundwater seepage was encountered while advancing most of the borings, with the exception of Borings B2-6 and B2-7. Water was typically encountered while advancing the borings at depths of 9 to 16 feet, and in Boring B2-2A at a depth of 23 feet. Water levels were measured at depths of 15 to 28 feet at completion of the borings, with the exception of Borings B2-5, B2-6 and B2-7 where no water was encountered. Groundwater conditions at specific boring locations are described on the Logs of Boring in the Appendix. Water levels measured in the observation wells are recorded on Table I in the Appendix. 91-586 -8- Water was generally encountered in the sandy soils overlying the deeper clays and shales. Seepage was also present in the deeper fill soils in Boring B2-9. Water levels will tend to fluctuate due to seasonal variations in rainfall and could fluctuate with in the water level in Grapevine Creek. Seepage will most likely be encountered in the sandy alluvial soils and deep fills, particularly during wet periods of the year. The possibility of encountering seepage increases at locations closer to the creek. ANALYSIS AND RECOMMENDATION - Allowable Bearing Pressures Subgrade soils and shale strata beneath structures such as manholes located along the alignment will vary with location and the depth of the proposed sewer line. suitable bearing pressures for these structures will depend on the type and condition of bearing materials present. The borings indicate shales will be present at or near the sewer invert elevation and manhole foundations from Denton Tap Road westward along most of the alignment. Old creek channels may have eroded these shales and resulted SOUTH~ESTER~ LABOR&TOR'ES 91-586 -9- in deeper shale overlain by sandy soils in some local areas. Toward the southern end of the Phase II alignment, south of Boring B2-8 (Sta. 36+00), the shales and overlying shaly clays become deeper relative to the sewer flowline elevation. Shaly clays or sands will most likely be encountered in the bottom of the sewer trench excavations. At the south end of the line (Boring B2-11), the shales and shaly clays were not encountered. It is anticipated that silty sands will be encountered near the bottom of the sewer excavations in this area. The shales anticipated at/or near the base of the majority of the manhole excavations along the alignment excavations are considered hard in consistency. A maximum allowable bearing pressure of 5,000 pounds per square foot can be used for footings or structure bottoms bearing at least 6 inches into the undisturbed shale along this section of the alignment. It may be necessary to perform some overexcavation of manhole footings to bear in unweathered firm shale where erosion has resulted in deeper shale. Care should be taken that excavations penetrate any soft weathered shale encountered in the transition from clay to shale to use the above design bearing pressure. A factor of safety of at least 3 is included in the allowable bearing value given for these materials. 91-586 -10- Toward the southern end of the alignment, manhole excavation will gradually be terminated in the shaly clays overlying the shale strata. Similar shaly clays -- may be present at the base of manholes along central and eastern portions of the alignment where shales were eroded to a greater depth than encountered in the borings. These shaly clays are typically stiff to very stiff in consistency. We recommend a maximum allowable - bearing pressure of 3,000 pounds per square foot be used in this clay layer. The allowable bearing value given for these clays has a factor of safety of at least 3 is included in the allowable bearing pressure of these clays. If greater load carrying capacity is desired, consideration can be given to overexcavting the manhole excavations to bear in the underlying shale strata. The depth to these shales will generally increase at locations to the south. At the southern end of the alignment, the manhole excavations will gradually rise relative to the shales and shaly clays resulting in excavations most likely terminating in the overlying sands. These sands are medium dense in consistency. We recommend a maximum allowable bearing pressure of 3,000 pounds per square foot. This bearing pressure also includes a factor of safety of at least 3 against a general-shear failure. 91-586 -11- Construction Considerations-Footings Excavation of the footings, placement of concrete and steel, and any required backfilling should proceed in as continuous a manner as practical. This will serve to minimize deterioration of the bearing surfaces. Footing excavations should be maintained at/or near their in-situ moisture levels prior to concrete placement. Any bearing surface subjected to ponding of water should be excavated to firm clay or rock immediately prior to concrete placement. If bearing soils are allowed to become dry, post-construction movement of footings can occur due to volume changes in these active clays. Footing excavations which will remain open for more than 48 hours should be protected by a 3 to 4 inch seal (mud) slab of footing strength concrete. Individual footings may be square, round, or rectangular and should maintain a minimum width of 3 feet. Concrete should be placed directly against the sides of footing excavations with no loose or pervious backfill placed below the level of the general excavation and around the structure. SOUTHWESTERN LABORATOR ES 91-586 -12- Trench and Manhole Excavations Excavations along the proposed alignment will encounter a variety of conditions. In general, the stratigraphy will be silty to sandy clays grading to silty sands, clayey sands and sand and gravel mixtures with depth. Some of these surficial clay soils will be fill materials and could contain various amounts of sand, gravel, debris, etc. Sand and clayey sand intervals of varying thickness will be encountered in most of the borings. Thicker sand intervals are anticipated in the vicinity of Borings B2-1A, B2-2A, B2-5, B2-7, B2-9, B2-10 and B2-11. In general, most trench excavations will not exceed 20 feet. In areas where excavations will be greater than 20 feet, shale will most likely be encountered before the excavations reach the 20 foot depth. In the vicinity of Boring B2-2A, excavations will be on the order of 30 feet and shale is present at 28 feet. It is our understanding that all excavation operations for the project will be short term and therefore excavations will not remain open - for more than 72 hours. The clay soils, clay fill materials and sand soils are subject to caving and must be sloped back or braced in the interest of safety. Excavations in the firm 91-586 -13- unweathered gray shale can be cut on near vertical slopes for short periods; however, due to the presence of possible joints, bentonite seams and old fault planes, they should be shielded and very carefully monitored by qualified personnel to identify areas which could require additional support or bracing. Along a significant portion of the alignment, it is anticipated that groundwater will be encountered. Based on the results of the boring program, seepage and/or groundwater levels were measured above the planned depth of the sewer installation. Very little or no seepage was - encountered in Borings B2-5, B2-6 and B2-7. These borings did contain significant sand strata and we do anticipate groundwater in this area, particularly during wet periods of the year. Water in this sand would be expected to increase th~ instability of these sands. Dewatering with well points or other dewatering techniques may be necessary prior to beginning trench excavations. Where the bottom of the trench consist of sands or clays, groundwater should be drawn down several feet below the trench bottom while the excavation is .... open. The groundwater will primarily be moving in the sandy overburden soils above the shale and/or at various depths 91-586 -14- in existing fill materials. The quantity of ground water will also be influenced by seasonal conditions. During periods of seasonal rain, greater quantities of groundwater should be expected. Seepage in the clays fill soils will most likely occur in less compacted zones and/or in the more sandy soils in these fills and can often be controlled by pumping the water from low points along the trench. Seepage in the sandy alluvial soils is expected to be more significant and dewatering techniques such as well points could be required, particularly if construction proceeds during a wet period of the year. Care must be taken when excavating near and below any existing utility trenches. The backfill materials for these lines may be loose and saturated. Careful observations will be required to determine if changes in the side slopes or temporary bracing are necessary. Where gravel backfill materials are encountered, sloughing and caving of these materials will require that they be sloped flatter than indicated or that continuous shoring is used. 91-586 -15- Design illustrations for temporary trench excavation slopes are presented on Figure 1 in the Appendix. As indicated on this illustration, different side slopes are recommended based on the material type present. An earth pressure envelope for temporary shoring of the trench excavation is presented on Figure 2. Surcharge loads (due to traffic, equipment, spoil material, etc.) __ must be considered when they are located closer than one-half the depth of the excavation. A minimum surcharge equivalent of two feet of soil is recommended. Therefore, the depth to the bottom of the excavation (H) or the depth to unweathered shale (H) should be increased _ by two feet or more. For calculation of surcharge loads, use of a soil unit weight of 125 pounds per cubic foot is recommended. Excavations made in close vicinity to any existing structures may require use of retention systems to prevent excavation limits from encroaching on these --- structures. It should be recognized that movement of the ground behind the retention system will occur. The extent of movement and any resulting damage is highly dependent on the workmanship and procedures used in constructing and removing the retention system. This 91-586 -16- office should be contacted to evaluate existing structures with foundations bearing within a 1 horizontal to 1 vertical slope from the base of the proposed excavation. Underpinning of the nearby portions of the existing structures may be necessary to reduce potential movements of these structures. Construction Considerations-Trench Excavations In the event a trench box is utilized, the manufacturer of the box should certify that the trench box will resist an active earth pressure of 85 pounds per square foot per foot of depth. SwL also emphasizes the importance of continuous observations by qualified geotechnical personnel during trenching or excavation operations at the site. These observations are required to verify that the conditions encountered are as anticipated, that side slopes are as recommended, or that shoring is as specified. The relatively rapid excavation and cover process associated with pipe installations will require that these personnel be capable of making on site decisions regarding changes in the side slopes or shoring or that work in a given area should be halted until additional investigations and analyses can be performed. 91-586 -17- Pressure diagrams and slope configurations represent recommended design approaches consistent with generally accepted practice. Proper monitoring during construction must be provided to verify the subsurface conditions and confirm that these recommendations are applicable. Any changes in subsurface conditions must be evaluated to determine if adjustments are necessary in shoring or slope configurations. The contractor is solely responsible for designing and constructing stable, temporary excavations and should shore, slope, or bench the sides of the excavations as required to maintain stability of both the excavation sides and bottom. All excavations should comply with applicable local, state and federal safety regulations including the current OSHA Excavation and Trench Safety Standards. The contractor is responsible for construc- tion site safety through the means, methods and sequencing of construction activities. Trench Backfill We recommend that utility trenches be backfilled in lifts with density controlled compaction to prevent unusual settlement. We do not recommend the use of jetting, even if granular (sandy) backfill materials are used. All 91-586 -18- trenches and excavations should comply with OSHA and state law requirements for trench safety. Where trenches are located in existing and/or proposed paving and structure areas and trench backfill is made with on-site swelling soils (PI >20), we recommend the fill be placed in loose lifts less than 9 inches thick, compacted between 93 percent and 98 percent of Standard Proctor density (ASTM D 698) at optimum moisture to five percent above the soil's optimum moisture content. Where backfill will exceed four feet in depth, minimum compaction of deeper backfill material should be increased to between 95 and 100 percent. Properly compacted fill sections up to 20 feet deep could settle on the order of 2 to 3 inches after construction. Granular, generally non-active to slightly active, soils (PI < 20) should be compacted to a minimum of 95 percent of Standard Proctor density (ASTM D 698). Granular soils should be placed in loose lifts 6 to 9 inches thick and compacted from -2% to +3 percentage points above their optimum moisture content. Use of very granular free-draining soils (coarse sands, sand/gravel mixtures, or gravel) which could trap and hold water in utility trenches should be avoided in areas where the surrounding soils are predominately clay materials.' 91-586 -19- Bore Tunnel Excavations From Sta. 38+50 to Sta. 39+95, plans are to bore beneath the existing St. Louis and Southwestern Railroad embankment and the adjacent creek. This tunnel boring will also pass beneath an existing 6-inch diameter gas pipeline and open drainage trench that runs parallel to the railroad alignment. Based on the conditions encountered in Borings B2-8 and B2-9, the tunnel bore will generally be in shale, with very little or no shale cover above the tunnel crown. The soils immediately above the shale in this vicinity consist primarily of sandy clays near Boring B2-8, and shaly clays overlain by sand and gravel in Boring B2-9. The surface contour of the shale between these borings could vary and sections of the tunnel may have little or no shale cover, and may penetrate into the upper clays and sands. Seepage was encountered above the sewer level and dewatering would be required to bore the tunnel excavation under dry conditions. The borings indicate water is present in the sandy soils above the shale, and tunnel excavations that encounter these sands could cause undermining of the railroad embankment and rupturing the 91-586 -20- gas main, particularly if the tunneling excavation encounters the overlying wet sand strata. Additional borings in this area are recommended beneficial to further define the amount of shale cover through the bore section if microtunneling is used. Adjustments in the tunnel elevation should be considered to avoid possible construction problems. Access will be somewhat limited due to the existing railroad track in this embankment section. LIMITATIONS AND REPRODUCTIONS The foregoing recommendations are based on analyses of the soils from each of the indicated borings with the assumption of uniform variation in the soil properties between borings. Should any conditions at variance with this report be encountered during construction, this office should be notified immediately so further investigations can be made and supplemental recommendations can be given. 91-586 -21- The reproduction of this report, or any part thereof, supplied to persons other than the owner, should indicate that this study was made for foundation design and trench safety purposes only and that verification of the subsurface conditions for purposes of determining difficulty of excavation, trafficability, etc., are responsibilities of others. This report should not be used as a construction specification but as a guide for developing final foundation and excavation plans and specifications. Analysis performed by: Clement B. Bommarito, P.E. 91-586 -22- APPENDIX TABLE 1 OBSERVATION WELL READINGS GRAPEVINE CREEK SEWER TRUNK MAIN COPPELL, TEXAS Depth Depth Depth Depth Depth Well to water to water to water to water to water No. 2/14/92 2/18/92 3/23/92 6/22/92 6/24/92 B2-8 ........ 14.0 B2-9 13.5 13.5 13.5 14.0 - - Groundwater conditions during drilling: - B2-8: Seepage at 11.5,' Water at 16' at~-completion on 4/16/92 - B2-9: Seepage at 12.5' Water at 17' at completion on 2/10/92 SLOPING BENCHING CONFIGURATIONS SIMPLE SLOPE COMPOUND SLOPE IN ,_. LAYERED SYSTEM MAX. ALLOWABLE / /_~._jv LAYER .... SLOPE ~ / , .... //~v . =,~ ,'- v LAYER 2 H_JV LAYER MULTIPLE BENCHES COMPOUND PROTECTION MAX. ALLOWABLE / ~ , ~ SLOPE FOR NATURAL / ~.3 MAX. ~V '- CLAY, CLAY OR I ~1 ~ '~'-~ GRANULAR FILL OR ~- , MAX. WEATHERED L ~.5TM, __ SHALE / ' 3' MAX. SHALE SUPPORT OR 2 "-- SHIELD SHALE SYSTEM J MAXIMUM ALLOWABLE SLOPE (H'V) SOIL/ROCK TYPE 12 FEET OR LESS 12-20 FEET 21 -30 FEET CLAY FILL 1:1 1.5:1 1.75:1 GRANULAR 1.75:1 2:1 2.25:1 NATURAL CLAYS OR 0.75:1 1:1 1.25:1 WEATHERED SHALE SHALE 0.5:1 0.5:1 0.5:1 .- NOTES: 1. NO EQUIPMENT OR SPOIL NEARER THAN 3 FT. WHICHEVER IS GREATER. TO THE TOP OF SLOPE. SOUTHWI~STERN LABORATORIE~I 2. ASSUMES ABSENCE OF GROUNDWATER. SEEPAGE CAN REQUIRE ADJUSTMENTS IN I FIGURE 1 THE SLOPE ANGLES AND I OR DEWATERING. 3. No SLOPE EXPOSED FOR MORE THAN 72 HOURS. DESIGN ILLUSTRATION 4. FIELD OBSERVATIONS BY A QUALIFIED UTILITY- TRENCH OPEN CUT GEOTECHNICAL ENGINEER REQUIRED. CONFIGURATIONS 5. ASSUMES MAXIMUM OVERBURDEN SOIL SLOPE HEIGHT OF $0 FT. GRAPEVINE SEWER TRUNK MAIN- PHASE II i SWL 91 - 586 COPPELL. TEXAS 6-16-9'Z SURCHARGE (ASSUME 2') TOP OF SUPPORTED ~ A. AVERAGE CONDITION. ADJACENT TERRAIN GENERALLY FLAT AND NOT STEEPER THAN 5 hor.: 1 vert. BANK ...._~~ _ / p--40(H+2) · H BOTTOM OF EXCAVATION~ SURCHARGE / CREEK EMBANKMENT //~ I p =40 He He=H(1 +2vlh) ~'H( 1 + 0.04,'_.A ) or He=H~ +2 H WHICHEVER IS LESS Y- x,. ~L~_~ C. HEAVY SURCHARGE p=40(H+Hq)+Pq W (I-0.6 x 0.8W Hq pq= _~ < . H(,t+x) H' - H(,f+x) Pq CAN BE DISREGARDED WHEN x~_H ¥ | p / ~:- ,~- LENGTH OF EQUIPMENT OR LINE LOAD ~~ ~ IN THE DIRECTION OF THE TRENCH .... W = TOTAL FORCE EXERTED BY WEIGHT OF EQUIPMENT OR LINE LOAD NOTES: 1. NO EQUIPMENT OR SPOIL NEARER THAN 3' OR ONE-HALF THE DEPTH OF EXCAVATION, WHICHEVER IS GREATER, TO THE TOP OF EXCAVATION. UNLESS SYSTFM IS DESIGNED FOR SURCHARGE LOADS. 2. IF WHEEL SPACINQ IS WIDE, pq SHOULD ALSO BE CHECKED FOR DISTANCE x ,. DISTANCE FROM EDGE OF EXCAVATION TO CLOSEST WHEEL AND W = WEIGHT SUPPORTED BY CLOSEST WHEEL. 3. A SSUMESABSENOEOFHYDROSTATIC PRESSURE. GROUNDWATER ~ ~,~"J~W/ MAY REQUIRE ADDITIONAL BRACING OR DEWATERING. SOUTHWESTERN LABORATORIES FIGURE 2 4. CONTINUOUSpERSONNEL REQUIRED.OBSERVATIONS BY QUALIFIED GEOTECHNICAL EARTH PRESSURESFOR TEMPORARY BRACED OR 5. H IN FEET. TIED BACK SHORING GRAPEVINE SEWER TRUNK MAIN- PHASE II B. BASED ON A MAXIMUM DEPTH, H OF 30 FEET. COPPELL. TEXAS SWL 91 - 586 A-3 NOTE -' BORING NO. B2- I THRU B2-4 NOT DRILLED. ORIGINAL ALIGNMENT ~PROPOSED 16+15 ~ SEWER TRUNK MAIN~ ;B2-5 A. 34 ~ 27 B2-9 STA. 41+35 STA. 48+a0(~ COPPELL ROAD NOTE: BORING LOCATIONS ARE APPROXIMATE PROdECT I TITLE PROPOSED GRAPEVINE CREEK SEWER TRUNK MAIN BORING LOCATION DIAGRAM COPPELL, TEX~S SWt. 91 - 586 SCALE: 1' = 450' + / - DATE: 61 231 92 DRAWN BY: CD A-4 Figure 3 40+10 B2-9 STATION 48+20 43+ 15 BORIN6 B2-11 B2-10 GROUND SURFACE 510 - ~ (~ 10+50 AT BORING LOCATION (~) (TYPICAL) B2-2a -- 36+00 18+O0 · -- B2-8 23+00 B2-5 5oo-® ® ~- B2--6 ® B2-7 6+45 B2-1 A .- COMR 470 - FIGURE 4 SOIL & SHALE STRATIGRAPHY GRAPEVINE CREEK SEWER TRUNK MAIN PHASE II COPPELL, TEXAS SWL 91 - 586 LOG OF BORING PROJECT: Grapevine Creek Sewer Trunk Main-Phase II BORING NO.: B2-1A CLIENT: Ginn and Case, Inc. LOCATION: Coppell, Tx. DATE: 5-12-92 TYPE: Sample CASED TO: GROUND ELEV: ~ i ~ 9 Caved at 17.0' and water at 11.0' on 5-13-92. Asphaltic Concrete (4") on tan , and gray broken limestone 10 30 15 15 .. ~ with tan clay (FILL) 8 52 7 i 26.4 ~ Bro~ sandy CLAY (CL) with ................................................................ , --~ ~ ~bedded pebbles . ~ Tan clayey S~(SC) ~l - Tan and gray shaly C~Y (CH) ; -with gray clayey shale I 50 15 '& Gray S~LE ~ Boring terminated at 20.0' 25 ~ ," - .......................................... ~ .................... 30 2 I I 45q I 91-586 A-6 SOUTHWESTERN ~BORA TORIES INC. LOG OF BORING PROJECT: Grapevine Creek Sewer Trunk Main-Phase II BORING NO.: B2-2A "- CLIENT: Ginn and Case, Inc. LOCATION: Coppell, Tx. DATE: 5-12-92 TYPE: Sample CASED TO: GROUND ELEV' l[' SeepaEe enc°untered at 23'0'' ~1m9 caved at 23.0' on 5/13 T. X Asphaltic c°ncrete (4''); / ' --] 15 ~ tan and gray broken)LIMESTONE --~ with tan clay (FILL 11 126 32 15 ~ 17 ~19,460 3.5 Bro~ and reddish-brown sandy __L4 ........... 4Q .... 22___:__~ .............................. "- ~ ~ Bro~ and gray sandy C~Y (CL) with iron ore pebbles _. Tan and light gray sandy ~ I C~Y (CL) with iron stains i 8 : ~ 4 15 ' -- Tan clayey SA~ (SC) .................................... ; ........................... i ' { ~ ' - X 23 "- : ~' 17 ~!l i~ Tan and gray shaly CLAY (CH)' -- i , ~ i --~ ~ 100 Gray S~LE 30 ~ .4" I --11 ~: Boring terminated at 32.0 ' ~ , I , 35 ' , 40 ............... 2 ............................................... , LOG OF BORING PROJECT: Grapevine Creek Sewer Trunk Main-Phase II BORING NO.: B2-5 CLIENT: Ginn and Case, Inc. LOCATION: Coppell, Tx. DATE: 4-16-92 TYPE: Sample CASED TO: GROUND ELEV: ~ -~: m Seepage encountered at 16.0~; ~ ~ ~ ~ < i ~ dry at completion; dry 5 hours = ~ ~ ~ 8 ~ !ml O after completion. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ I[ Bro~ sandy C~Y (CL) 6 i Tan S~ with gravel and ~ ' ' ~ 10 occasional clayey sand seams (SP) 10 5 ........................................... i .................... II ,, ~. [ I i : I : ............................................................. -' ~ 21 ~ ~ i , ~ · t~ , ,. , m Tan and gray silty sandy C~Y (CL) ~ ~ i , ~ - m ~ ............. ~ ................................................. 17 ~ : ?~n and bso~ C~T ~ith inte~bedded , ~ ~ --~ m sandy Bsavel seams (C~) ~ ~ = ~ m ~0 ~ ~ ....... s ...... ...... ~ .................................... ...... I ' 50 Gray S~LE ~ ,~ I Boring t~rminated at 23.0~ i ., 25 ~ ~.-. ................................... ~ ........................... i l ...... ~ .....................~ .......................... ~ 30~ I i I -- 35 ~ ............................................................... 40 .............. " ................................................. ' 45 .......................................................... ~ ...... PROJECT NO. : 91-586 A-8 SOUTHWESTERN ~BORATORIES LOG OF BORING PROJECT: Grapevine Creek Sewer Trunk Main-Phase II BORING NO.: B2-6 CLIENT: Ginn and Case LOCATION: Coppell, Tx. DATE: 4-16-92 TYPE: Sample CASED TO: GROUND ELEV: Dry at completion; dry ten ':~ ~ ~ g ~" ~ minutes after completion. ~ : 0 ~~ Dark bro~ sandy C~Y (CL) with ~, iron ore pebbles ~ Bro~ silty C~Y (CL) with iroq ore pebbles / 14 119 42, 18 24 ' 6,740 7.3 5~ ,. Gray silty C~Y (CL) with ................................................................ ~ ~ calcareous nodules and iron ore ~ pebbles 10~ : Tan and gray clayey S~D (SC) ....... ] ....................................................... ~ ~ with sand and gravel seams !4~ 35.1 50 ................................................................. --,. ~ Boring terminated at 21.0' 30 ............................................ i 35 ............... 40 ......................................................... . ...... 45 ~ ....... 4 ...... ~ ................................................. ~, PROJECT NO. ' 91-586 A-9 SOUTHWESTERN ~BORATORIES INC. LOG OF BORING PROJECT: Grapevine Creek Sewer Trunk Main-Phase II BORING NO.: B2-7 CLIENT: Ginn and Case, Inc. LOCATION: Coppell, Tx. DATE: 4-16-92 TYPE: Sample CASED TO: GROUND ELEV: - ~ ~ Grayish-brown, lisht bro~ and , ~ yellowish-brown C~Y and sandy 20 'i105 ~ ~ : ; ~ clay with Eravel and broken --i shale 19 ~ 95 · ; '. 8,000(P)~ : 13 Tan S~ with gravel (SP) 7 --! ~ 50 Brown C~Y with interbedded Boring terminated at 14.0' I 25 ~ .. - ................................... : ........................... I , 40 .................................... ~ ~ ........................... PROJECT NO. : 91-586 A-10 SOUTHWESTERN ~BORATORIES INC. LOG OF BORING PROJECT: Grapevine Creek Sewer Trunk Main-Phase II BORING NO.: B2-8 CLIENT: Ginn and Case, Inc. LOCATION: Coppell, Tx. DATE: 4-16-92 TYPE: Sample CASED TO: GROUND ELEV: ~ O ~ GROUNDWATER INFORMATION ' ~ : ~ ::~ ~ Seepage encountered at 11.5'; ~ : ~ '~ ~ Water at 16.0' at completion --~~1 Dark, grayish-brown sandy C~Y(CL)~ 18 110 30 ; 19 I 11~:9'000+(P~ ~ Gray and tan C~Y with iron ore ~ ~ and calcareous nodules (CH) 17 ~116 53 ~ 19 ~ 3~1 '6,140 7.6 10 Tan and gray sandy C~Ywith .................... [ ....... [ ...... 7 ........................... tan clayey sandy seams (CL) " ~ Gray S~LE ~ 50 Boring terminated at 17.0' 20 ' ' ............................................................... ~ ' , ~ I ' I --. 35 ......................................................... ] ...... I i 45 ~ ' ...... % ............. ~ ....... ~ ............. ~ .................... , PROJECT NO. ' 91-586 A- 11 SOUTHWESTERN ~BORArORfES INC. LOG OF BORING PROJECT: Grapevine Creek Sewer Trunk Main-Phase II BORING NO.: B2-9 CLIENT: Ginn and Case, Inc. lOCATION: Coppell, Tx. DATE~-10-92 TYPE:Auger CASED TO: GROUND ELEV: - ~ O z Brown clayey S~ with 16 46.0~ ~imestone gravel (FILL) ~ 16 42 19 23 5-~ I~ siltyDark brown,c~y andbr°~sandyand claygray with .............................................................. ~ ~ gravel, iron oro pebbles, -' ~ broken rock, shells and sand 10 pockets (Fill) Tan silty S~ and gravel (SH) 20~~ ~2" ~Tannish(cL) brown silty shaly CLAY~ ..................... ~ ....... [ ...... . ............................ '- 1" Gray S~LE 25 ~ ~00 1 Boring torminated at 25.0~ aO ............................................ [ .................... 35 ..................................... [ ........................... 40 .......................................................... ~ ...... 45 ........ ~ ...... 4 ...... ~ ........................................... . . i LOG OF BORING PROJECT: Grapevine Creek Sewer Trunk Main-Phase II BORING NO.: B2-10 CLIENT: Ginn and Case, Inc. LOCATION: Coppell, Tx. DATE: 2-11-92 TYPE: Auger CASED TO: GROUND ELEV: Q ~ ~ S at completion ~ ~ ~ ~ ~ ~ 8 Dark brown C~Y and tan silty 117 calcareous nodules wSth I limestone fragments 19 103 29 16 13 5-- i Brown, tan and gray sandy clay ............................................................... to clayey SAND with occasional 8 Bravel (Fill) 15 ~ Brown and gray clayey S~D (SC) · an~sh b~o~ cZa~eF ~with gravel (SC) 15- ~ 30 ~ ~Tan coarse SA~ with gravel ~ .......................................... ' ..................... _ ~" rown and gray shaly C~Y 20- ~oo ~CH) ................................................................ Dark gray S~LE ~ ............................................................... Boring terminated at 28. ~0 ................................................................. ! I I ' 40- : ............................................................... 45 'd ................................................................ ' ! i PROJECT NO. : 91-586 A- 13 SOUTHWESTERN LABORATORIES INC. LOG OF BORING PROJECT: Grapevine Creek Sewer Trunk Main-Phase II BORING NO.: B2-11 CLIENT: Ginn and Case, Inc. LOCATION: Coppell, Tx DATE: 3-9-92 TYPE: Sample CASED TO: GROUND ELEV: ~ SeepaEe encountered at 13.0'; 7.0' omp e o.. Dark bro~, brown and tan ' and silty, clay ~ith 15mestone 19 102~ cebbles (CH-CL) ~ , Grayish tan C~Y with trace to 22 · ~ 60 j 23 I 37 ~ '6,500(P) 5-- . little sand (CH) ............................ ~ ...... r ........................... ' Tan and gray sandy C~Y to :, clayey S~D (CL-SC) : , 9,000+(P) 10~ . ~ .......................................... ~ .................... --~, ~ Tan silty S~ with small pea .i ~ ~ 16 gravel (SM) . 15 ~ .............. ~ ...... ~ ....... ~ ......~ ........................... ', Boring terminated at 18.0' 45 ~ GRAIN SIZE DISTRIBUTION U.S. Stand~rd Sieve Openlngi In Inchei U.S. :Standard Sieve Number~ I-h/drometer lOO ', ' '"' r, ,_ ,~~...,., ,,, ,,, ...o, "', '" '", '"", '"', '"", "°, o 90 - ~ 10 ~ 80 20 ,"' .? ~ 70 30 ..~ 60 40 -- 50 5O .- > m 40 60 n,- I m 20 80 10 90 0 5 2 5 2 ~ 2 ~ 2 ~ 2 100 100 10 1 0.1 0.01 0.001 Grain Size in Millimeters G RAVE L SAN D I Coorse I Fine CoorseI Medium I Fine SILT or CLAY I SYMBOL BORING DEPTH SOIL DESCRIPTION ~ B2-5 3.5-5' Tan Sand SwL 92-586