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Home My WebLink AboutCDP 02-42; 2200 HIGHLAND DR; UPDATE TO GEOTECHNICAL INVESTIGATION; 2003-10-01I I I I I I I I I I I I I I ·I I I I I Plan Review Geotechnical Update Report Lot at the North Terminus of Highland Drive Carlsbad, California (A.P.N. #156-051-24) HDP ();2.-ID October 1, 2003 RECEIVED Prepared For: MR. JIM DUNN, JR 4316 Cassanna Way, #305 Oceanside, California 92057 Prepared By: OCT O 6 2003 CITY OF CARLSBAD PLANNING DEPT. VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Suite 102 Escondido, California 92029 Job #03-387 -P I I I I I I I I I I I I I I I I I I I TABLE OF CONTENTS PAGE NO. I. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 II. SITE DESCRIPTION / HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Ill. PROPOSED DEVELOPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 IV. GEOTECHNICAL CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 A. Slope Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 8. Seismic Response Coefficients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 V. CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 VI. RECOMMENDATIONS ......................................... ~ . . . 6 A. Remedial Grading and Earthworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 B. Foundations and Interior Floor Slabs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 C. Exterior Concrete Slabs / Flatworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 D. Soil Design Parameters .... _. ... ~-. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 E. Asphalt and PCC Pavement Design .............................. 15 F. General Recommendations ............... •. . . . . . . . . . . . . . . . . . . . . . 16 VII. LIMITATIONS ................................................... 18 TABLE NO. Site Seismic Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 PLATE NO. Regional Index Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Site Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Cross-Section at Proposed Storm Drain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Geologic Cross-Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Typical Slope Rec_onstruction Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Test Boring and Test Pit Logs ........................................ 6-14 Retaining Wall Drain Detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Isolation and Re-entrant Corner Reinforcement . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Slope Reinforcement Installation Guide ........................ APPENDIX A I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT LOT AT THE NORTH TERMINUS OF HIGHLAND DRIVE CARLSBAD, CALIFORNIA I. INTRODUCTION _ The property investigated in this work includes 2.54 acres of undeveloped land located at the northern terminus of Highland Drive within the City of Carlsbad. The property location is depicted on a Regional Index Map included herein as Plate 1. Existing topographic conditions and proposed development at the site are shown on a Site Plan, Plate 2. A storm drain pipe traverses the property transporting storm water from an inlet box at the northend of Highland Drive into canyon terrain and the Buena Vista Lagoon to the north. The storm drain is buried within a descending slope which marks the northern margins of the property. The existing pipe has failed and resulted in high levels of erosion and related failures within lower slope terrain. We understand that the u·pper nearly level areas atop the existing project descending slope is planned for the support of a single-family residence to the east and a detached garage/shed structure to the west. Consequently, The purpose of this work was to review all available pertinent geotechnical reports and documents and provide update recommendations that are consistent with the proposed site development. Previous soils and geotechnical investigations at or in the vicinity of the study property have resulted in the following technical reports: 1. "Preliminary Geotechnical Report, Storm Drain Reconstruction, North End of Highland Drive, Carlsbad," Job #03-262-P, prepared by Vinje & Middleton engineering, Inc., dated June 17, 2003. 2. "AssE?ssment of Fill Slope Regression, 2202 Highland Drive, Carlsbad, California," prepared by Taylor-Hunter Associates, Inc., THA Project No. G02-00199, dated December 5, 2002. 3. "Geotechnical Investigation, Proposed Lot Split, Three-Acre Site, 2022 Highland Drive, Carlsbad, California," by Ron Gutier (C.E.G.) and Erik J. Nelson (P.E.), Job #GN-1, dated February 17, 1989. The referenced reports are on file wit_h our firm and copies can be obtained upon request. Logs of the exploratory Test Borings and Test Pit Trenches completed in connection with the preparation of the 1989 investigation (Reference 3) are enclosed herein as Plates 6 through 14. Boring and trench locations are shown on the enclosed Site Plan, Plate 2. VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD II. SITE DESCRIPTION / HISTORY PAGE 2 OCTOBER 1, 2003 The irregular-shaped parcel is located at the north terminus of Highland Drive in a residential section of the City of Carlsbad. The property currently supports a moderate covering of native plants and weeds. Site topography ranges from nearly level in the upper southeasterly reaches of the property to steeply sloping, and locally vertical, canyon terrain within the northwestern margin of the property with more than 50 feet of vertical relief. Slope gradients at and adjacent the study property generally approach 2: 1 to 1: 1 (horizontal to vertical). Existing site topography was achieved by placing undocumented fills atop natural ground surfaces more than 36 years ago (Reference 3). Approximate fill limits as determined in the field is shown on Plate 2. Site existing fills, as outlined in Reference 3, consist of silts and sands with a considerable amount of deleterious material and no evidence of benching into bedrock. We understand that plans for reconstruction of the failed storm pipe within the lower reaches of the northern descending slope are near completion. We further understand that the City of Carlsbad is planning to carry out the storm drain repairs and realignment with the associated grading repairs of lower canyon terrain erosion resulting from the pipe failure. Ill. PROPOSED DEVELOPMENT As depicted on Plate 2, a new residential dwelling with detached garage and associated improvements are planned for the upper reaches of the subj~ct property. Moderate to significant grade alterations using cut-fill grading techniques are proposed to achieve design grades and construct level surfaces for the support of the planned structures and improvements. The planned grade alterations primarily consist of minor cutting of the higher areas to the southwest and placing fills over the existing northern slope to new design configurations. Modular (sequential) retaining walls are also incorporated into the designs to accommodate ground level transitioning and allow 2: 1 slope gradients. The existing 24-inch storm drain pipe crossing the site will be abandoned and replaced with a 36-inch pipe installed along a new alignment. The new alignment extends from the lower terrain over the ascending slope and crosses the project property to the existing inlet box north of Highland Drive as shown on Plate 2. The storm drain installation will be performed as a part of the City of Carlsbad storm drain reconstruction project which also includes reconstruction of the failure scrap within the lower slope terrain. New storm drain profile with respect to existing terrain ·and proposed grading is depicted on the enclosed Cross.:section at Proposed Storm Drain, Plate 3. VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION l'ERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I· I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD PAGE 3 OCTOBER 1, 2003 Construction details are unknown. However, it is anticipated that conventional wood-frame and stucgo buildings supported on shallow stiff continuous strip and spread pad concrete footings with slab-on-grade floor foundations will be utilized. IV. GEOTECHNICAL CONDITIONS Geotechnical conditions at the site remain substantially unchanged since the preparation of the referenced reports. The study property is underlain by Formational rock units that range from Pleistocene age Terrace Deposits at the near surface to Eocene age sandstone units at depth (Reference 3). Project slopes are mantled by an undetermined thickness of undocumented fills. The upper, southeast portion of the property consists of nearly level terrain that gives way to steep canyon topography to the northwest. A subsurface profile as determined from available geotechnical data is depicted on the enclosed Geologic Cross-Section, Plate 4. A. Slope Stability Site topographic conditions are depicted on Plate 2. Near vertical slope conditions mark the lower canyon terrain where a recent storm drain failure has occurred. No indications of deep-seated instability were noted; however, rotational-type slope failures within the existing lower near-vertical slopes may be expected under current site conditions. We understand the City of Carlsbad is developing plans for the replacement of the storm drain and repair grading of the lower slope failure areas within the impacted areas. The existing northern embankment is a fill over natural slope type construction. The embankment was created by placing undocumented fill deposits over the pre- grading _sloping natural terrain. The fills were placed without engineering observation and compaction testing control. It is reported that lower keyways or adequate benching of sloping ground receiving fill were also not provided. Furthermore, existing fills are generally loose deposits and contain trash and organic debris. Based on the available information, the existing northen graded fill slope is considered marginally stable (low safety factor) and subject to failure upon saturation, surcharging or a significant seismic event. B. Seismic Response Coefficients For design purposes, site specific seismic parameters were determined as part of this investigation in accordance with the Uniform Building Code. The following parameters are consistent with the indicated project seismic environment and may be utilized for project design work: VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD PAGE 4 OCTOBER 1, 2003 TABLE 1 ... .. •. s~1~mic-. aeismic; Response Coefffcients Site :Soil. • • -aeisinic: Profile -Seismic '. · Zone~· _ ~~,µrce. :_ -N~ I Nv-,. : Ca:'.·,·J.· .:_o~::.:--1---: :.Ts : : --1· TY:pe-Zon~ F~~tdi<· --.-.·Type ,. T.9 ' '; -•. ' . ' ', , .. -'. ' I SD I 4 I 0.4 I B I 1.0 I 1.1 I 0.44 I 0.68 I 0.614 I 0.123 I Accordinq to Chapter 16, Division IV of the 1997 Uniform Buildinq Code. V. CONCLUSIONS Based upon our review of the referenced technical reports and recent site inspection, development of the property for residential purposes, substantially as proposed, is considered feasible from a geotechnical viewpoint. The site is underlain by loose undocumented fills within_ the pad and northern slope areas over Formational sandstone units which are exposed in an overly steepened slope condition within the lower terrain below the proposed building areas. Geotechnical factors presented below are unique to the project site and will influence grading procedures and the associated development costs: * A recent storm drain failure in the lower slope areas below the property has resulted in high levels of erosion and near vertical slopes. The lower slope failure has not yet impacted the upper graded slope along the project northern boundary. However, future local impacts within the existing storm drain alignment is considered likely, particularly in an event of heavy rainfall. * Existing slope areas of the property were developed by placing loose undocumented fills over sloping natural terrain. The fills also contain an abundance of trash debris and deleterious materials (Reference 3). The northern slope is marginally stable and should be removed and properly reconstructed as recommended in following sections. • * The replacement of the storm drain and repair grading of the lower slope failure within the impacted areas are planned by the City of Carlsbad. The new storm drain alignment crosses the property as shown on Plate 2. The remaining portions of the existing pipe at the project site should also be removed as part of the site remedial grading and/or appropriately abandoned per the approved plans. VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD PAGE 5 OCTOBER 1, 2003 * Site existing fills and upper weathered Terrace Deposits/Formational rock are not suitable for support of planned structures and improvements in their present condition. The entire section of existing fills, topsoils and upper weathered Terrace Deposits/Formational rock should be removed and properly recompacted using remedial grading techniques as recommended in a following section. Added excavations of cut ground will be required in the case of cut/fill pads in order to eliminated non-uniform bearing soils transitioning. * The overall stability of graded building surfaces developed over sloping terrain is most dependent upon adequate keyjng and benching of fills into the undisturbed bedrock during grading operations. At the project site, added care should be given to proper construction of keyways and benching during regrading. * In general, reconstruction of the northern slope and regrading of the site to design elevations may be considered difficult overall. Portions of the project regrading and reconstruction within the storm drain alignment may be coordinated wi_th the City · of Carlsbad, a_nd installation of the new drain pipe. Proposed modular transition walls near the lower slope areas may also be difficult to construct due to necessary deepened foundations for setback requirements and adequate clearance from t_he top of the new storm drain pipe to bottom of the wall foundations. Appropriate recommendations are given in the following sections. * Import soils, if required to complete grading and achieve final design grades, should conform to the requirements of this report as specified in the following sections. * Finish grade soils are expected to consist of sandy deposits (SP/SM) with very low expansion potential (El less than 21). Actual classification and expansion characteristic of finished grade soil mix can only be provided in the final as-graded compaction report based on appropriate testing. Final foundation and slab subgrade soils should be tested at the completion of pad construction to confirm expansion characteristics of bearing soils which will govern final foundations and slab design. * Adequate site surface, subsurface and slope face drainage control are critical factors in the future stability of the developed property as planned. Drainage facilities should be designed and installed for proper control and disposal of surface and subsurface water. * Liquefaction and seismically induced settlements will not be a factor in the development of the project site provided our remedial grading recommendations are followed. VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADlNG SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD PAGE 6 OCTOBER 1, 2003 * Post construction settlements are not expected to be factors in the construction of ··the planned buildings at the project site provided our remedial grading and foundation recommendations are implemented during the construction phase of the project. * Soil collapse will not be a factor in the constructions of the planned buildings at the study site provided our recommendations are followed. VI. RECOMMENDATIONS The following recommendations are consistent with the indicated geotechnical conditions. at the project site and should be reflected on the final plans and implemented during the construction phase. Added or modified recommendations may also be appropriate and can be provided at the final plan review phase: A. Remedial Grading and Earthworks Cut/fill and remedial grading techniques may be used in order to achieve final design grades and construct a stable ground for supporting the planned structures and improvements. All grading and earthworks should be completed in accordance with Appendix Chapter 33 of the Uniform Building Code, City of Carlsbad Grading Ordinances, the Standard Specifications for Public Works Construction, and the requirements of the following sections wherever applicable: 1. Clearing and Grubbing -Remove surface vegetation, trash, debris and other unsuitable/deleterious materials from all areas of proposed new fills, improvements, and structures plus 10 feet minimum, or as directed in the field. The prepared ground should be inspected and approved by the project geotechnical engineer or his designated representative. All irrigation lines, abandoned pipes and undergrounq structures should be properly removed from the construction areas. Existing underground utilities in the construction areas Should also be pot-holed, identified and marked prior to the actual work. Inactive lines should be properly removed or may be abandoned as approved in the field. Voids created by the removals of the underground pipes or structures should be properly backfilled with compacted fills as recommended herein. 2. Removals and Remedial Grading -Remedial techniques should be used in order to construct safe and stable ground and building pad surfaces suitable for the support of the proposed structures and improvements. The entire section VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION l'ERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD PAGE 7 OCTOBER 1, 2003 of existing site fills, topsoils and weathered soft sandstone units in the areas to receive new fills, structures and improvements plus 10 feet where possible, and as directed in the field should be removed to the underlying competent bedrock and placed back as properly compacted fills. Actual limits and depths of removals should be given in the field by the project geotechnical consultant. However, approximate depths may be obtained from the enclosed Test Borings and Test Pit Logs (Plates 6-14). Project grading operations may be coordinated with the City of Carlsbad_ to concur with the lower slope repairs of the impacted areas, as well as the planned trenching and new storm drain installation within the proposed realignment. 3. Cut-Fill Transition / Undercuts -Ground transition from excavated cut to placed fill should not be permitted underneath the proposed structures and improvements. Building foundations and floor slabs should be uniformly supported on undisturbed cut ground or entirely founded on compacted fills. Transition areas will require special treatment. The cut portion of the cut/fill pads plus 10 feet should be undercut to a sufficient depth to provide for a minimum of 3 feet of compacted fill mat below rough finish grades, or at least 12 inches of compacted fill beneath the deepest footing whichever is more. In the roadways, driveway, parking and on-grade slabs/improvement transition areas there should be a minimum of 12 inches of compacted soils below rough finish subgrade. 4. Fill Materials and Compaction -Soils generated from the excavation of site weathered sandstone will predominantly consist of good quality sandy materials which will work well in compacted fills. Soils generated from the removals of the project existing fills will include trash debris and deleterious materials. All trash debris and deleterious material should be selectively separated from the existing project fills to the satisfaction of the project geotechnical consultant prior to reuse as new site fills. Separated trash debris and unsuitable materials should be properly removed and exposed of. Clay bearing soils, if encountered,-should be selectively buried in deeper fills at a minimum of 4 feet below rough. finish pad grades and 15 feet away from the finish slope face. Project new fills shall be clean deposits free of vegetation, organic matter, deleterious materials, trash and debris consisting of minus 6-inch particles as approved in the field. • Uniform bearing soil conditions should be constructed at the site by the grading operations. Site fills should be adequately processed, thoroughly mixed, moisture conditioned to near optimum moisture levels as directed in the field, VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD PAGE 8 OCTOBER 1, 2003 placed in thin uniform horizontal lifts and mechanically compacted to a minimum of 90% of the corresponding laboratory maximum dry density per the ASTM D-1557, unless otherwise specified. . . 5. Shrinkage and Import Soils -Based upon our analysis, on-site soils may shrink approximately 5% to 15% on volume basis when compacted to a minimum of 90% compaction levels. Import soils, if required to complete repair grading or achieve final design grades, should be clean sandy deposits ( expansion index less than 21) and approved by the project geotechnical engineer prior to delivery to the site. Non-expansive sandy import soils, if any, should be used for wall backfills and placed within the upper finish subgrade levels. 6. Reconstruction of Existing Slope and New Graded Slope -The existing northern fill slope should be removed and reconstructed as a part of the project remedial grading operations in accordance with the requirements of this report. Slope reconstruction is depicted on the enclosed Typical Slope Reconstruction Details, Plate 5. The new reconstructed fill slope shall be provided with a lower keyway. The keyway should maintain a minimum depth of 2 feet into the competent bedrock with a minimum width of 20 feet as approved by the project geotechnical engineer or his designated representative. The keyway should expose competent bedrock throughout, with the bottom heeled back a minimum of 5% into the natural hillside and inspected and approved by the project geotechnical engineer. Additional level benches should be constructed into the natural hillside as the fill slope construction progresses·. The slope should be reconstructed to achieve existing and/or flatter slope design gradients. Provide slope reinforcement consisting of Tensar UX-1400 (or greater from the same series) at approximately 4 vertical feet for slope gradients steeper than 2:1 as shown on the enclosed Plate 5. Slope reinforcement should be placed 1 ½ feet from the finish slope face to the back side heel of excavated benches within the compacted embankment fills for additional stability. Intermediate slope face reinforcement consisting of Tensar BX-1100 (or greater from the same series), should be provided to enhance surficial stability as shown. Slope reinforcement shall be placed in conformance with the enclosed Slope Reinforcement Installation Guide enclosed herein as Appendix A. Reconstructed slopes should be compacted to a minimum of 90% of the corresponding laboratory maximum density value in accordance with ASTM D- 1557 out to the slope face. Back rolling at a minimum of 4-foot vertical VINJE & MIDr:>LETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I 1. I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD PAGE 9 OCTOBER 1, 2003 increments and track-walking the completed slope is recommended. Field density tests should be performed to confirm adequate compaction levels within the slope face. New project graded slopes should be programmed for 2:1 gradients maximum. Graded slopes constructed at 2:1 gradients will be grossly stable with respect to deep seated and surficial failures for the anticipated design maximum vertical heights. All fill slopes shall be provided with a lower keyway as specified, and compacted to 90% (minimum) of the laboratory standard out to the slope face. Cut slopes should ·be inspected and approved by the project geotechnical consultant during the grading to confirm stability. In the event loose existing fills/topsoils are encountered at the cut surfaces or portions thereof, the impacted slope face may require reconstruction as stability fill slope or the slope face may be moisture conditioned and compacted in-place by track- walking with heavy construction equipments. Specific recommendations should be provided by the project geotechnical consultant in the field based on actual cut slope face exposures. 7. Wall Back Drainage -A wall back drainage system should be provided behind all project retaining walls. The wall back drainage system should consist of a minimum 18-inches wide trench excavated to the depths of the wall foundation level w~th a minimum 4-inch diameter, Schedule 40 (or SOR 35), perforated pipe surrounded with a minimum 2.25 cubic feet per foot of ¾-crushed rocks wrapped in filter fabric (Mirafi 140 N), or Caltrans Class 2 permeable aggregate installed at suitable elevations to allow for adequate fall via a non-perforated solid pipe to an approved outlet. Protect pipe outlet as appropriate. Filter fabric can be eliminated if Class 2 permeable material is used. Typical wall back drain system is depicted on the enclosed Plate 15. Provide appropriate waterproofing as indicated on the approved project drawings. 8. Storm Drain Trenching and Backfilling -All trenching and backfill operations associated with the new storm drain installation should be completed as specified in the "Preliminary Geotechnical Investigation, North End of Highland Drive," prepared by this office, Job #03-262-P, dated June 17, 2003 (Referertce 1), and subsequent Grading Plan Review letter, dated October 1, 2003. The referenced report and plan review letter should be considered and utilized in conjunction with this report where appropriate and applicable. VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD PAGE 10 OCTOBER 1, 2003 9. Surface Drainage and Erosion Control -A critical element to t~~ continued stability of the building pads and slopes is an adequate surface drainage system and protection of the slope face. This can most effectively be achieved by appropriate vegetation cover and the installation of the following systems: * Drainage swales should be provided at the top and toe of-the slopes per project civil engineer design. * Building pad surface run-off should be collected and directed away from the planned buildings and improvements to a selected location in a controlled manner. Area drains should be installed. * The finished slope should be planted soon after completion of grading in accordance with the project approved landscape plans. Unprotected slope faces will be subject to severe erosion and should not be allowed. Over- watering of the slope faces shall not be allowed. Only the amount of water to sustain vegetation should be provided. Native broad-leaf grasses which require minimal amounts of water to sustain vegetation life are recommended. * Temporary erosion control facilities and silt fences should be installed during the construction phase periods, and until landscaping is fully established as indicated and specified on the approved project grading/erosion plans. 10. Engineering Inspections -All grading operations including removals, suitability of earth deposits used as compacted fill, and compaction procedures should be continuously inspected and tested by the project geotechnical -consultant and presented in the finar as-graded compaction report. The_ nature of finish subgrade soils should also be confirmed in the final compactic;m report at the completion of grading. Geotechnical engineering inspections shall include but not limited to the following: * Initial Inspection -After the grading/brushing limits have been staked but before grading/brushing starts. * Keyway/bottom of over-excavation inspection -After the bottom of over- excavation is exposed and prepared to receive fill but before fill is placed. * Cut slope/excavation inspection -After the excavation is-started but before the vertical depth of excavation is more than 5 feet. Local and CAL-OSHA safety requirements for open excavations apply. VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION l'ERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I. I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD PAGE 11 OCTOBER 1, 2003 * Fill/wall backfill inspection -After the fill/wall backfill placement is started but before the vertical height of fill/backfill exceeds 2 feet. A minimum of one test shall be required for each 100 lineal feet maximum with the exception of wall backfills where a minimum of one test shall be required for each 25 lineal feet maximum. Wall backfills shall also be mechanically compacted to at least 90% compaction levels unless otherwise specified. Finish rough and final pad grade tests shall be required regardless of fill thickness. * Foundation trench inspection -After the foundation trench excavations but before steel placement. * Foundation bearing/slab subgrade soils inspection -Prior to the placement of concrete for proper moisture and specified compaction levels. * Geotechnical foundation/slab steel inspection -After the steel placement is completed but before the scheduled concrete pour. * . Subdrain/wall back drain inspection -After the trench excavations but during the actual placement. All material shall conform to the project material specifications and approved by the project geotechnical engineer. * Underground utility/plumbing trench inspection -After the trench excavations, but before installation of the underground facilities. Local and CAL-OSHA ·safety requirements for open excavations apply. Inspection of the pipe bedding may also be required by the project geotechnical engineer. * Underground utility/plumbing trench backfill inspection -After the backfill placement is started above the pipe zo"ne, but before the vertical height of backfill exceeds 2 feet. Testing of the backfill within the pipe zone, may also be required by the governing agencies. Pipe bedding and backfill materials shall conform to the governing agencies requirements and project soils report if applicable. All trench backfills shall be mechanically compacted to a minimum of 90% compaction levels unless otherwi~e specified. Plumbing trenches more than 12 inches deep maximum under the interior floor slabs should also be mechanically compacted and tested for a minimum of 90% compaction levels. Flooding or jetting techniques as a means of compaction method shall not be allowed. * Pavement/improvements subgrade and basegrade inspections -Prior to the placement of concrete or asphalt for proper moisture and specified compaction levels. VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION l'ERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD 8. Foundations and Interior Floor Slabs PAGE 12 OCTOBER 1, 2003 The following preliminary recommendations are consistent with very low expansive (expansion index less than 21) sandy (SP/SM) foundation bearing soils. Final foundation and slab design will depend on expansion characteristics of finish grade soils and the actual fill differential thickness underneath the proposed buildings. All recommendations should be confirmed and/or revised as necessary in the rough grading compaction report based on-site as-graded geotechnical conditions and actual testing of the foundation bearing soils. Individual building sites may require specific foundation/slab design and may be anticipated. Additional specific recommendations may also be necessary and should be given at the time of the final plan review phase when detailed grading and structural/architectural drawings are available: 1. All building and retaining wall foundations planned on or near the top of descending slopes should be adequately deepened to provide a minimum horizontal distance of 7 feet or one-third of the slope height, whichever is greater (need not exceed 40 feet maximum) between the bottom outside edge of the footing and face of slope. Actual construction details should be provided by the project structural engineer. 2. Continuous strip and perimeter wall foundations should be sized at least 15 inches wide and 18 inches deep for single and two-story structures. Spread pad footings should be at least 30 inches square and 12 inches deep. Footing depths are measured from the lowest adjacent ground surface, not including the sand/gravel beneath floor slabs. Exterior continuous footings should enclose the entire building perimeter. • 3. Continuous interior and exterior foundations should be reinforced by at least four #4 reinforcing bars. Place a minimum of 2-#4 bars 3 inches above the bottom of the footing and a minimum of 2-#4 bars 3 inches below the top of the footing. Reinforcement details for spread pad footings should be provided by the project architect/structural engineer. • 4. All interior slabs should be a minimum of 4 inches in thickness, reinforced with #3 reinforcing bars spaced 16 inches on center each way, placed mid-height in the slab. Slabs should be underlain by 4 inches of clean sand (SE 30 or greater) which is provided with a 6-mil plastic moisture barrier placed mid-height in the sand. In the case of good quality sandy subgrade soils, as approved by the project geotechnical engineer, the 6-mil plastic moisture barrier may be laid directly over the slab subgrade and covered with a minimum of 2 inches of clean sand (SE 30 or greater). VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-034"3 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD PAGE 13 OCTOBER 1, 2003 5. Provide "softcut" contraction/control joints consisting of sawcuts spaced. 10 feet on center maximum each way for all interior slabs. Cut as soon as the slab will support the weight of the saw, and operate without disturbing the final finish which is normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. The sawcuts should be a minimum of 1-inch in depth but not to exceed 1 ¼-inches in depth maximum. Anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. 6. Provide re-entrant corner reinforcement for all int~rior slabs. Re-entrant corners will depend on slab geometry and/or interior column locations. The enclosed Plate 16 may be used as a general guideline. 7. Foundation trenches and slab subgrade soils should be inspected and tested for proper moisture and specified compaction levels and approved by the project geotechnical consultant prior to the placement of concrete. C. Exterior Concrete Slabs / Flatworks 1. All exterior slabs (walkways, and patios) should be a minimum of 4 inches in thickness -reinforced with 6x6/10x10 welded wire mesh carefully placed mid- height in the slab. 2. Provide "tool joint" or "softcut" contraction/control joints spaced 10 feet on centers (not to exceed 12 feet maximum) each way. Tool or cut as soon as the slab will support weight, and can be operated without disturbing the final finish which is normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. Tool or softcuts should be a minimum of 1-inch but should not exceed 1 ¼-inches deep maximum. In the case of softcut joints, anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. 3. All exterior slab designs should be confirmed in the final as-graded compaction report. 4. Subgrade soils should be tested for proper moisture and specified compaction levels and approved by the project geotechnical consultant prior to the placement of concrete. VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD D. Soil Design Parameters PAGE 14 OCTOBER 1, 2003 The following preliminary soil design parameters are based on the tested representative samples of on-site earth deposits. All parameters should be re- evaluated when the characteristics of the final as-graded soils have been sp.ecifically determined: * Design wet density of soil = 124.3 pcf. * Design angle of internal friction of soil= 31 degrees. * Design active soil pressure for retaining structures = 40 pcf (EFP), level backfill, cantilever, unrestrained walls. • * Design active soil pressure for retaining structures = 62 pcf (EFP), 2: 1 sloping backfill surface, cantilever, unrestrained walls. * Design at-rest soil pressure for retaining structures = 60 pcf (EFP), non- yielding, restrained walls. * Design passive soil pressure for retaining structures = 388 pcf (EFP), level surface at the toe. * Design passive soil pressure for retaining structures = 156 pcf (EFP), 2:1 sloping down condition at the toe. * Design coefficient of friction for concrete on soils = 0.38. * Net allowable foundation pressure for on-site compacted fills (minimum 15 inches wide by 18 inches deep footings) = 2000 psf. * Allowable lateral bearing pressure (all structures except retaining walls) for on- site compacted fill = 150 psf/ft. Notes: * Use a minimum safety factor of 1.5 for wall over-turni!7g and sliding stability. However, because large movements must take place before maximum passive resistance can be developed, a safety factor of 2 may be considered for sliding stability where sensitive structures and improvements are planned near or on top of retaining walls. • * When combining passive pressure and frictional resistance the passive component should be reduced by one-third. * The net allowable foundation pressure provided herein was determined for footings having a minimum width of 15 inches and depth of 18 inches. The indicated values may be increased by 20% for each additional foot of depth and 20% for each additional foot of width to a maximum of 4500 psf, if needed. The allowable foundation pressure provided herein also applies to dead plus live loads and may be increased by one-third for wind and seismic loading. VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD PAGE 15 OCTOBER 1, 2003 * The allowable lateral bearing earth pressures may be increased by the amount of the designated value for each additional foot of depth Jo a maximum of 1500 pounds per square foot. * Construction plans, details and profile for the modular (sequential) retaining walls incorporated into the northern slope construction, should be reviewed and approved by the project geotechnical consultant. Additional recommendations should be given at that time if necessary. E. Asphalt and PCC Pavement Design Specific pavement designs can best be provided at the completion of rough grading based on R-value tests of the actual finish subgrade soils; however, the following structural sections may be considered for cost estimating purposes only (not for construction): 1. A minimum section of 3 inches asphalt on 6 inches Caltrans Class 2 aggregate base may be considered for on-site asphalt paving surfaces. Actual design will also depend on the design Tl and approval of the City of Carlsbad. Base materials should be compacted to a minimum of 95% of the corresponding maximum dry density (ASTM D-1557). Subgrade soils beneath the asphalt paving surfaces should also be compacted to a minimum of 95% of the corresponding maximum dry density within the upper 12 inches. 2. Residential PCC driveways and parking supported on non-expansive to very low expansive ( expansion index of less than 21) granular subgrade soils should be a minimum of 5 inches in thickness, reinforced with #3 reinforcing bars at 18 inches on centers each way, placed mid-height in the slab. Subgrade soils beneath the PCC driveways and parking should be compacted to a minimum of 90% of the corresponding maximum dry density. • Provide "tool joint" or "softcut" contraction/control joints spaced 1 0 feet on center (not to exceed 15 feet maximum) each way. Tool or cut as soon as the slab will support weight, and can be operated without disturbing the final finish which is normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. Tool or softcuts should be a minimum of 1-inch but should not exceed 1 ¼-inches deep maximum. In case of softcut joints, anti- ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD PAGE 16 OCTOBER 1, 2003 3. Subgrade and basegrade soils should be tested for proper moisture and the . specified compaction levels and approved .by the project geotechnical consultant prior to the placement of the base or asphalt/PCC finish surface. 4. Base section and subgrade preparations per structural section design, will be required for all surfaces subject to traffic including roadways, travelways, drive lanes, driveway approaches and ribbon (cross) gutters. Driveway approaches within the public right-of-way should have 12 inches subgrade compacted to a minimum of 95% compaction levels, and provided with a 95% compacted Class 2 base section per the structural section design. Base section may not be required under curb and gutters, and sidewalks in the case of non-expansive subgrade soils (expansion index less than 21). Appropriate recommendations should be given in the final as-graded compaction report. F. General Recommendations 1. The minimum foundation design and steel reinforcement provided herein are based on soil characteristics and are not intended to be in lieu of reinforcement necessary for structural considerations. All recommendations should be further evaluated in the site specific study for each individual lot and confirmed by the project architect/structural engineer. 2. Adequate staking and grading control is a critical factor in properly completing the recommended remedial and site grading operations. Grading control and staking should be provided by the project grading contractor, or surveyor/civil engineer, and is beyond the geotechnical engineering services. Inadequate staking and/or lack of grading control may result in unnecessary additional grading which will increase construction costs. 3. Footings located on or adjacent to the top of slopes should be extended to a sufficient depth to provide a minimum horizontal distance of 7 feet or one-third of the slope height, whichever is greater (need not exceed 40 feet maximum) between the bottom edge of the footing and face of slope. This requirement applies to all improvements and structures induding fences, posts, pools, spas, etc. Concrete and AC improvements should be provided with a thickened edge to satisfy this requirement. 4. Expansive clayey soils should not be used for backfilling of any retaining structure. All retaining walls should be provided with a 1: 1 wedge of granular, compacted backfill measured from the base of the wall footing to the finished surface. VINJE & MIDDLETQN ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD PAGE 17 OCTOBER 1, 2003 5. All underground utility and plumbing trenches should be compacted to a minimum of 90% of the maximum dry density of the soil unless otherwise specified. Care should be taken not to crush the utilities or pipes during the compaction of the soil. Non-expansive, granular backfill soils should be used. 6. Site drainage over the finished pad surfaces should flow away from structures onto the street in a positive manner. Care should be taken during the construction, improvements, and fine grading phases not to disrupt the designed drainage patterns. Roof lines of the buildings should be provided with roof gutters: Roof water should be collected and directed away from the buildings and structures to a suitable location. Considerations should be given to adequately damp-proof/waterproof the basement walls/foundations and provide the planter areas adjacent to the foundations with an impermeable liner and a subdrainage system. 7. Final plans should reflect preliminary recommendations given in this report. Final foundations and grading plans may also be reviewed by the project geotechnical consultant for conformance with the requirements of the geotechnical investigation report outlined herein. More specific recommendations may be necessary and should be given when final grading and architectural/structural drawings are available. 8. All foundation trenches should be inspected to ensure adequate footing embedment and confirm competent bearing soils. Foundation and slab reinforcements should also be inspected and approved by the project geotechnical consultant. 9. The amount of shrinkage and related cracks that occurs in the concrete slab- on-grades, flatworks and driveways depend on many factors the most important of which is the amount of water in the concrete mix. The purpose of the slab reinforcement is to keep normal concrete shrinkage cracks closed tightly. The amount of concrete shrinkage can be minimized by reducing the amount of water in the mix. To keep shrinkage to a minimum the following should be considered: * Use the stiffest mix that can be handled and consolidated satisfactorily. * Use the largest maximum size of aggregate that is practical. For example, concrete made with %-inch maximum size aggregate usually requires about 40 lbs. more (nearly 5 gal.) water per cubic yard than concrete with 1-inch aggregate. • VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I PLAN REVIEW GEOTECHNICAL UPDATE REPORT HIGHLAND DRIVE, CARLSBAD * Cure the concrete as long as practical. PAGE 18 OCTOBER 1, 2003 The amount of slab reinforcement provided for conventional slab-on-grade construction considers that good quality concrete materials, proportioning, craftsmanship, and control tests where appropriate and applicable are provided. 10. A preconstruction meeting between representatives of this office, the property owner or planner, the grading contractor/builder, and the city inspector is recommended in order to discuss grading/construction details associated with site development. VII. LIMITATIONS The conclusions and recommendations provided herein have been based on available data obtained from pertinent reports and plans, as well as our experience with the soils and Formational materials located in the general area. The materials encountered on the project site and utilized in our laboratory testing are believed representative of the total area; however, earth materials may vary in characteristics between excavations. Of necessity we must assume a certain degree of continuity between exploratory excavations and/or natural exposures. It is necessary, therefore, that all observations, conclusions, and recommendations are verified during the grading operation. In the event discrepancies are noted, we should be contacted immediately so that an inspection can be made and additional recommendations issued if required. The recommendations made in this report are applicable to the site at the. time this report was prepared. It is the responsibility of the owner/developer to ensure that these recommendations are carried out in the field. It is almost impossible to predict with certainty the future performan·ce of a property. The future behavior of .the site is also dependent on numerous unpredictable variables, such as earthquakes, rainfall, and on-site drainage patterns. The firm of VINJE & MIDDLETON ENGINEERING, INC., shall not be held responsible for changes to the physical conditions of the property such as addition of fill soils, added cut slopes, or changing drainage patterns which occur without our inspection or control. The property owner(s) should be aware that the development of cracks in all concrete surfaces such as floor slabs and exterior stucco are associated with normal concrete shrinkage during the curing process. These features depend chiefly upon the condition of concrete and weather conditions at the time of construction and do not reflect detrimental ground movement. Hairline stucco cracks will often develop at window/door corners, and VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, facondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I I I I I DATE OBSERVED: LOGGED BY: R.G. -::: I-Q w ~ w I.. 2 .... :r: !:!: ... (I) 0. en ... Q 0 w 0 mw "" C:..J -::>a. (I) t--: ~ (I)-_-c 0 ocn w < ...J z 0 ..J m ::, .... 80 CJ - - - - 85 ~ . . -. 90· . . -. 95-. . . . 100· . . . 105. . . . 110- - 115 - . 120- JOB NO.: GN-l w ...J a. :E < (I) !.:: ...J ::, m. 11/7 /87 METHOD OF DRILLING: 30 inch bucket auger 4113 lbs to 25', 2981 lbs to 41', 2168 lbs to 70' GROUND ELEVATION: -155± LOCATION: See Geotechnical Map .... >-~ w~ c:o Qc.. a:.,_ .... :::,_ w t--o>-Cl)W _.., < ... 0% ..JC/) ::::o. a.z zW 0 -c BORING NO. B-1 (CONTINUED) DESCRIPTION White fine SANDSTONE, slightly moist, ·sOIL TEST dense contacts: horizontal, undulatory, gradational @ 83' clayey siltstone, 7" thick Total ·nepth 85' No water , LOG OF BORING !FIGURE: B-J PLATE 8 : DATE OBSERVED: __ .... I 0""-(2=,.3...,_lw.8 .. 7 ____ METHOD OF OR ILL ING: Hatachi Trac~ka:.....:H~o~e~------,-- OGGED BY: R.G. ;:: --I-0 .... C 1/J UJ I-0 UJ _, .u < 0 alw a. LI. 0 I.. c:: -I :I --::> C. < :I: I.. C') .... :::E CD I-C') ~ !!'.!< ~ a. C') 0 ea, w < -l C -l -' -::> m ::> m -0 - -- -- - - 10-. -- 15-. - I .OGGE0 BY: • RIG I -- I . . . &- . I -. 1~ [> --< . t> "'.: > '«.S > 0- - - JOB NO.: GN-1 I GROUND ELEVATION: 150+ LOCATION: See Geotechnical Map .... w! ct I- ~% c,W -1-oz :EC (.) >-u:-a:u Cc. -TEST PIT NO. ___ 3 ___ w u>-<t: -' en a.z -w DESCRIPTION ::c Fill: Red brown medium SAND, moist, "-.. loose "'--1-,,,.c_o-:n...;t_a...;c~t...;:_..;.N..:6;..;0;;.;Ee-',:.....6:..0:..0..:N~...,,,.--------~---4 Bedrock: Linda Vista Formation; Red. . brown coarse SANDSTONE, slightly moist, dense bedding: horizontal below 6' grades to light brown medium sandstone NOTE: Fill exposed in northern half of test pit to bottom @ 12' concrete pieces in fill Total Depth 14' No water SOIL TEST GROUND ELEV I. TION: 1!?0+ LOCATION: See Geo technical Ma:e TEST PIT NO. 4 ~ Fill: Red brown silty medium SAND, --slightly moist, loose Bedrock: Linda Vista Formation; Red brown ~oarse SANDSTONE, slightly· moist, dense NOTE: Fill exposed in western portion of test pit to bottom Fill/bedrock contact: N35W, 50°W . contact: horizontal, undulatory Santiago formation; white brown fine to medium SANDSTONE." slightl v moist. dense T~tal Depth 21' No water l LOG OF TEST PIT jFIGURE: TP-2 .. PLATE 11 ~ DATE OBSERVED: LOGGED BY: r r r r r f ' ' ' ' r --t- UJ LIJ I.I. -::: I-Q,. UJ 0 -- . . - '5- ---. 10- --- 1S-· - - ;.;_ 0 I--0 I-< 0 0 I.I. -I.I. a, "' :t "' 0 < ..I ..J Cl u r r r LOGGED BY: ' I I' -- . - ·s- -. - t.0- - - ·- 15- - - Rz!:.i1 Q w w ...I CJUJ A. :I C:::..,1 :::> Q,. < I-:f ID !!? < ~ gen ...I :::> ::) m rx . R.G. I I I JOB NO.: CN-l 10/23/87 METHOD OF DRILLING: Eatai::b;i I:cack Hee GROUND ELEVA TIOH: lSQ+ LOCA 'r 10N: See GectecbDjcal l:fap -,.. u:- LI.I! a:u TEST PIT NO. 9 0 Q,. a: I--::) :::z: uJ ... w u>-SOIL TEST ~ ... <t: oz ...I er, :lO c.z DESCRIPTION -UJ c., =c Fill: Dark brown silty medium SAND, --moist, loose contact: E-W, 60°S Bedrock: Santiago Formation; white brown medium SANDSTONE, slightly moist, dense· crossbedding: horizontal Total Depth 11' No water ·r GROUND ELEVATION: 150+ LOCATION: See GeotechnicaJ Map TEST PIT NO. 10 Dark brown silty medium SAND, Fill: --moist, loose contact: N40W. 75°W Bedrock: Linda Vista Formation; Red brown medium to coarse SANDSTONE, slightly moist·, dense fracture plane: N35W, 78°W Total Depth 11' INo water I LOG OF TEST PIT !FIGURE: TP-5 PLATE 14 I I I I I I I I I APPENDIX A I I I I I I I I I I I I I I I I I I I ·' I I I I I I I I I I forcement lnstallat,On Gui e TENSAR® Geog rids are a proven technique for building steep reinforced slopes without steep prices-for better and more profitable land use in a wide number of applications. This guide covers the recommended steps for instailation of TEN SAR Geogrids in reinforced slopes. Figure 1: A Tensar Reinforced Slope This guide is for illustration and not for design or specification pur- poses. See disclaimer on page 6. I I I I I I I I I I I I I I I I I I f ntroduction The guideline covers: (a) tools required; (b) cutting geogrid strips to the required lengths; (c) site excavation; (d) drainage; (e) placement of uniaxlal geogrids; (f) fill placement and compaction; (g) intermediate reinforcement; (h) protection of the finished slope against erosion; and (i) special instructions for biaxial geogrids. Tools ~ Circular saw. fii:;'J Sawhorses and plywood to construct a work table to cut geog rids. • ~ Steel pipe for unrolling geogrids on work table. ~] Hog ringer with boxes of hog rings-optional. ~ Steel "U" pins for securing geogrid to ground- optiona/. ~ Spray paint (one color for each type of geogrid, if more than one grade is used). Step 1-Cut Geogrid ~ Color code the ends of the geogrid rolls if more •• ,:;:•:. 't:."• •.j• • r • Figure 2: Color Coding Geogrid Rolls t.~,, ~ ,>?), 'A'i:w • ~ -~ , ', ~ ~ ~~,..n-·u,.. ....... ,.,~,. •. ,,...,.,,,.,. Figure 3: Cutting Geogrids 2 than one type of geogrid is specified (FIGURE 2). ~ Cut geogrids to lengths shown on the construc- tion drawings. Never cut the heavy ribs that span the width of the roll. !;Ji An easy way to cut the geog rid is on a work table using a circular saw (FIGURE 3). ~ As each length of material is cut, mark and tag it according to length and type, and stockpile it for later use. ~ You may want to join several precut geog rid strips together side-by-side using hog-rings (FIGURE 4). This step can increase the speed of subsequent geog rid pf acement and is most often used on large projects. Tagging strips or units of joined strips with the elevation and station can also speed construction. . The correct geogrid type and lengths must be used at each lift level according to the project design. Figure 4: Joining Geogrid Strips . Biaxial Uniaxial