Loading...
HomeMy WebLinkAboutCT 77-02; Hosp Grove No. 8; Soils Report; 1979-07-19Project No. 59207A-SIOl SOIL AND GEOLOGICAL INVESTIGATION FOR THE PROPOSED CARLSBAD TRACT NO. CT 77-2 PLANNED UNIT DEVELOPMENT NO. 8 HOSP GROVE CARLSBAD, CALIFORNIA for Broadmoor Homes, Inc. 3911 Sorrento Valley Boulevard Suite B San Diego, California 92121 r 3467 Kbtfz Street San Diego. Callfornla 92110 714-224-2911 Telex 697-841 March 23, 1981 Project No. 592072-FCOl Woodward6lyde Consultants Broadmoor Homes, Inc. 3911 Sorrento Valley Boulevard Suite B San Diego, California 92111 Attention: Mr. James Carter BUTTRESS DESIGN WOODRIDGE UNIT 5, AREA WEST OF MONROE STREET CARLSBAD, CALIFORNIA Gentlemen: In accordance with your request and our verbal recommenda- tions we are presenting design recommendations for the construction of a buttress west of Lots 130 through 140 in the subject subdivision. For our study we have been present& a "Supplemental Grading Plan, Carlsbad Tract 77-2 Unit 5" prepared by Roy L. Klema Engineers, Inc. dated February 1981. The grading plan indicates that the irregular topography within the slide area identified by geologists from our firm, will be graded so as to form a smooth slope with an inclination of approx- imately 2 to 1 (horizontal to vertical). Maximum vertical cuts will be on the order of 20 feet. BACKGROUND INFORMATION Our "Soil and Geological Investigation for the Proposed Carlsbad Tract No. CT 77-2 Planned Unit Development No. 8, Hosp Grove, Carlsbad California" dated July 19, 1979, identi- fied a landslide within the hillside west of Monroe Street in the northwestern part of the site. A test boring placed at the toe of the slope did not encounter any landslide planes. Subsequent geologic investigation identified a slide plane within a cut bank along the west side of an existing dirt road near the toe of the slope. The slide plane was noted at approximate Elevation 97 (MSLD), above the test boring. Because of the difficulty involved and the large number of trees present on the hillside no additional test borings were made. The approximate limits of the landslide are shown on Fig. 1. Consulting Engineers. Geologists and Enwronmenta Scientists Offices in Other Prinooai Cities .’ . Broadmoor Homes, Inc. March 23, 1981 Project No. 592072-FCOl Page 2 Woodward-Clyde Consultants CONCLUSIONS AND RECOMMENDATIONS Qurgeolqgic mapping and field investigations indicate an ancient~landslide~is present within the hillside west of Monroe Street behind Lots 130 through 140 and extending offsite to the north. Our field investigation did not evaluate the depth of the landslide, however, for our analysis we have assumed the slide is deep-seated. The slide plane geometry and soil shear strength parameters assumed are shown on the sketch below. TYPICAL BUTTRESS SECTION (No Scale) 140 - r; : 5 120- E ..- 2 ~~ $ ,100 -. 80 - h Existing Ground Surface Area Graben Neutral Block 0" c (psf) Y-(pcf) 24 0 120 10 0 120 Buttress 33 300 125 We recommend that the landslide area be treated by one of the two methods outlined below: we also recommend that all . . . . Broadmoor Homes, Inc. March 23, 1981 Project No. 592072-FCOl Page 3 Woodward4Xycle Consultants grading within the landslide area be observed by an engi- neering geologist from our firm to evaluate geologic conditions. a) If during grading the slide plane is found to be shallow we recommend that the landslide be com- pletely removed. b) If the slide plane is deep-seated we recommend a drained buttress be constructed within the limits shown on Fig. 1. A typical cross section of the buttress at the maximum section is shown on the attached "Guide Specifications for Typical Buttress." A drain should be installed at the rear of the buttressed slope as indicated. We recommend with either mitigating measure the excavated material be replaced and properly compacted. The stability of construction slopes should be the responsi- bility of the contractor. Grading during the rainy period may cause construction slope failures. If you have an questions, please call us. Very truly yours, WOODWARD-CLYDE CONSULTANTS Richard P. While R.E. 21992 P.PW/MRR/mam Attachments (2) GUIDE SPECIFICATIONS FOR TYPICAL BUTTRESS I. DESCRIPTION Buttresses consisting of compacted, granular fill shall be installed as shown on the plans in accordance with these specifications, unless otherwise specified by the engineer. Typical cross sections are shown on the sketch. II. CONSTRUCTION The buttresses shall be composed of compacted, granular material as described in the report recommendations. Chimney drains consisting of filter gravel and perforated pipe shall be installed as shown on the sketch. III. PERFORATED PIPE AND FILTER GRAVEL Collector pipe shall be 6-inch diameter, perforated, thick walled ABS or PVC pipe sloped to drain to outlet pipe. Outlet pipe from buttress shall be nonperforated and should slope at 1 percent minimum to drain to a convenient outlet. Filter material for use in backfilling chimneys and around and over drain pipe shall consist of clean, coarse sand and gravel or crushed stone conforming to the following grading requirements. Sieve Size Percentage Passing Sieve 1" 100 3/4" 90 - 100 3/8" 40 - 100 4 25 - 40 8 18 - 33 30 5- 15 50 o- 7 200 o- 3 This material generally conforms with Class II permeable material in accordance with Section 68-l-025 or combined aggregate. section 90-3.04 of the Standard Specifications of the State of California, Department of Transportation. IV. LAYING Trenches for drains shall be excavated to a minimum width equal to the outside diameter of the pipe plus 1 foot and to the depth shown on the plans or as directed by the engineer. The bottom of the trench shall then be covered full width by 4 inches of filter material and the drain pipe shall be laid with the perforations at the bottom and sections shall be joined with couplers. The pipe shall be laid on a minimum slope of 0.2 percent. After the pipe has been placed, the trench shall be back- filled with filter material to the elevation shown on the plans, or as directed by the engineer. . . Filter gravel Perforated Pipe Finish 5' Grade - t LATTICE LAYOUT OF BUTTRESS DRAINS 24 " (No Scale) Minimum ,;I ,eollector Drain Pipe - --zxT- -- - 2 4 " Yinimum encasement Seepage collector pipe Minimum 6" diameter Bottom of Buttress Excavation I r r r r r r r r r r~ -. -. - -. - - 3467 KurlzStreet San Diego, California 92110 714-224-2911 Telex 697.641 Woodward4lyde Consultants July 19, 1979 Project No. 59207A-SIOl Broadmoor Homes, Inc. 3911 Sorrento Valley Boulevard Suite B San Diego, California 92121 Attention: Mr. James L. Henry SOIL AND GEOLOGICAL INVESTIGATION FOR THE PROPOSED CARLSBAD TRACT NO. CT 77-2 PLANNED UNIT DEVELOPMENT NO. 8 HOSP GROVE CARLSBAD, CALIFORNIA Gentlemen: F7e are pleased to present the results of our soil and geolog- ical investigation for the subject project. The accompanying report presents our conclusions and recom- mendations pertaining to the subject project, as well as the results of field explorations and laboratory tests. Our geologist assigned to this project is Mr. S. Thomas Freeman. If you have any questions or if we can be of further service, plase call or write at your earliest con- venience. Very truly yours, WOODWARD-CLYDE CONSULTANTS Braven R. Smillie C.E.G. 207 BRS/RPW/STF/vn Richard P. While R.E. 21992 Attachment (4) Consultmg Engineers. Geologists and Enwonmenral Scienttsts OfWes in Other Princiml Cities Project No. 59207A-SIOl r r r r - r TABLE OF CONTENTS Woodward-Clyde Consultants Page 1 2 3 4 9 20 22 SCOPE AND PURPOSE OF INVESTIGATION DESCRIPTION OF PROJECT FIELD AND LABORATORY INVESTIGATIONS SITE, SOIL, AND GEOLOGIC CONDITIONS DISCUSSION, CONCLUSIONS, AND RECOMMENDATIONS GENERAL REFERENCES FIGURE I - SITE PLAN AND GEOLOGIC MAP FIGURES 2 THROUGH 11 - LOGS OF TEST TRENCHES APPENDIX A - FIELD INVESTIGATION 23 FIGURE A-i - KEY TO LOGS FIGURES A-2 THROUGH A-4 - LOGS OF TEST BORINGS APPENDIX B - LABORATORY TESTS FIGURE B-l - GRAIN SIZE DISTRIBUTION CURVES FIGURE B-2 - FILL SUITABILITY TESTS APPENDIX C - SPECIFICATIONS FOR CONTROLLED FILL APPENDIX D - DRAINS IN DRAWS SPECIFICATIONS ATTACHMENT I - WOODWARD-CLYDE & ASSOCIATES' APRIL 13, 1968 LOGS - r r r r r - Project No. 59207A-SIOl Woodward-Clyde Consultants SOIL AND GEOLOGICAL INVESTIGATION FOR THE PROPOSED CARLSBAD TRACT NO. CT 77-2 PLANNED UNIT DEVELOPMENT NO. 8 HOSP GROVE CARLSBAD, CALIFORNIA SCOPE AND PURPOSE OF INVESTIGATION This report presents the results of our soil and geological investigation at the site of a proposed residen- tial development. The 43.9-acre site is located in Carlsbad, Calif- ornia. It is bounded on the west by Monroe Street, and on the south by Buena Woods Unit No. 1 subdivision. The purpose of the investigation is to provide conclusions and recommendations regarding subsurface soil and geologic conditions, g~radinq, stability of proposed cut and fill slopes, disposition and treatment of potentially expansive and compressible soils, availability of select fill material, excavation characteristics, suitable types and depths of foundations, and allowable soil bearing pres- sures. In addition, we are presenting conclusions regarding geologic hazards at the site. This investigation updated previous work performed for this site in conjunction with the study of a larqer area. 1 Project No. 59207A-SIOl r r r r T T T T T -r T T T WoodPvard4Xyde Consultants DESCRIPTION OF PROJECT To aid in our investigation, we have discussed the project with Mr. James L. Henry and Mr. Dennis Shields, of Broadmoor Homes, Inc. We have been provided with the plan entitled "Tentative Map, Carlsbad Tract No. 77-2, Planned Unit Dev. No. 8," prepared by Roy L. Klema Engineering, dated January 27, 1977. We understand that-the proposed project will con- sist of grading the site into single and split-level build- ing pads for the construction of multi-family, residential dwelling units, along with access roads, parking areas, bike trails and hiking paths, and park and open-space areas. It is our understanding that the proposed con- struction will be limited to one and two-story, wood-frame structures, supported on continuous footings, having slab- on-grade floors. The available tentative map indicates that cut slopes are proposed having maximum heights of 20 feet and maximum slope inclinations of l-112 to 1 (horizontal to vertical): fill slopes are proposed having maximum heights of 15 feet and maximum slope inclinations of 2 to 1. Exca- vation depths up to 15 feet and depth of fill up to 25 feet are indicated. 2 Project No. 59207A-SIOl Woodward-Clyde Consultants FIELD AND LABORATORY INVESTIGATIONS Previous work for this area was done between November 11, 1967 and January 28, 1968, by Woodward-Clyde & Associates. Sixteen 6-inch diameter, continuous-flight auger borings were drilled on the site. The previous boring logs and laboratory test results are detailed in Woodward- Clyde & Associates' report dated April 13, 1968. Data pertinent to the subject site are included as Attachment I. Current field work for the Hosp Grove development was conducted by a project geologist from our firm between July 5 and 13, 1979. This work included making;a visual geologic reconnaissance of the existing surface conditions, excavating ten 18-inch wide backhoe trenches, and drilling two 36-inch diameter bucket auger borings. The test trenches were advanced to depths of 5 to 14 feet, and the bucket auger holes from 32 to 57 feet. The test trenches and borings were made at the approximate locations shown on the Site Plan and Geologic Map, Fig. 1. A Key to Logs is pre- sented in Appendix A as Fig. A-l. Loqs of trench excava- tions are given on Figs. 2 through 11. Simplified logs of test borings are presented on Figs. A-2 through A-4. The descriptions on the logs of test borings are based on field logs, sample inspection, and laboratory test results. Samples recovered from the trenches and borings were transported to our laboratory for inspection and testing. Results of the laboratory tests are shown in Appendix B as Figs. B-l and B-2. 3 i - Project NO. 59207A-SIOl Woodward-Clyde Consultants SITE, SOIL, AND GEOLOGIC CONDITIONS Site Conditions The site is located in a thick grove of eucalyptus trees, ranging from saplings to 18 inches in size. The site topography is characterised by southwest to westward-sloping ridges and valleys that drain into a northwest-trending canyon at the southwestern to western edge of the site. Natural slopes are generally. less than 4 to 1 (horizontal to vertical); however, in the southwestern portion of the site and in the northeastern portion of the central recreational area, the slopes may be as steep as 2 to 1 or even vertical. Elevations range from about 40 feet (MSL Datum) at the northwest part of the site in the main drainage, to a high of 212 feet at the western boundary (MSL Datum). Severe erosion along the northwest-trending drain- age has resulted in a steep-sided arroyo, which is 18 to 20 feet deep. The erosion is primarily due to the concentrated discharge from a storm drain into the natural drainage located about 4,800 feet northwest of the present end of Monroe Street. Trash and debris were observed in the bottom of the arroyo and has been covered by large blocks of soil that have caved into the arroyo. An existing sewer line parallels the proposed extension of Monroe Street. Elan-made fill has been placed along the southeastern approximately 6,600 feet of the proposed Monroe Street extension. The 4 . r - r r’ - Project No. 59207A-SI01 Woodward-Clyde Consultants fill was probably placed in conjunction with the construc- tion of the existing sewer line and storm drain. An access road is present along the alignment of the sewer line, and extends eastward along the northern margin of the site. No other man-made structures exist on the site except for end-dumped piles of trash and debris and a dozer trail, which was constructed along the west side of Unit No. 5 for this study. Geologic Setting The Hosp Grove site is underlain by Quaternary age alluvial and formational units and a Tertiary age formation. Exposures are limited to local areas in stream drainages and those uncovered in test pits, borings, and cuts made for trails as part of this study. The majority of the site is covered by a thin veneer (0 to 5 feet) of topsoil and colluvium, which is not a mappable unit. These soils are usually soft or loose, dark gray to brown, silty sands, sandy clays, and clayey sands, which are rich in organic and plant matter (e.g., roots). In some areas, especially near the toe of some slopes, the colluvium may reach a thickness of 10 feet. Quaternary alluvial deposits (Qal) fill the north- west-trending valley and extend into the southeast-draining valleys. These alluvial deposits are generally derived from the surrounding formational units and consist of soft and 5 Project No. 59207A-SIOl WoodwardGlyde Consultants - loose to dense, dark gray to reddish brown, silty sands, sandy silts, clayey sands to sandy clays, silty clays, and minor amounts of gravel. The alluvium ranges in depth from a few feet up to at least 20 feet. A Quaternary terrace deposit (Qt) of probable Pleistocene age locally overlies the older formational unit at the lower elevations along the main canyon at the south- western to western boundary of the site. These deposits consist of interbeds of silty sands, and sandy silts, and occasional clay layers and gravel beds; they are limited in extent. The unit is commonly crossbedded with channel fill structures and thin laminations. Two previously mapped formational units are exposed on the site: the Pleistocene age Lindavista Formation (Qln) and an Eocene sandstone formation of the La Jolla Group that has also been mapped by Wilson (1972) as the Santiago Forma- tion (Ts). The Pleistocene age Lindavista Formation lies beneath the eastern portion of the site, and is best exposed in the amphitheater of "badland" topography found in the central recreational area. The formation is composed pri- marily of silty sand, clayey sands, and sandy clays. It is massive and lacks any well-defined bedding, except for an occasional pebble layer. Iron oxide gives this formation its reddish brown color, and acts somewhat as a cementing r r r - I- I- T r T T T T T T I T T Project No. 59207A-SIOl Woodward-Clyde Consultants agent. The Lindavista formation has a cemented hardpan that will be difficult to rip except by heavy equipment. The unconformable contact between the Lindavista formation and the underlying Tertiary formation is irregular and varies from nearly horizontal to a gentle southward dip. The Tertiary sandstone formation is also best exposed in the amphitheater of "badland" topography in the central recreational area; it is also exposed locally in the arroyo walls of the northwest-trending valley. The forma- tion is primarily a massive white to light yellowish gray, silty, clayey, fine to coarse sandstone and sandy claystone. Locally, olive gray claystone interbeds occur. The forma- tion erodes easily, as evidenced by the development of "badland" topography. Bedding attitudes within this unit are noted to vary considerably. In Test Boring 1, the beds have a dip 17 degrees to the east. Wilson's (1972) mapping in the area indicates bedding attitudes within the Santiago formation have dips that range from horizontal to 13 deqrees toward the north, west, and south. The groundwater beneath the site is largely con- fined to the alluvial filled valleys. Depth of groundwater, as encountered in the test borings on the site, varies from 27 to 54 feet below the surface at the time of boring. Water was also noted to be flowing from the storm drain into the deep arroyo; iteventually disappeared into the subsurface. Project No. 59207A-SIOl Woodward-Clyde Consultants r- -- -,. -. -. Potential Geologic Hazards A fault has been identified crossing the north- western corner of the site. As exposed in the northwest- trending arroyo on Lots 119 and 120, the fault displaces the base of the Santiago white sandstone more than LO feet. As exposed in the arroyo and cut road above, the capping Pleis- tocene terrace deposit has also been offset by a few inches. A significant amount of strike-slip component of displace- ment is indicated by oblique slickenside stria and discordi- nances in the vertical displacement of various stratigraphic horizons. The total inferred length of this fault, based on this study and the work of others (Hannan in Ross and Dowlen, - 1975), is about 3/4 mile. The fault has a similar t,rend to other faults mapped in the Carlsbad-Oceanside area (Hannan in Ross and Dowlen, 1975). - During the review of aerial photographs for the site, a lineament was observed passing through Lots 47 through 52 having a trend similar to the previously mapped fault. Test Trench 1 was placed across the most prominent break in slope along the lineament. No evidence of faulting was uncovered in the Lindavista formation and underlying Tertiary sandstone exposed in the test trench. During the geologic reconnaissance in the area of Lots 115 through 120, what appeared to be sliding of the surface soils was identified. This sliding was further - - 8 - Project No. 59207A-SIOl WoodwardXlyde Consultants i r studied by constructing an access trail and drilling large- diameter borings. The sliding has been subsequently identi- fied as mass slumping (a landslide) within the terrace deposits. The plane upon which the failure has occurred is exposed in a cut slope of the access trail, and consists of a 6-inch to l-foot thick, soft, moist, gray, clay layer. Above this slide plane, several thin clay beds and sand beds exhibit irregular dips, both'into and out of the slope, indicating the slide mass is highly disturbed at this loca- tion. The slide plane appears to cross the location of the lots at the approximate elevations of 85 to 95 feet (MSL Datum). Below these elevations, no evidence of any deeper slide planes was found in Test Boring 2. DISCUSSION, CONCLUSIONS, AND RECOMMENDATIONS The discussion, conclusions, and recommendations presented in this report are-based on the results of our recent f~ield studies, previous field and laboratory studies, experience, and professional judgment. Potential Geologic Hazards Faulting and Ground Breakage - The fault identi- fied in the natural erosional exposure (see Fig. 1) is shown to offset a Pleistocene age terrace material, which has not been assigned a relative age in the Carlsbad area: however, the field investigation does indicate that the fault does -. - 9 Project No. 59207A-SIOl Woodward-Clyde Consultants i r - r r - I- T - T - I T 1 1 1 - not displace the residual soil/colluvium present at the fault exposure. Previous dating of residual soil in the Carlsbad area suggests that these materials are on the order of several thousands of years old. Based on previous studies of faults in the Carls- bad area and considering the fault conditions at the site, it is our opinion that the fault should not be a constraint to development of the site. ,- The Carlsbad area has historically had a rela- tively low level of seismic activity when compared with other areas of southern California; however, ground shaking in the area can be expected from earthquakes generated on faults outside of the area. The fault closest to the site that has historically generated earthquakes greater than magnitude 4 is the Elsinore fault, located about 23 miles east of the site. The major faulting closest to the site is within the offshore zone of deformation located about 4 miles offshore from Carlsbad. Ground shaking during earth- quakes generated from these distant faults is not antici- pated to have any greater effect on this site than any other site in the Carlsbad area. Liquefaction - Soil and groundwater conditions within the site indicate that the potential for liquefaction is very low. The alluvial soils on the site are the most susceptible to liquefaction, consequently the recommendation 10 Project No. 59207A-SIOl , .I .,-’ , -7 7 _-_ - Woodward-Clyde Consultants in the "Grading" section of this report to excavate and recompact these soils serves to reduce the liquefaction potential. Landslides - A landslide area has been identified on the site and is shown on the Site Plan and Geology Map, Fig. 1. The location of the landslide is based on the field exploration and inspection of the existing natural slope. The landslide area appears as several hummocky mounds and has surface relief that suggests it is shallow. Any grading in the area of the landslide could lead to a potentially unstable condition. Such a condition would require the construction of a buttress or other stabil- izing measure, depending on the extent and location of excavation. In this regard, existing topographic maps may be in error; that is, the landslide may be more prominent in the field than that indicated by maps. It is our understand- ing that a new topographic map will be prepared. Analysis of the landslide should not be done before this is available. We recommend that any proposed excavation in the landslide area be analyzed after new topographic maps and grading plans are developed. Groundwater - Based on our studies and experience in the area, we do not believe a shallow groundwater table exists on the site; however, seasonal groundwater in the alluvial areas and perched water in the formational materials -- 11 Project No. 59207A-SIOl Woodward-Clyde Consultants T T - T T T i 1 1 1 1 1 are expected and may be encountered during grading. It has been our experience that the probability of water seepage occurring in cut slopes in the Tertiary age formations is generally low; however, to help evaluate the potential for seepage, we recommend that all cut slopes be inspected by an engineering geologist during grading. In the event that seepage is encountered during grading or appears likely following construction, recommendations for the control of seepage in cut slopes can be made at that time. We recommend that positive measures be taken to properly finish grade each lot after the residential struc- tures and other improvements are in place, so that drainage waters from the lots and adjacent properties are directed off the lots and away from foundations, floor slabs, and slope tops. Even with these provisions, experience has shown that a shallow or near-surface groundwater condition can and may develop in areas'where no groundwater existed prior to site development; this is particularly true in residential developments where a substantial increase in surface water infiltration results from landscape irrigation or heavy rainfall. Soil Characteristics The following is a discussion of the anticipated soil characteristics at the site. 12 Project No. 59207A-SIOl Woodward-Clyde Consultants -~Existing.Fill -..Fill,.to anunknown depth, is present along a portion of the canyon bottom in the southwest corner of the, site. Records indi- cate that the fill was placed in conjunction with installation of the existing sewer' line. Existing compacted fill also exists in the tennis court area. ~Compaction records are on file for these fills, and will be issued with the final report of grading.~ Compressible Soils, such as porous alluvium, slopewash, and topsoils, range in depth from 0 to approximately 7 feet. The average depth of com- pressible soil in the main drainage bottom is estimated, to be on'.the~~order of 4 feet; however, depths may extend to 10 feet. Block falls of material are present within the arroyo, and are considered compressible. Volumes of this material will vary, depending on the height of the arroyo where the falls occurred. Potential Expansive Soils - Residual clays typic- ally occur along daylight lines: that is, areas of shallow cuts and fills. Slightly to moderately expansive soils are anticipated to occur locally at or near finish grade elevations in deeper cut areas. Finish Grade Soils are anticipated to range from nonexpansive to moderately expansive (swells from 0 to 6 percent under a surcharge load of 160 psf), and will be generated from the formational mate- rials on the site. Slopes For the proposed cut and fill slopes, we have performed stability analyses by the Janbu method. The results of our analyses indicate that the slopes have calcu- lated factors of safety in excess of 1.5 for static condi- tions. Stability analyses require the use of parameters selected from a range of possible values: thus, there is a 13 T T T I T T T I 7 Project No. 59207A-SIOl > , Woodward-Clyde Consultants finite possibility that slopes having calculated factors of safety, as indicated above, could become unstable. It is our opinion that the probability of slopes becoming unstable is low, and it isour professional judgment that the slopes can be constructed as proposed. The landslide area appears stable in its natural state; however, proposed cutting of the slope near the toe of the slide area will decrease this natural stability. Stability analyses will be performed, and design recommenda- tions for stabilizing the slide mass will be presented in an addendum report when grading plans indicating the actual topography of the slopes are available. Grading The following are our recommendations for ground preparation and earthwork and are presented in an order corresponding to the sequence of general grading operations. Plan Review - Grading plans should be reviewed by our firm prior to finalization to verify that they express the intent of our recommendations. Grading Specifications - All grading should be done in accordance with the attached Specifications for Controlled Fill (Appendix C). All grading should be ob- served by and compacted fills tested by our firm. Preconstruction Conference - A preconstruction conference should be held at the site with the owner, 14 Project No. 59207A-SIOl Woodward-Clyde Consultants r r c - developer,, design engineer,, grading contractor, and soil engineer in attendance. Special handling of~soils or antici- pated grading difficulties, can be discussed at that time. Clearing and Grubbing - All tree stumps and root systems should be completely removed from the ground and disposed of off the site. The resulting cavities left by stump and root removal should be filled with properly com- pacted soils prior to the placement of new fill or the construction of buildings. Compressible Soils - All potentially compressible soils, such as porous alluvium and block fall material in the canyon bottoms, slopeswash soils, and topsoils, should be excavated and compacted prior to the placement of new fill or the construction of buildings. The approximate limits of alluvium are indicated on Fig. 1. The maximum depths are anticipated to be on the order of 10 feet; depths are expected to vary and should be verified by the soil engineer or his representative during grading operations. Canyon Subdrains - We recommend that canyon sub- drains be installed in the major north-trending canyon in accordance with the attached Subdrains in Draws Specifica- tions (Appendix D). Expansive Soils - Moderately to highly expansive soils that occur within 2 feet of finish grade elevation in areas of shallow cut and fill or in deeper cut areas should - 15 r Project No. 59207A-SIOl Woodward-Clyde Consultants be excavated and replaced over the entire pad area with finish grade soils that have a potential expansion of no greater than 6 percent, as previously defined. Similarly, the upper 2 feet of fill on all fill lots should consist of finish grade soils. Finish grade soils should be placed and properly compacted at moisture contents between 3 to 4 percent over the optimum moisture content. This moisture should be maintained until concrete has been placed. Depend- ing on construction schedules, periodic wetting of pads may be required; if pads dry out* presaturation will be required. Moisture content tests should be taken (the day before placement of concrete) to verify the proper moisture content. Moderately to highly expansive soils may be placed and properly compacted in the deeper portions of fills. Foundations We recommend that foundations for one and two- story, multi-family, residential buildings supported on continuous footings, and having slab-on-grade floors can be designed for an allowable bearing pressure of 2,000 psf (dead plus live loads) at a depth of 12 inches below rough or compacted lot grade. Foundations should have a minimum width of 12 inches. The bearing pressure can be increased by one-third for loads that include wind or seismic forces. We recommend that all continuous footings at this site be reinforced top and bottom with No. 4 reinforcing - - 16 Project No. 59207A-SIOl - Woodward-Clyde Consultants bars, and that the concrete slabon-grade floors be rein- forced with a 6x6 lo/10 welded wire mesh placed at the midpoint of the slab. To reduce the possibility of soil moisture migrating upward through the concrete floor slab and living areas, we recommend that a lo-mil plastic mem- brane, lopped at least 6 inches at all joints and edges, be placed over the soil subgrade. The membrane should be covered with 4 inches of moistened sand to protect it against puncturing and to assist in curing the concrete. Excessive watering or ponding of water in the sand should be avoided. Rough or Compacted Grade 4" min. concrete slab with 6x6 lO/lO WV mesh ~[~~~,, Y t : 1 .y ~4 la’-:;Ii :,“,:::~pl=tic membrane bli;i;;m 12’2 Minimum 1 17 - Project No. 59207A-SIOl 1 T 1 1 T T T T T .r T Woodward-Clyde Consultants These recommendations are intended to reduce the effects of heaving and not to prevent heaving. Foundations placed on expansive soils should be expected to heave. Wall Pressures Unrestrained retaining walls (those not restrained from movement at the top), that have natural sloping ground surfaces of 2 to 1 (horizontal to vertical), can be designed for an active equivalent fluid pressure of 60 pcf. Unre- strained walls having level backfill surfaces can be design- ed for an active equivalent fluid pressure of 40 pcf. In order to resist lateral forces, friction between the bottom of the footing and underlying soil may be used. We recom- mend a friction factor of 0.4. If passive pressures are desired, we recommend a passive equivalent fluid pressure of 300 pcf. The top 12 inches should not be used in passive calculation unless this area is covered by a flood slab or pavement section. For our calculations, we assumed native soils would be used as compacted backfill, and wall heights would be 10 feet or less. Drainage should be provided to prevent excessive buildup of hydrostatic pressures behind walls. Pavements For the preliminary design of pavements, we have used the following assumptions: 18 I T T T T 1 1 1 1 1 1 1 1 1 I - - Project No. 59207A-SIOl Woodward-Clyde Consultants Subgrade R-values: 15 to 25 Subgrade material: compacted native soils Base R-values: 78 minimum Base material: Case 2 aggregate (State specs) Access Roads TI: 5.0 Parking area TI: 4.5 The following table presents our pavement section recommendations: PAVEMENT USE TI THICKNESS - AC Base PCC - - R=15 R=25 R=15 R=25 Driveway 5.0 3" 3" 8” ,+,, em -- Parking 4.5 3 " 3" 6%" 5" -- -- Dumpster Apron 5.0 -- -- -- -- 6 " 6 " We also recommend that the subgrade be scarified to a depth of 6 inches, watered as required, and compacted to a minimum of 95 percent of maximum laboratory density, as determined in accordance with ASTM Test Method No. D1557-70, prior to placement of base material. Whenever loose mate- rials are encountered to greater depths, they should be removed and recompacted. We recommend that Class II aggre- gate base conform to the State of California Standard Spec- ifications (January, 1978), Section 26. The asphalt should also conform to state specifications Section 39-2.01 for the asphalt, and Section 39-2.02 for the aggregate. The 19 I T T T 1 1 1 7 7 1 1 1 1 7 , - - Project No. 59207A-SIOl Woodward43yde Consultants foregoing subgrade R-values are preliminary and should be confirmed by performing R-value tests when access road and parking area subgrade soils become evident. We can present revised pavement sections in an addendum report, if necessary. GENERAL The recommendations made in this report are based on the assumption that the rock and soil conditions do not deviate appreciably from those found in the test borings and excavations. The recommendations are made for specific site development: if changes are anticipated or if any variations or undesirable conditions are encountered during construc- tion, the geotechnical consultant should be consulted for further recommendations. We recommend that the geotechnical consultant review the foundation and grading plans to verify that the intent of the recommendations presented herein has been properly interpreted and incorporated into the contract documents. The geotechnical consultant should also observe the site grading and the foundation excavations to verify that the soil and rock conditions used as a basis for design are appropriate. This firm does not practice or consult in the field of safety engineering. We do not direct the contrac- tor's operations and cannot be responsible for the safety of - - 20 Project No. 59207A-SIOl T T T T 1 1 1 7 1 - Woodward4lyde Consultants other thanour;'own personnel~on the site;:therefor~e, the safety of others is the responsibility.of the~.,contractor. The contractor should notify the owner if he considers any of the recommended actions presented in this report to be unsafe. Professional judgments represented in this report are based partly on evaluations of the~technical information gathered,~partly on our understanding of the proposed con- struction, and partly on our general experience in the geo- technical field. Our engineering work and judgments ren- dered meet the standard of care of our profession at this time. We do not guarantee the performance of the project in any respect. 21 T T T 1 1 1 1 1 1 1 1 - Project No. 59207A-SIOl Woodward-Clyde Consultants REFERENCES F. Beach Leighton, 1967, Geologic Report for Hosp Grove Planning Study Phase II, unpublished report. Ross, A., and R.V. Dowlen, eds., 1975, Studies on the Geol- ogy of Camp Pendleton and Western San Diego County, Calif- ornia: San Diego Association of Geologists, San Luis Rey Quadrangle Map. Wilson, K.L., 1972, Geologic Map of a Portion of the San Luis Rey Quadrangle, San Diego County, California, unpub- lished Master's Thesis. Woodward-Clyde & Associates, 1968, Soil Investigation for the Proposed Hosp Grove Development, Car&bad, California, report for Kamar Construction Company, unpublished. - 22 Loose, dry, brown silty fine to medium sand (SP), porous with abundant roots Very dense, locally very hard ripping with backhoe, dry to damp, reddish brown fine to medium clayey shnd (SC) LINDAVISTA FORNATION TEST TRENCH 2 I GRAPHIC SCALE (Feet) r ---k--- 0 10 For Legend. See Fiqure 2. I LOG OF TEST TRENCH 2 HOSP GROVE - BROADMOOR DIIAWW By: mrk CHECKED BY: ST/= PROJECT NO: 59207A-SIOl 1 DATE: 7-13-79 1 FIO”“EI)o: 3 WOODWARD-CLYDE CONSULTANTS r r - r r r ,-- -. Loose, dry, dark gray to black silty fine to medium sand (SM) with some clay and abundant roots Very dense, dry, reddish brown silty fine to medium sand (SM) massive with a few scattered small pebbles i LINDAVISTA FORMATION TEST TRENCH 3 GRAPHIC SCALE (Feet) I 0 5 10 For Legend, See Figure 2. LOG OF TEST TRENCH 3 HOSP GROVE - BROADMOOR DRAWNBY: mrk C"LCI(ED BV:JrF PROJECTHO: 59207A-SIOl 1 DATL: 7-13-79 1 FIO”~E no: 4 WOODWARD-CLYDE CONSULTANTS T f kxe, dry, light brown fine to coarse sand (SW) with a 2" black clayey sand (organic?) layer 2" below surface Loose to medium dense, dry to damp. dark brown silty fine to medium sand (SM) Medium dense to dense, damp, dark brown clayey fine to medium sand (SC) Medium dense to dense, damp to moist, brown silty fine to medium sand (SM) TEST TRENCH 4 r GRAPHIC SCALE (Feet) 0 5 10 r For Legend, See Figure 2. LOG OF TEST TRENCH 4 HOSP GROVE - BROADMOOR ~mvw IW m=k CHECKED BY: STF CI(OJECT NO: 5920-/A-SI01 DATE: 7-13-79 1 FIOunE)10: 5 WOODWARD-CLYDE CONSULTANTS 1 - T Loose to medium dense, dry, brown silty fine to medium sand (SM) with roots Very dense, damp, red brown clayey sand to sandy clay (SC-CL) Massive possibie slight ironoxide cement LINDAVISTA FORMATION TEST TRENCH 5 GRAPHIC SCALE (Feet) I I 0 5 10 r For Legend, See Fiqure 2. r I LOG OF TEST TRENCH 5 HOSP GROVE - BROADMOOR I DRAWW Ew mrk CHKKEDBY:STF ~RQ~ECTNO: 59207A-SIOl DATE: 7-13-79 1 FlOWlEWO: 6 r WOOOWARO-CLYDE CONSULTANTS Medium dense to dense, dry, brown clayey sand and sandy clay (SC-CL) with roots Very dense, damp, reddish brown clayey fine to medium sand (SC) with occasional pebbles up to 2" in size , massive LINDAVISTA FORMATION TEST TRENCH 6 T I GRAPHIC SCALE (Feet) T For Leqend. See Figure 2. I LOG OF TEST TRENCH 6 T HOSP GROVE - BROADMOOR I I ORAWWW: mrk C"CCIEDBI:ST,C PROJECTNO: 5'3207A-SIOL DATE: 7-13-79 FIOIMEIY): 7 T WOODWARD-CLYDE CONSULTANTS - -T Loose, dry, dark gray to @Jack silty clayey fine to medium sand (SM-SC) with roots Dense, damp, dark gray sandy clay (CL) -2- Dense to very dense, damp, brown clayey sand (SC) Very dense, damp, br brown clayey sand (SC) TEST TRENCH 7 7 I GRAPHIC SCALE (Feet) T I 0 10 For Leqend, See Figure 2. T LOG OF TEST TRENCH 7 HOSP GROVE - BROADMOOR DRAWN~.V: mrk CHECKED BY: JV ~RCUEGTNO: 59207A-SI01 1 DATE: 7-13-79 1 FlD"RELY): 8 I WOOOWARO-CLYDE CONSULTANTS 1 - - T Soft to stiff, damp, grayish brown sandy clay (CH-CL) Upper 1-2' contain roots, lower 1' mixture of gray-brown sandy clay and light yellowish white silty sand Dense, dry to damp, light yellowish white silty sand to clayey sand (SM-SC) Massive TERTIARY SANDSTONE TEST TRENCH 8 I- GRAPHIC SCALE (Feet) I I 0 5 10 T For Leqend. See Fiqure 2. I LOG OF TEST TRENCH 8 HOSP GROVE - BROADMOOR DRAWNBY: mrk CHECWDBY:J-rr PnOJECTNO: 59207A-5101 1 DATE: 7-13-79 1 FlO"REL*): 3 WOOOWARO-CLYDE CONSULTANTS Loose to medium dense, damp, light brown fine to coarse sand (SP) with occasional 1" pebbles, some bedding and faint cross bedding~parallel with slope, &ntains roots Dense to very dense, damp to moist, reddish brown silty clayey sand (SM-SC) Massive TEST TRENCH 9 T GRAPHIC SCALE (Feet) 5 10 For Leqend. See Fiwre 2 I I LOG OF TEST TRENCH 9 HOSP GROVE - BROADMOOR DRAWN BY: mrk CHECKED BY: 5V PRSJECT NO: 59207A-SIOI DATE: 7-13-79 1 FlO""EIY): 10 I WOODWARD-CLYDE CONSULTANTS - 1 1 1 1 1 1 ~7 Soft, damp. brovnvsandy Very dense, damp, white fine to medium sandy clay to clayey sand (CL4c) blocky with weathered block surfaces and abundant roots Very dense, damp, medium sandy clay white fine to to clayey sand (CL-SC), massive, friable TERTIARY SANDSTONE TEST TRENCH 10 GRAPHIC SCALE (Feet) 0-o For Legend, See Fiqure 2 I LOG OF TEST TRENCH 10 HOSP GROVE - BROADMOOR I DRAWIIBY: mrk CHEIXEDBY: jr,= ,~oJECTNO: 59207A-SIOl O*Tf: 7-13-79 I FIO""EWO: 11 WOOOWARO-CLYDE CONSULTANTS . 1 T -I 1 T - T -I - 1 T T Project No. 59207A-SIOl Woodward-Clyde Consultants APPENDIX A FIELD INVESTIGATION Two exploratory test borings were drilled at the approximate locations shown on the Site Plan,and Geologic Map, Fig. 1. The drilling was performed under the direction of our firm on July 11, 1979, using a 36-inch diameter, continuous-flight Watson 55 power auger. In addition, ten test trenches were excavated by a 24-inch wide, tractor- mounted backhoe also at the locations shown on Fig. 1. Samples of the subsurface materials were obtained and carefully sealed to preserve the natural moisture con- tent of the sample. The sample was then returned to the laboratory for examination and testing. The location and elevation of the ground surface at each test boring location was estimated by reference to available topographic maps. T T T T I- T T 23 1 1 1 1 T 'T T T T T T T T r r r r r - Location DEPTH TES TDI IN - FEET l MC ’ ‘DD - 12 110 T 3 Boring Number Elevation I SAMPLE UMBER I SOIL DESCRIPTION 1 2 Very dense, damp, brown silty sand (SI.1) SOIL CLASSIFICATION soit c,arsitiurionr am bsed on the ““itied soil Clardiution S”rtem and include colon. moirture and consistency. Field descriptiom have hem mcdified fO reflect results Of laboratory analYsepI **re *pproprme. OISTURBEO SAMPLE LOCATION ; obtained b” COlleCting tile auger cuttings in a plaltic or cloth bag. - DRIVE SAMPLE LOCATION MODIFIED CALIFORNIA SAMPLER sample With recorded bbw per ‘0.x was obtained with a Modi‘icd California ckiw rampIer ,I’ inside diemeter. 2.5” oursida diameter, lined With Iample WbCI. The sampler was driven inKI the IOil at *he k.ttom 0‘ the hole Wirh a 140 pound tlsmmr f*llong 30 inches. INDICATES SAMPLE TESTED FOR OTHER PROPERTIES GS - aran size Oirtrib”tlo” CT - Conrolidamn Ta%\ LC - Labarataw Comoanion “CS - “nmn‘incd Comrerrion Terr Test PI - Atterberg Limitr TM ST - LOaded Swell Test cc - Confined Comprerrion OS - oi,ecct Shear Test TX- Trimid Comprc*rlon Test NOTE: I” fhil col”rn” the results 0‘ these Wl,S ma” be recacled where app,ic*,c. BLOW COUNT Number Of blows needed to advsnes UrnpIer one toot or as WldlcMed DRY DENSITY Pwdr per Cubic F0.x MOISTURE CONTENT Pernn, 0‘ my Weight NOTESON FIELD INVESTIGATION 1. REFUSAL indiOl” ms irnbiliry 10 axlerd .xca.Y*tion. Plmicaw. viol equipINn, being “sad in the invert~gatio”. KEY TO LOGS HOSP GROVE-BROADMOOR DRAWNBY: MRKI c,,s.xEOBY: STFi ~RQIECTNC.: 59207A-SIOl 1 DATE: 7-13-79 1 WQURENO: A-l WOOOWARO-CLYDE CONSULTANTS 7 1 I 1 1 1 1 -I -I 1 1 1 I -, -, -, - - - - r 0, - ‘DO - - - - ‘8C - - I - )THEI raT.3 - Boring 1 Approximate El. 86' SAMPLE "UMBER SOIL DESCRIPTION Very dense, damp, white to light yellowish white coarse to fine clayey sand to sandy clay (SC-CL) TERTIARY SANDSTONE Root along possible joint with iron oxide stain - Attitude 65. N50E Roots - Attitude 40* N50E Very dense, damp to moist, light rusty yellow silty fine to coarse sand to clayey sand (SM-SC)- Attitude 15' S45E TERTIARY SANDSTONE Hard, damp, olive gray sandy clayey silt to silty clay (ML-CL) - irregular contact, approximate attitude 17' N85E. possible interbed-in TERTIARY SANDSTONE Bottom of Hole '~o,daw,i~tiono‘.~mbo,.,ye ~,gurc A-l LOG OF TEST BORING 1 HOSP GROVE - BROADMOOR DRAWNBY: mrk C"ECKED w: STF PRoJECTNO: 59207A-SIOl 1 DATE: 7-13-79 ] FIGUREIIO: A-2 WOOOWAAD-CLYDE CONSULTANTS 1 1 ‘I I I I -i 1 1 1 1 1 1 1 1 1 1 1 - ;r D‘ - ‘DO - - Boring 2 ADDrOXimate El. 95' SAMPLE ,“MBER I SOIL DESCRIPTION I soft, damp,~ brow-+ gray to-olive ,gray,.: siltv clav (CL)" TERRACE DEPOSITS Soft to medium stiff, damp, light olive \ to rusty brown fine sandy silt (ML) with lenses of fine sand - Attitude 4' TERRACE DEPOSITS Stiff, damp, light brownish gray fine sandy silt (ML) with clayTERRACE DEPOSITS II Very dense, damp, light olive gray fine sandy silt to silty sand (ML-SM) mottled with rust color TERRACE DEPOSITS Very stiff, lisht olive qrav silty clay (CL) with fine sand TERRA& &POSI!CS - stiff, damD. arav mottled with rust color E clay (crkij - - TERRACE DEPOSITS Stiff to very stiff, olive gray fine sandy Stiff to very stiff, olive gray fine sandy silt (ML) TEP,RACE DEPOSITS Dense, damp, gray fine to coarse sand (SP) with small pebbles and sravel - Attitbde 5' TERRACE DEPOSITS Very dense, dry to damp, white silty fine to coarse sand (SWTERRACE DEPOSITS Very dense, damp, light yellowish gray silty fine sand to sandy silt (SM-ML) with lenses and pockets of fine to medium silty sand, fine sand and silt - Attitude 3-9' S6OW - dip in part due to channeling TERRACE DEPOSITS Very stiff, damp, brown fine sandy silt (ML) TERRACE DEPOSITS Very dense, damp, light gray silty fine sand (SM) TERRACE DEPOSITS CONTINUED ON NEXT PAGE -6X derui,,ttO” Of lytidl. P(L FiglC.3 A-1 LOG OF TEST BORING 2 HOSP GROVE - BROADMOOR DR4WNBY: mrk CHECKED BY: srf= PROJECT HO: 59207A-SIOL DATE: 7-13-79 1 FIGURE No: A-3 WOODWARD-CLYOE CONSULTANTS 1 -I 1 I 1 1 'l -1 1 1 1 1 1 -1 1 1 1 ~1 -, . - L,-_ - ‘BC - - iiHEi EST!3 - iAMPLE IUMBER 1-5 [ t-6 [ x-7 Boring 2 (can’t) _ _ ,~_. se61’~ ~E~SC’RIPTION I - - ~.. J Very stiff, damp, flight gray fine sandy silt I TERRACE DEPOSITS V&y d&&&,e ~‘&mp;~ -iilty~ fine *ana CSM) TERRACE DEPOSITS Very dense, damp, light gray fine to coarse _ ~'-Sandy-XSP). Abundant trust colored streaks - \ Attitude approximately 3' S6OW TERRACE DEPOSITS Silty - 1" gray silty clay bed Very dense, damp, light yellow brown, -browns-t~~rusty.brown finesandy silt and silty fine sand (ML-sM) ~._ TERRACE DEPOSITS . 1 Medium to coarse Very stiff to stiff, moist, light olive gray mottled with rust color fine sandy~ silt (ML) - Attitude 4* S6OW - diu in Dart _ _ due to channeling TERRACE DEPOSITS L Dense to very dense, moist, light gray to v rust cola fine to medium sand (SP) - 7 Attitude 35' S6OW - may be channel feature TERRACE DEPOSITS Not logged Material cave in Bottom of Hole *For de,cript,~n o‘ryrni,o,s, see Figure A-l I LCG OF TEST BORING 2 (Con’t) HOSP GROVE - BROADMOOR DRA*YN~Y: mrk CHECL(EDBY: 5r~ PRQIECTNO: 59207A-SIOl DATE: 7-13-79 1 FIG”Rf No: A-4 WOODWARD-CLYDE CONSULTANTS Project No, 59207A-SI01 1 1 1 - 1 1 1 1 1 1 1 1 1 -1 - 1 1 -1 Woodward-Clyde Consultants APPENDIX B LABORATORY TESTS The materials observed in our test borings were visually classified and evaluated with respect to swelling characteristics. The classifications were substantiated by grain size analyses and determination of plasticity char- acteristics of representative samples of the soils. Fill suitability tests, including compaction tests and expans- ibility characteristics tests, were performed on samples of the probable fill soils. Swelling characteristics were estimated by per- forming loaded swell tests on undisturbed and compacted samples. The grain size distribution curves are shown on Fig. B-l. The fill suitability tests, including the loaded swell tests, are reported on'Fig. B-2. 24 T 7 - 1 1 - 1 1 I 1 -1 - - - - - - COBBLES GRAVEL I SAND COarSe Fi na Coarse Medium I SI LT and CLAY Fine 1 Mesh Opening - Ins Sieve Sires Hydrometer Analysis I I 1 I loo 76 32 IO 16233040 Go 60 70 60 50 w 0 IO 20 30 w 50 60 70 loo 50 IO.0 5.0 1.0 0. I 0.05 0.01 0.005 0.001 GRAIN SIZE IN HILLIHETERS ‘LL - Liquid Limit ‘PI - Plasticity Index GRAIN SIZE DISTRIBUTION CURVES HOSP GROVE - BROADMOOR DRAWN BY: mrk CHECKED BY: 5f.c PROJECT NO: 59207A-SIOl DATE: 7-13-79 FI(I”RE No: B- 1 WOODWARD-CLYDE CONSULTANTS PLASTICITY CHARACTERISTICS -- SILT 6 CLAY Liquid Limit. % Plasticity Index; % ” Classification by Unified Soil ,O MECHANICAL ANALYSIS - 1 DIRECT SHEAR TEST DATA 1 1~ I I Apparent Friction Angle. degrees 1 I I I SWELL TEST DATA 10 20 30 40 LABORATORY COMPACTION TEST Initial Dry Density, pcf 113 111 Initial Water Content. % 9 12 Final Dry Density. pcf 113 111 Final Water Content, % 14 18 Load. psf 160 160 -- Swell. percent 0 0 LABORATORY COMPACTION TESTMET"OD: ASTM-D 1557-70 FILL SUITABILITY TESTS HOSP GROVE - BROADMOOR DRAWNBY: sh 1 CHECKEDBY: 1 P~NF~T ~0. 59207A-~101 1 n.rE: 7-16-79 I Sldl,“E YOI R-2 APPENDIX C I I- r r r I -. - _- .- - SPECIFICATIONS FOR CONTROLLED FILL I. GENERAL These specifications cover preparation of existing surfaces to receive fills, the type of soil suitable for use in fills, the control of compaction, and the methods of testing compacted fills. It shall be the contractor's responsibility to place, spread, water, and compact the fill in strict accordance with these specifications. A soil engineer shall be the owner's representative to inspect the construction of fills. Excavation and the placing of fill shall be under the direct inspection of the soil engineer, and he shall give written notice of conformance with the specifications upon completion of grading. Deviations from these specifica- tions will be permitted only upon written authorisation from the soil engineer. A soil investigation has been made for this project; any recommendations made in the report of the soil investigation or subsequent reports shall become an addendum to these specifications. II. SCOPE The placement of controlled fill by the contractor shall : . include all clearing and grubbing, removal of existing unsatisfactory material, preparation of the areas to be filled, spreading and compaction of fill in the areas to be filled, and all other work necessary to complete the grading of the filled areas. III. MATERIALS 1. Materials for compacted f,ill shall consist of any material imported or excavated from the cut areas that, in the opinion of the soil engineer, is suitable for use in constructing fills. The material shall contain no rocks or hard lumps greater than 6 inches in size and shall contain at least 40% of material smaller than l/4 inch in size. No material of a perishable, spongy, or otherwise improper nature shall be used in filling. 2. Material placed within 24 inches of rough grade shall be select material that contains no rocks or hard lumps greater than 6 inches in size and that swells less than 6% when compacted as hereinafter specified for compacted fill and soaked under an axial pressure of 160 psf. - - - -- - .- .- 3. Representative samples of material to be used for fill shall be tested in the laboratory by,the soil engineer in order to determine the maximum density, optimum moisture content, and classification of the soil. In addition, the soil engineer shall determine the approximate bearing value of a recompacted, saturated sample by direct shear tests or other tests applicable to the particular soil. ~. 4. During grading operations, soil types other than those analyzed in-the report~of the soil investigation may be encountered by the contractor. The soil engineer shall be consulted to determine the suitability of these soils. IV. CONPACTED FILLS 1. General :~~:_.:~ ~. ~.:.~ .'~ ~. :. . . (a) Unless otherwise specified, filly material shall be compacted by~the. contractor while at a.moisture content near the optimum moisture content and to a density that is not less than 90% of the maximum dry density determined in accordance with ASTM Test No. D1557-70, or other density test methods that will obtain equivalent results. (b) Potentially expansive soils may be used in fills below a depth of 24 inches and shall be compacted at a moisture content greater than the optimum moisture content for the material. 2. Clearing and Preparing Areas to be Filled (a) All trees, brush, grass, and other objectionable material shall be collected, piled, and burned or otherwise disposed of by the contractor so as to leave the areas that have been cleared with a neat and finished appearance free from un- sightly debris. (b) All vegetable matter and objectionable material shall be removed by the contractor from the surface upon which the fill is to be placed, and any loose or porous soils shall be removed or compacted to the depth shown on the plans. The surface shall then be plowed or scarified to a minimum depth of 6 inches until the surface is free from uneven features that would tend to prevent uniform compaction by the equip- ment to be used. (c) Where fills are constructed on hillsides or slopes, the slope of the original ground on which the fill is to be placed shall be stepped or keyed by the contractor as shown on the figure on Page 4 of these specifications. The steps shall extend completely through the soil mantle and into the underlying formational materials. - - 2 - . . ‘. - - - - - -- - ,- - -~ - (d) After the foundation for the fill has been cleared, plowed, or scarified, it shall be disced or bladed by the contractor until it is uniform and free from large clods, brought to the proper moisture content, and compacted as specified for fill. 3. Placing, Spreading, and Compaction of Fill Material (a) The fill material shall be placed by the contractor in layers that, when compacted, shall not exceed 6 inches. Each layer shall be spread evenly and shall be thoroughly mixed during the spreading to obtain uniformity of material in each layer. (b) When the moisture content of the fill material is below that specified by the soil engineer, water shall be added the contractor until the moisture content is as specified. (c) When the moisture content of the fill material is above that specified by the soil engineer, the fill material shall be aerated by the contractor by blading, mixing, or other satisfactory methods until the moisture content is as specified. (d) After each layer has been placed, mixed, and spread evenly, it shall be thoroughly compacted by the contractor to the specified density. Compaction shall be accomplished by sheepsfoot rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of acceptable com- pacting equipment. Equipment shall be of such design that it will be able to compact the fill to the specified density. Compaction shall be continuous over the entire area, and the equipment shall make sufficient trips to insure that the desired density has been obtained throughout the entire fill. (e) The surface of fill slopes shall be compacted and there shall be no excess loose soil on the slopes. V. INSPECTION 1. Observation and compaction tests shall be made by the soil engineer during the filling and compacting operations so that he can state his opinion that the fill was con- structed in accordance with the specifications. 2. The soil engineer shall make field density tests in accordance with ASTM Test No. D 1556-64. Density teStS shall be made in the compacted materials below the surface where the surface is disturbed. When these tests indicate that the density of any layer of fill or portion thereof is below the specified~density, the particular layer or portion shall be reworked until the specified density has been obtained. - . . ,.I 1’. - - -. - - -. .- - - - VI. PROTECTICN OF WORK 1. During construction&e contractor shali properly grade all excavated surfaces to~provide positive drainageand prevent ponding of water. He shall control surface water to avoid damage to adjoining properties or to finished work on the site. The contractor shall take remedial measures to prevent erosion of freshly graded areas and until such time aspermanent drainage and erosion control features have been installed. 2. After completion of grading and when the soil engineer has finished his observation of the work, no further excava- tion or filling shall be done except under the observation of the soil engineer. or sliding does not occur ~. Renuve all topsoil NOTES: .See note' The minimum width "B" of key shall be 2 feet wider than the compaction equipment, and not less than 10 feet. The outside edge of bottom key shall be below topsoil or loose surface material. Keys are required where the natural slope is steeper than 6 horizontal to 1 vertical, soil engineer. or where specified by the note 4 - I ’ , - APPENDIX D SPECIFICATIONS FOR SUBSURFACE DRAINS - -~ -. -. -. - - .- - - - - I .' DESCRIPTION Subsurface drains consisting of perforated corrugated metal pip' shall be installed as shown on the plans in accordance with these specifications, unless otherwise specified by the engineer. II MANUFACTURE Subsurface drains shall be manufactured in accordance with the followin- requirements. Perforated corrugated metal pipe and clay tile shall conform tc AASHO Designation Ml36 and ASTM Designation C4, respectively. III. FILTER MATERIAL Filter material for use in backfilling trenches around and over drains shall consist of clean coarse sand and gravel or crushed stone conforming to the following grading requirements. Sieve Size 1" 3/4" 3/8" ;: #30 #50 #200 _Percentage Passing Sieve 100 90 -100 40 -100 24 - 40 18 - 33 5 - 15 o- 7 o- 3 This material generally conforms with Class II permeable material in accordance :iith Section 68-1.025 of the Standard Specifications of the State of California, Department of Transportation. LAYING Trenches for drains shall be excavated to a minimum width equal to the outside diamteer of the pipe plus 1 foot and to the depth shown on the plans, or as directed by the engi*leer. The bottom oi the trench shall then be covered full width by 4 inches of filter material and the drain pipe shall then be laid. Unless otherwise specified, perforated pipe shall be laid with the perforations at the bottom and sections shall be joined with couplers. The pipe shall be laid on a minimum slope of 0.2%. After the pipe has been placed, the trench shall be back- filled with filter material to the elevation shown on the plans, or as directed by the engineer. TYPICAL SECTION SUBSURFACE DRAINS IN DRAWS -. -. - Compacted Fill as required . , 4-inch diameter 2' 4 \b!$j --+ / / i ~-c--~--lo' fin le - - - - . .,* ‘> - -. -. -. - _- - .,- Project No. 59207A-SIOl ATTACHMENT II 15 Pages - - .I _ :’ - - - - .-. -. -. -- - -- _- .- ,- - - - - Fiq. I 100~ 150 A ,-*' /‘I k .-- ‘\ I’ --- ; ,w-- io l ‘-- 1 ; :-;A I il. cc- 7 I' 'fi'w ) p'"; 12 f' ' (- ,!9 J-y 8 y-f \/'7 ,) . ,". I‘;' h 'L/h, 7 /I Lx,“* +f-+/. _ : ,/L---;=--' 5-1 / I -9 r(, 5. <,5' /' . :?a / ~,~~~~~~, ! / /' , Legend Indicates approximate location of test l boring. ,0"200., H indicates approximate existing ground surface contour. pJ indicates approximate limits of Bay Deposits.. n lndjcates approximate area of alluvial WOODWARD, CLYDE, SHERARD E ASSOCIATES HOSP WOVE PROJECT KO. 67-223 .* 1. - . - - - - -- -~ -. -. _- _- - .-- ,- - - - - Fio. 2 i5 Wing I VIC=, 5 DO= 92 DC= 17 WC: 25 DD= 91 Elk IS' .vKk ,I7 DE=106 Bti 42 ':i::::i;:l, Pedi~+dense, dzmp, light red brosm $j& silty s;qd (34) (porous) ~ ,;:f:.$/i:j.y::: Very stiff;wist, dark brown sandy kf/// ~~~~~~&~d~j olive clayey - - 1.111, #/ Dense, danp, light olive sandy i?-ll& silt (ML) Boring 2 WC= 6 DE=IoI , dznp, light brom'silty Bc- I8 DS: @= 26 ,"'a: #dim-dense, &qp, brown silty c- 0 2 ;;$;;';;; sand (%) .V,& (j =+ DE I 132 EC= I3 ;;;;;;;;f$; We ,6' =, 3 ;;;;g; yp, 10 -i(i:jgq BC; 26 _ ~~ Dense, waist, dark brown silty \',c= g -- .:/_;;;:::::;:: sand (%) DD= I I 5 h,,:::.:::..::.::~ I) &j; & t<ed i urn-dense, d&n?, brow clayey 5 :::::~:;x.: ~~' sand (SC) K= 22 'I:il:i?i:: f&j Very stiff, moist, olive brown sandy yg clay (CL) ,@I 6 %,‘> EC= 25 +- gg I; , ‘7 (+p, F-:,, Bc= 6. ,, ,~i, ::“” Dense, saturated, light brol+m silty I::;::;.l_:_i 1 smd ( Si) WOODWARD, CLYCC, SiERARD & ASSCCIAXS Note: For Legend, see Fig. 5. I LOGS OF TEST EORINGS I h 2 ?A!-'!2 HOSP GWE PROJECT KO. 67-223 - -. - - - -. -. -. __ _- - - - bring 3 O- 5- ,O- .5- Do- !5- IO- I5- w-- ~Mc= 5 DD= 69 EC ,q Lc= 4 DD=IOI EC= 22 EC= 26 BC= 32 ::;::::::::::.::: 5 ~~~~ ;i;i::;,;if.f!:f; Note: For Legend, see Fig. 5. 1 VICD!XIARD. CLYDE. SYEXRD S ASSCC!ATES t!OSP GWVE Pr?O?ECT P;O. 67-223 _.. _.. ?-u-F!2 ID, LOG OF TST iXRI!IG 3 Ewing 4 & Loose, damp, light bro$;m silty ~:s:-:,, \sand (3) Medium-dense, damp, brow silty sand ($4) with scattered gravel w= a - ~“’ “‘.:‘:+ DE 1 CQ 2 ?& _ ~::.::::i~ti ge 27 $;;i-‘; ::/:; -::::,,: ist, olive brow ist, olive silty ~,~, ..~.. Note: For Legend, see Fig. 5. 1 V!GDX!ARD. CLYDE, WERARD & H>> - ,’ ’ - ; - - - - - - - -,. -_ _- -- - - - - - - Fin. 5 0, 5- io - i5 - Xl- Boring 5 kdium-dense dump, light brown silty sand (S?4) (Porous) DD=lOi Fe I9 Wk. 5 DD=l09 Bc= 40 - @&( Dense, damp, red brw silty sand Bc; 45 w:i:;:ig - -1 y”“‘. WC = Water Content in percent of dry weight. DD = Dry Density in pcf. BC : Number of blows by IW-Lb. hammer falling 30 inches to drive sampler I2 inches. Sampler Data: ID = 2.0", OD = 2.5". UCS = Unconfined Expressive Strength in psf. DS = Dire&Shear Test Data: $ = Angle of Apparent Friction-in degrees. A$ - C = Apparent Cohesion in psf. - V!ater Level at time of drilling. (Z-4) = Group classification symbol in accordance with the Unified Soil Classification System. WOODVIARD, CLYDE,’ SHERARD 8, ASSOCIATES I LOG OF TEST EDRING 5 HOSP GROVE ~PJDJECTNO. 67-223 ~~~~ ~~~_ ~ - . ‘I - ! - - - - - - - - - __ _- - .- - - 0 5 10 I5 20 25 30 35 40 43 Wing 6 dznp, light brown silty sand Medium-&nse, \sand (SC) damp, brown clayey damp, red brwr,silty t&$iurn-dense, sand (W ( s1 i ghtl y porous) f, moist, brown sandy clay WC- 2 DD-IOI BC- 25 :?ii;$ Mediumdense, rraist to saturated, pi& a - ~{~@$$ 01 ive clayey sad (SC) DD= I 0 I BG 22 "i;,;j& ::X+&; Bc= I7 & Stiff, moist, olive sandy clay 4 (CL) Stiff, moist, dark brow sandy clay Note: For Legend, see Fig. 5. WOOZXVARD, CLYDE, SMERARD 2, ASSOCIATES LOG OF TEST WRING 6 HOSP GROVE PROJECT NO. 67-223 - $1 -.\ - - - - - - - -,. - -_ - .~ .- - - - ( I- S-~ Wing 7 ;";:':I Ked~ium-dense, da%;lp, icd 6&n si lty sand (3) ;;;;;i-, Very detiSe,--danpi -itid-brow clayey ;i:&; sa,,d (SC) 1 bring 8 kdim-dense, dznp,, red brown silty , dads, red brown silty Note: For'Legend, see Fig. 5. ‘X?=!X.X~D, CLYDE, SHCSA.PD ; ASSOCIATES LOGS OF TEST EZINGS 7 & 8 H?SP C.xl'/E Pil@JECT X0. 67-223 - .’ -? - - - - - - - - -. -. - - .- .- - - Note: For Legend, see Fig. 5. I 0 I 4 Coring 9 Iskdim-dense, dmp, bro'm silty sa-,d porous _] :j;f;j:ij:; Very ,, me, ;I, 1; -2__;;:;;i$ sand (SC) dmp, red brom clayey BC= 60 WC= ~6 - ':;:-::::::::: Very dense, daq, red brolln silty DD= I I 2 - -$:ii:;i;i'i sad (s,,) 3 ::_::,:::::::: Bc45/6" - ~+ Boring IO se, danp, red brown silty ard, damp, red brown sandy clay nse, damp, red brown silty hring II dmp, br& silty oorous) Very,dmse, dqo, red brom silty \smd (%I) (cmented) 1 V!CDWA8D, CLYDE, S:-IE?AgD .T, ASSOCIATES LGGS OF TEST EZ?l:lGS 9 TH?CUC'i II !!OSP GZWF: PWJECT NO. 67-223 - - - - IO Boring 12 bkdiudense, damp, red bro*m si Ity ,&:,:i;, . ..~1'.:, ~~Jm~* Fgrave] ~...~.. '.~ ___.... ._ E99” _ ~ y ~:~~ & 60 ~~~~~ Deeq damp, olive silty fine sand -1 :.:,:..,:.~:.:: Note: For Legend, see Fig. 5. I VIGDDWARD, CLYDE, SUERARD & ASSiXATES - 1’ - :; - . - - - - - - -. - - -. _- _- .- - - 0 5 i0 15 20 25 @orin3 13 ’ t’;CDD”“‘?D, CLYDE. SHL?AED & ASSOCIATES . ..3. LCG OF TEST iGRlEG 13 7-!I-CQ HOS? G?clvE PQJECT !!O. 67-777 Loose, dq, brcwn silty fine sand \"c; 4 1 , Dense, dmp, bran silty sand Ekl IO BC= 61 J ~grave, ,E,:,;:--ii;z, Dense, d-m?, 01 i ve si 1 ty sand ,;;j& ( 2.4) H& 8 - i:;:$:j Db,22’ ~~ BI3#0/6” J- ;~;;;;j;;$ A?-.~ @= 39 ‘:;j k535 -_ ~$;;':;:: :::::::::::::,~ .,.. :::::/:::/;,:;; Note: For Legend, see Fis. 5. ,‘~m . - ) - - - - - ._ -~ -. _. _- - _- - - - 0 5 IO I5 20 25 3l 35 40 Boring II) Boring II) .;;i;& Very lcose, moist to wet, brorvl .;;i;& Very lcose, moist to wet, brorvl ~::: ::~.~,'.'~~ ~::: ::~.~,'.'~~ ::.+ ,, ::.+ ,, s j 1 ty sad ($1) s j 1 ty sad ($1) " ~~~ ! We 23 - ;;:s:~:, Very~lcose, ~saturated, gray brown GC'=106 ( _ ?&:' .::_:::/: ;::: si ]ty s& ( QJ) Bti~3 - Ia%; Fins, saturated, dark gray sandy UC3=17GO=-Y~ WC=.'9 L ,+ & clay (CH) D~III _ ~~~--:',-i:ii: Loose, saturated, light gray bra WC= 64 DD= 63 clayey sand (SC) EC= I Very soft, saturated, light gray brova si '9 c'ay (4 case, saturated, olive brown to c,ayey sa"d (~~~,ccsc) Medium-dense, saturated, brm sandy clay (CL) WC= 20 DG=IlO ~:::::i: ;i, Loose to mad i urndense, saturated , brobn si ]ty sand (S.j) with lenses of COarSe sand ( sp) continued on next page, Fig. 12. Note: For Legend, see Fig. 5. VIODDP1ARD, CLYDE, SHERARD & ASSOCIATES - -. -. -. ,._ .- bring I$, continued WI -7 ---$~I--‘~----- see FiG.11 last layer. 45 50 K= ,i6 m-dense, saturated, imy Drkll6 (Bi ) EC= 70 saturated, brosn si lty sand 55 :::;:-::.::$i::: ::g;;;i; 60 t,&jiu;;t&nse, saturated, olive bro\q, silty to clayey sand ($+S/rsc) 65 70 75 80 \Kk I6 saturakd, olive , DO= I 15 & yo Dense, saturated, brown silty sand ;:~: ::~: ,~:~ kf= I6 - :/i:,,:i-,,':': DD= I ;3 .;,; :, Very dense, saturated, brow silty EC=ICO b,C:b' send (9) with gravel Fig. 12 :li * I. l!ote: For Legend, see Fig. 5. l:‘OOC~:.‘XO, CL’YDE, SHE3XD & ASSDCI,?.T,CS LOG OF TEST FxXl::G I4 LOG OF TEST FxXl::G I4 I u, -Y" I P.! I HOS? G~?OVE PROJECT 13. 67-22: ?-LF? I P.! - .~ . .‘., . . - . - - - -~ -. -. _,. - _- _- - .-~ .- .- - - 25 30 bring 15 \I& ,L! 11, flD= Sj' EC= I4 1 ig,,t brown Loose to medium-dense, saturated, light brow silty sand (S!4) with BC= 20 Z<Fd: ,;~~ s 0 1;+ """ """"~ Ked i m-dense, saturated , g ray brw n clayey sad (SC) Siiff, saturated, gray sandy clay ,~:;;:;~!:!:;:- kd i un-den se, satu rat& , g ray s i 1 ty $jl_: sad ($4) ::::.::/:I /::~I, Note: For Legend, see Fig. 5. r I~.'C02',?:,20. CLYDE. SHE?.RD & ASSOCIATZS LCG OF TEST EORI::G 15 %OSP GROVE PWECT ti0. 67-223 3-5-55 I C' - *.’ .> .c - . - - _- - -. - - - _- - - - .- .- - - - i -: Paring 16 Very loose to loose, mist, dark brown silty sand (%I) 3 Stiff, mist, olive bro+m su,dy 6 :~~~, BC= 65 -j-- ;::;;i:-iii:i p:!/ Dense, danp, 01 ive silty to clayey :;$& sad ( s,- SC ) . Be 6gpm Hard, dnp, olive clay (CH) /:;::;;.;;,j. continued on next pase, Fig. 15. Note: For Legend, see Fig. 5. V.COC:'.'A%& CLYDE, SHEXWD e, ASSOC!,XZS I LOG OF TEST EO4l::G 16 HXP GROVE PRXECT PO. 67-223 3-5-69 CC! ’ ,,<‘<A 8 ., - - - - )- .!, bring 16, continued ----- see Fig. 14, last layer. Note: For Legend, see Fig. 5. LCG OF TEST %81:!G 16 sp p$\/E *, PK'JECT HC. 67-223 ~w23 L.C,I