Loading...
HomeMy WebLinkAboutCT 01-06; CALAVERA HILLS II VILLAGE X; INTERIM RPT OF GEOTECH INV CALAVERA W-X-Y;INIERIM REPORT OF GBOTBCHNICAL INVESTIGKnCN CALAVERA HEIOnS VILLACSS W-X-Y TAMARACK AND COUL^GE BOULEVARD CARLSBAD, CALIFC/NIA PREPARED FOR: Lyon CanminitJ.es, Incorporated 4330 La Jolla Village Drive, Suite 130 San Diego, CaliforrLLa 92122 PREPARED BY: Southem Califomia Soil & Testing, Inc. Post Office Box 20627 6280 Riverdale Street San Diego, Califomia 92120 SOUTHERN CALIFORNIA SOIL AND TESTING, INC. 62B0 RIVERDALE ST. SAN DIEGD, CALIF. 92)20 • TELE 280-4321 • P.O. BOX 20627 SAN DIEGO. CALIF. 92120 67B ENTERPRISE ST. ESCONDIDO. CALIF. 92D26 TELE -7 ^ 6 ' A S 4 A May 15, 1990 Lyon Coimunities, Incorporated 4330 La Jolla Village Drive Suite 130 San Diego, Califomia 92122 SCS&T 9021049 Report No. 1 ATTENTION: Mr. Geor(ge Haviar SUBJECT: Interim Report of Geotechnical Investigation, Calavera Heights Villages W-X-Y, Tamarack and College Boulevard, Carlsbad, Califomia. Gentlsnen: In accordance with your request, we have conpleted an interim geotechnical investigation for the subject project. Vfe are presenting herewith our findings and recommendations. In general, found the site suitable for the proposed developnent provided the reconmendations presented in the attached report are followed. If you have any questions after reviewing the contents contained in the attached report, please do not hesitate to contact this office. This opportunity to be of professional service is sincerely appreciated. Respectfully submitted,^— SOUIHEWI CMto)RNIA}sOn/ & l-^STING, INC DBA:JRH:KAR;inw cc: (2) Submitted (4) Hunsaker and Associates (1) SCS&T, Escondido SOUTHERN CALIFORNIA TABLE OF CCNIENTS PPOE Introduction and Project Description 1 Project Scope 2 Findings 3 Site Description 3 General Geology and Subsurface Conditions 3 Geologic Setting and Soil Description 3 1) Basement Complex-Jurassic Metavolcanics and Cretaceous Granitics (Jmv/Kgr) 4 2) Santia(30 Fonnation (Es) 5 3) Older Quatemary (Pleistocene) Alluvium (Qoal) 5 4) Younger Quatemary (Holocene) Alluvium (Qyal) 5 Tectonic Setting 7 Geologic Hazards 7 Groundshaking 8 Seismic Survey and Rippability Characteristics 8 General 8 Rippability Characteristic of Granodioritic Rock 12 Rippable Condition (0-4,500 Ft. /Sec.) 12 Marginally Rippable Condition (4,500 Ft./Sec.-5,500 Ft./Sec) 13 Nonrippable Condition (5,500 Ft./Sec. & Greater) 13 Rippability Characteristics of Metavolcanics and Associated Hypabyssal Rocks and Tonalitic Rocks 13 Rippable Condition (0-4,500 Ft./Sec.) 13 Marginally Rippable Condition (4,500-5,500 Ft./Sec.) 14 Nonrippable Condition (5,500 Ft. Sec. & Greater) 14 Seismic Traverse Limitations 14 Groundwater 15 Conclusions and Recommendations 16 General 16 Grading 17 Site Preparation 17 Select Grading 17 Cut/Fill Transition 17 Inported Fill 18 Rippability 18 Oversized Rock 18 Slope Construction 18 Surface Drainage 18 Si±idrains 19 Earthwork 19 Slope Stability 19 Foundations 19 General 19 Reinforcenent 20 Interior Concrete Slabs-on-Grade 20 Exterior Concrete Slabs-on-Grade 21 Special Lots 21 E:q)ansive Characteristics 21 Settlenent Characteristics 21 Earth Retaining Walls 22 Passive Pressure 22 Active Pressure 22 TABLE OF CGMTEMES (continued) Backfill Factor of Safety 22 Limitations 23 Review, Observation and Testing ''21 Uniformity of Conditions ' ^ ^ 23 Change in Scope 23 Tine Limitations ^ * . Professional Standard 24 Client's Responsibility ! " 24 Field Explorations .....[.....25 Laboratory Testing ...............[25 ATTBCHMEWES TABLES Table I Generalized Engineering Characteristics of Geologic Units, Paige 6 Table II The Maximum Bedrock Accelerations Table III Seismic Traverse Sunnary r Pages 9 FIGURE Figure 1 Site Vicinity Map, Follows Page 1 FLAXES Plate 1 Plot Plan Plate 2 Unified Soil Classification Chart Plates 3-9 Trench Logs Plate 10 Grain Size Distribution Plate 11 CcHtpaction Test Results Expansion Test Results Plate 12 Direct Shear Sunmary Plate 13 Oversize Rock Disposal Plate 14 Canyon Subdrain Detail Plate 15 Slope Stability Calculations Plate 16 Weakened Plane Joint Detail Plate 17 Retaining Wall Subdrain Detail Plates 18-20 Seismic Line Traverses Plates 21-23 Catepillar Rippability Charts APFEXCIX Reconmended Grading Specification and Special Provisions SOUTHERN CALIFORNIA SOIL AND TESTING, INC. 62B0 RIVERDALE ST. SAN OICGO, CALIF. 92120 • TELE 280-4321 • P.O. BOX 20627 SAN OIEGO, CALIF. 92120 67B ENTERPRISE ST. ESCONDIOO, CALIF. 92025 • TELE "7 a 6 • A S A A INTERIM REPORT OF CSXTTBCHNICAL INVESTIGflTION CALAVERA HEIQTTS VILLAGES W-X-Y TAMARACK AND COLLEGE BOULEVARD CARLSBAD, CALIFORNIA INTRODUCTION AND PRQJECT DESCRIPTION This report presents the results of our interim report of geotechnical investigation for Calavera Heights Subdivision, Villages W-X-Y, Tamarack and College Boulevard, in the City of Carlsbad, Califomia. The site location is illustrated on the following Figure Number 1. It is our understanding that the site will be developed to receive a residential si±)division with associated paved streets. It is anticipated that the stmctvires will be one and/or tvo stories high and of wood frane construction. Shallow foundations and conventional slab-on-grade floor systems are proposed. Grading will consist of cuts and fills up to approximately 40 feet and 35 feet deep, respectively. Cut and fill slopes up to approximately 35 feet high at a 2:1 (horizontal to vertical) are also anticipated. To assist with the preparation of this report, we were provided with a grading plan prepared by Hunsaker and Associates dated December 6, 1989. In addition ve revieved our "Supplemental Soil Investigation, Calavera Hills Subdivision," dated October 6, 1988, "Report of Geotechnical Investigation, Village Q and T, Calavera Hills Subdivision," dated January 10, 1984, and SOUTHERN CALIFORNIA SOIL AND TESTING. INC. I SOUTHIRM CALIPORNIA SOIL A TUTINQ,INC. CALAVERAS HEIGHTS-VILLAGE SOUTHIRM CALIPORNIA SOIL A TUTINQ,INC. BV: KAR/EM OATi: 5-15-90 SOUTHIRM CALIPORNIA SOIL A TUTINQ,INC. SCS&T 9021049 -May 15, 1990 Page 2 our 'Sunmary of Geotechnical Investigation, Lake Calavera Hills," dated August 6, 1984. The site configuration, topography and approxinate locations of the subsurface explorations are shown on Plate Number 1. PROJECT SCOPE This interim report is based on the review of the aforementioned preliminary report for the Calavera Hills Subdivision. A site specific report will be prepared at a later date when further field investigation and analysis of laboratory data has been completed. For the purpose of this report appropriate field investigation and laboratory test data was extracted from the previously nentioned report. More specifically, the intent of this study was to: a) Describe the subsurface conditions to the depths influenced by the proposed construction. b) The laboratory testing perforned in the referenced report was used to evaluate the pertinent engineering properties, including bearing capacities, expansive characteristics and settlement potential, of the anticipated materials v^ich will influence the developnent of the proposed subject site. c) Describe the rippability characteristics of the existing rock. d) Define the general geology at the site including possible geologic hazards v^ch could have an effect on the site developnent. e) Develop soil engineering criteria for site grading and provide recotmendations regarding the stability of proposed cut and fill slopes. f) Address potential construction difficulties and provide reconnendations conceming these problems. SCS&T 9021049 May 15, 1990 Page 3 g) Reconmend an appropriate foundation system for the type of structures anticipated and develop soil engineering design criteria for the reconmended foundation design. FINDINGS SHE ESESCKEPnON The subject site is an irregular shaped parcel of land, designated as Villages W, X and Y within the Calavera Heights developnent in Ccirlsbad, Califomia. The subject site covers approxinately one hunidred acres and is bounded on the south, east and north by vmdeveloped land and by residential housing and undeveloped land on the vest. Topoigraphically, the site is located in hilly terrain with well developed, large, drainage coiurses with steep-sided slopes. Elevations range from approximately 325 feet (MSL) at the central northem property boundary to 90 feet (MSL) at the eastem boundary. The inclinations of the natural slopes are generally on the order of 1.5 to 1, horizontal to vertical, or flatter. Drainage is acconplished via sheetflow and the veil developed drainage courses in southerly, easterly and northeasterly directions. Vegetation is conprised of sparse to very dense chaparral on the hillsides and dense native shrubs and small trees within the large drainage coiurses. Overhead power lines traverse the site in a southwest to northeast direction. The site is undeveloped, with the exception of the pover lines. (aWERAL GE3JU3SI AND SUBSURFACE OONDITIONS GBOLOGIC SEPETNG AND SOIL DESCRIPTION: The subject site is located near the boundary betveen the Foothills Physiographic Province and the Coastal Plains Physiographic Province of San Diego County and is underlain by materials of igneous and sedimentary origin and surficial residuum. The site is underlain by the basenent conplex rocks consisting of Jurassic-age netavolcanic rocks, Cretaceous-age granitic rocks, as veil as Tertiary-age Santiago Fonreition and Quatemary-age alluvium. A brief description of the materials on-site, in general decreasing order of age, is presented below. SCS&T 9021049 May 15, 1990 Page 4 1) BASEMENT CCMPLEX - JURASSIC METAVOLCANICS AMD CRETACEOUS GRANITICS {jBfr/Kgr): The oldest rocks exposed at the site are the Jurassic netavolcanic and associated hypabyssal rocks. The netavolcanic rocks are generally andesite or dacite in composition and the associated hypabyssal rocks are their porphyritic equivalents (ie: diorite porphyry to granodiorite porphyiry) . The fine grained hypabyssal rocks are considered to be about the same age as the netavolcanics and are consequently older than the other intrusive rocks found at the site. Both the metavolcanics and the associated hypabyssal rocks veather to dark, smooth hills or jagged, angular outcrops with a clayey, rocky topsoil. The metavolcanic and hypabyssal rocks are generally rippable with conventional earth-moving equipnent to depths of only a few feet. The other rocks in the basenent conplex are the granitic rocks of the Cretaceous Southem Califomia Batholith which have intmded the older rocks and are, to a large degree, mixed with them. The granitic rocks at the project site appear to be both tonalitic and granodioritic in conposition. The tonalitic rocks are usually dark gray, fine to medium grained rocks whereas the granodioritic rocks are usually yellowish brown to grayish brown, medium to coarse grained rocks. The weathering and rippability characteristics of the tonalitic rocks appear to be somev^at similar to those of the netavolcanic/hypabyssal rocks. The tonalitic rocks may be rippable to greater depths than the metavolcanic rocks but ripping may be difficult and tine consuming. In addition, it should be noted that the material generated from the tonalitic rocks will have the appearance of the metavolcanic rocks rather than that of good quality "decomposed granite". In contrast to the weathering characteristics of the metavolcanic/hypabyssal rock and the tonalitic rocks, the granodioritic rocks commonly weather to rounded outcrops or boulders in a matrix of grus ("decomposed granite"). The granodioritic rocks are variable in their excavation characteristics but conmonly contain areas which are rippable to SCS&T 9021049 May 15, 1990 Page 5 depths of several feet or several tens of feet, yet include localized areas of boulders or unweathered rock which are not rippable with conventional heavy equipment. The areas underlain by the respective rock types in the basenent complex are intermixed and are not differentiated on the accompanying geologic map. It should be noted that since the different rock types are mixed, the areas on the map where given a dual classification. The boundaries between the basenent rock types are very irregular, therefore they were not differentiated on Plate Number 1. 2) SANTIAGO FORMATICN (Es): The Eocene sediments at the project site are represented by the sandstones, siltstones, and claystones of the Santiago Formation. The Santiago Formation at the site appears to be characterized largely by the grayish white sandstones and siltstones with lesser amounts of the dark greenish brown claystone. A well-developed, clayey topsoil is present on nost of the Santiago Formation. 3) OLEER QUATERNARY (PLEISTOCENE) ALLUVIUM (Qoal): Older alluvial deposits consisting of grayish brown to yellowish brown and greenish brown, nedium dense, silty sands, clayey sands, and sandy silts vere encountered at the southeastem portion of the project site. These deposits range in thickness from only a few feet to in excess of ten feet. Smaller, un-mapped areas may be encountered at other scattered locations. 4) YDWK3ER QUATERNARY (HOLOCENE) ALLUVIUM (Qyal): Younger alluvial deposits consisting of unconsolidated, loose to medium dense deposits of clay, silt, sand, and gravel are present in the nodem drainage courses. These deposits range in thickness from less than a foot to over ten feet. Due to their ubiquitous occurrence, the younger alluvial deposits are not delineated on the geologic map except in the larger channels. SCS&T 9021049 May 15, 1990 Page 6 A relatively thin layer of loose topsoils and subsoils should be anticipated overlying the entire site. These deposits consist of varying nuxtures of silts, sands and clays. It is estimated that these deposits do not exceed 3.5 feet in combined thickness. Table I presents some of the pertinent engineering characteristics of the materials at the site. TABE£ I GENERALIZED ENGINEERING CHARACTERISTICS OF MAIN GBOLOGIC UNITS Unit Name and Symbol Antjunt of Slope Oversize Stability/ Rippability Material Erosion Compressibility Expansive Potential Granitic Rocks- Kgr (Granodiorite) Generally Rippable to + 15 Feet Low to Moderate Good Nominal Nominal Granitic Rocks- Kgr (Tonalite) Marginally Rippable to Nonrippable Moderate to High Good Nominal Nominal Metavolcanic and Hypatjyssal Rocks-Jmv Marginally Rippable to Nonrippable Moderate to High Good Nominal Nominal Scintiago Formation-Es (Mudstone) Rippable Nominal Generally Poor Low Moderate to High Santiago Formation-Es (Sandstone and Siltstone) Rippable Nominal Generally Good Low Low to Moderate Older Alluvium-Qoal Rippable Nominal Moderately Erodible Moderate to Hiqh Low to Hiqh SCS&T 9021049 May 15, 1990 Page 7 TBCICNIC SETTING: A few small, apparently inactive faults have been mapped previously vn.thin the vicinity of the site. No evidence of faulting was noted in our ejq)loratory trenches for the referenced reports but it is possible that futiure grading operations at the site may reveal some of these faults. Due to their status of activity and geometry, these snail faults should be only of minor consequence to the project. It should also be noted that several prominent fractures and joints which cu:e probably related, at least in part, to the strong tectonic forces that dominate the Southem Califomia region are present within the vicinity of the site. These features are usually near-vertical and strike in both a general northwesterly direction (subparallel to the regional structural trend) and in a general northeasterly direction (subperpendicular to the regional stiructural trend) . All cut slopes should be inspected by a qualified geologist to assess the presence of adverse jointing conditions in the final slopes. In addition, it should be recognized that much of Southem Califomia, is ageracterized by najor, active fault zones that could possibly affect the subject site. The nearest of these is the Elsinore Fault Zone, located approxinately 20 miles to the northeast. It should also be noted that the possible off-shore extension of the Rose Canyon Fault Zone is located approxinately eight miles vest of the site. The Rose Canyon Fault Zone conprises a series of northvest trending faults that could possibly be classified eis active based on recent geologic studies. It is anticipated that the Rose Canyon Fault will be classified as active in the neetr future. Recent seismic events along a small portion of the Rose Canyon Fault Zone have generated earthqueikes of 4.0 or less magnitude. Other active fault zones in the region that could possibly affect the site include the Coronado Banks and San Clemente Fault Zones to the vest, the Agua Bianca and San Miguel Fault Zones to the south, and the Elsinore and San Jacinto Fault Zones to the northeast. (SOLCGIC HAZARDS: The site is located in an area which is relatively free of potential geologic hazards. Hazards such as tsunamis, seiches, liquefaction, and landsliding should be considered negligible or nonexistent. SCS&T 9021049 May 15, 1990 Page 8 OROUNDSHAKING: One of the most likely geologic hazards to affect the site is groundshciking as a result of movement along one of the najor, active fault zones nentioned above. The maximum bedrock accelerations that vould be attributed to a naximum probable earthquake occurring along the nearest portion of selected fault zones that could affect the site are sunmarized in the following Table II. TABL£ II Fault Zone Maximum Probable Distance Bedrock Design Acceleration Acceleration Rose Canyon 8 miles 6.5 nagnitude 0 36 g 0. 23 g Elsinore 20 miles 7.3 nagnitude 0 25 g 0. 17 g Coronado Banks 24 miles 7.0 nagnitude 0 18 g 0. 12 g San Jacinto 43 miles 7.8 magnitude 0 14 g 0. 10 g Earthquakes on the Rose Canyon Fault Zone are expected to be relatively minor. Major seismic events are likely to be the result of movement along the Coronado Banks, San Jacinto, or Elsinore Fault Zones. Experience has shown that structures that are constructed in accordance with the Uniform Building Code are fairly resistant to seismic related hazards. It is, therefore, our opinion that structural damage is unlikely if such buildings are designed and constructed in accordance with the minimum standards of the most recent edition of the Uniform Building Code. SEISMIC SURVEY AND RIPPABILITY CHAR^OERISTICS GENERAL: The results of our seismic survey and exploratory trenches performed for the referenced reports indicate that blasting vrLll be required to obtain proposed cuts. In addition, isolated boulders are anticipated within cut areas that may require special handling during grading operations. A sunmary of each seismic traverse is presented in Table III SCS&T 9021049 T'lay 15, 1990 Page 9 below, and Plates Nuniber 18 through 20. Our interpretation is based on the rippability characteristics of granitic and netavolcanic rock as described in Pages 12 through 15. TABLE III Seismic Traverse No. S73-14 Proposed Cut: 48 Feet Geologic Unit: Metavolcanic Interpretation: 0'-15' Nonrippable Seismic Traverse No. SW-10 Proposed Cut: Geologic Unit: Interpretation: 50 Feet Metavolcanic 0'- 3' Rippable 3'-17' Rippable with Hardrock Floaters 17'-30' Nonrippable Seismic Ttaverse No. SW-IOR Proposed Cut: Geologic Unit: Interpretation: 50 Feet Metavolcanic 0'- 3' Rippable 3'-17' Rippable with Hardrock Floaters 17'-30' Nonrippable Seismic Traverse No. SW-11 Proposed Cut; None Geologic Unit: Metavolcanic Interpretation: 0'- 6' Rippable 6'-2 7' Nonrippable Seismic Traverse No. SW-llR Proposed Cut: None Geologic Unit: Metavolcanic Interpretation: 0'- 6' Rippable 6'-27' Nonrippable SCS&T 9021049 May 15, 1990 Page 10 TABE£ III (continued) Seismic Traverse No. SW-12 Proposed Cut: Geologic Unit: Interpretation: 29 Feet rfetavolcanic 0'- 6' Rippable 6'-21' Marginally Rippable with Hardrock Floaters + 21' Nonrippable Seismic Traverse No. SW-12R Proposed Cut: 29 Feet Geologic Unit: Metavolcanic Interpretation: 0'- 5' Rippable 5'- 26' Rippable with Hardrock Floaters + 26' Nonrippable Seismic Traverse No. SW-13 Proposed Cut: Geologic Unit: Interpretation: 13 Feet Metavolcanic 0'- 4' Rippable 4'-15' Rippable with Hardrock Floaters + 15' Nonrippable Seismic Traverse No. SW-14 Proposed Cut: 38 Feet Geologic Unit: Metavolcanic Interpretation: 0'- 4' Rippable 4'-21' Rippable with Hardrock Floaters + 21' Nonrippable Seismic Traverse No. SW-14R Proposed Cut: 38 Feet Geologic Unit: Metavolcanic Interpretation: 0'- 3' Rippable 3'-14' Rippable with Hardrock Floaters 14' -30' Marginally Rippable with Hardrock Floaters SCS&T 9021049 May 15, 1990 Page 11 TABLE III (continued) Seismic Traverse No. SX-15 Proposed Cut: Geologic Unit: Interpretation: Unknown rfetavolcanic 0'- 6' Ripjpable 6'-15' Rippable with Hardrock Floaters + 15' Nonrippable Seismic Traverse No. SX-15R Proposed Cut: Unknown Geologic Unit: Metavolcanic Interpretation: O'-ll' Rippable + 11' Nonrippable Seismic Traverse No. SZl-16 Proposed Cut: Geologic Unit: Interpretation: None Granitic 0'-16' 16'-27' + 27' Rippable Rippable with Hardrock Floaters Nonrippable Seismic Traverse No. SZ1-16R Proposed Cut: None Geologic Unit: Metavolcanic/Granitic Interpretation: 0'-20' Rippable vd.th Hardrock Floaters + 20' Nonrippable Seismic Traverse No. SZ2-17 Proposed Cut: Unknown Geologic Unit: Metavolcanic/Granitic Interpretation: 0'- 5' Rippable + 5' Nonrippable SCS&T 9021049 May 15, 1990 Page 12 TABE£ III (continued) Seismic Traverse No. SZ2-17R Proposed Cut: UnJaiown Geologic Unit: Metavolcanic/Granitic Interpretation: 0'-20' Rippable with Hardrock Floaters + 20' Nonrippable In general, our seismic survey indicated that areas underlain by granitic rock present rippable naterial to depths ranging up to approximately 27 feet, with nonripjpable naterial below this depth. In areas underlain by netavolcanic and associated hypabyssal rock, nonrippable naterials appear to be encountered at depths of approxinately 0 feet to 21 feet. In adciition, a variable zone of marginally rippable rock usually exists between the rippable and nonrippable rock. The generation of fine naterial during blasting and mining operations is essential due to the characteristics of the on-site rock material. Therefore, "pre-shooting" of nonrippable material before removing the overlying soils and rippable rock is suggested. This procedure often helps to generate more fine naterial and to facilitate the mixing of soil and rock to be used as fill. RIPPABILITy CHARACTERISTIC OF G3»N0DICeiTIC ROCK RIFPABC£ OCNDinON (0-4,500 FT./SBC.): This velocity range indicates rippable materials which may consist of decomposed granitic rock possessing random heirdrcock floaters. These naterials will break down into slightly silty, veil graded sand, v^ereas the floaters vrLll require disposal in an area of nonstructural fill. Some areas containing numerous hardrock floaters nay present utility trench problems. Further, large floaters exposed at or near finish grade nay present additional problems of removal and disposal. SCS&T 9021049 May 15, 1990 Page 13 Materials within the velocity range of from 3,500 to 4,000 fps are rippable with difficulty by backhoes and other light trenching equipanent. MARGINALLY RIFPAHLE CONDITION (4,500 FT./SBC--5,500 Pr./SBC.): This range is rippable with effort by a D-9 in only slightly weathered granitics. This velocity range nay also include numerous floaters with the possibility of extensive areas of fractured granitics. Excavations may produce naterial that will partially break down into a coarse, slightly silty to clean sand, but containing a high percentage of + 1/4" material. Less fractured or weathered naterials may be found in this velocity range that would require blasting to facilitate removal. Materials within this velocity range are beyond the capability of backhoes and lighter trenching equipment. Difficulty of excavation would also be realized by gradalls and other heavy trenching equipment. NONRIPPABI£ CCMDmON (5,500 FT./SEC. & O^EMER): This velocity range includes nonrippc±)le material consisting primarily of fractured granitics at lower velocities with increasing hardness at higher velocities. In its natural state, it is not desirable for building pad subgrade. Blasting will produce oversize naterial requiring disposal in areas of nonstmctural fill. This upper limit has been based on the Rippability Chart shown on Plates Nunter 18 through 20 utilized for this report. However, as noted in the Caterpillar Chart on Plates Number 21 through 23, this upper limit of rippability nay scjietimes be increased to 7,000 to 8,000 fps material using the D-9 mounted #9 Series D Ripper. RTPPARTT.TW GHARACTERISTICS OF HE13VV0SX2NICS AND ASSOCIATED HYPABYSSAL ROCKS AND TONALITIC BOCKS RIPPABLE CHrornCN (0-4,soo FT./SBC.): This velocity range indicates rippable naterials v^ich may vary from deconposed netavolcanics at SCS&T 9021049 May 15, 1990 Page 14 lover velocities to only slightly decomposed, fractured rock at the higher velocities. Although rippable, naterials may be produced by excavation that will not be useable in structural fills due to a lack of fines. Experience has shown that naterial within the range of 4,000 to 4,500 fps most often consists of severely to moderately fractured angular rock with little or no fines and sizeable quantities of + 1/4" material. For velocities between 3,500 to 4,500 fps, rippability will be difficult for backhoes and light trenching equipment. MARGINALLY RIPPABLE CONDITION (4,500-5,500 FT./SBC.): Excavations in this velocity range would be extrenely time consuming and vould produce fractured rxock with little or no fines. The higher velocities could require blasting. Trenching equipnnent vould not function. NONRIPPABLE CXIDITION (5,500 FT./SBC. & C3^EATER): This velocity range may include moderately to slightly fractured rock which vould require blasting for removal. Material produced would consist of a high percentage of oversize and angular rock. Rippability of netavolcanics may be acconplished for higher velocities using the Caterpillar D-9 with the #9 D Series Ripper. Due to the fractured nature of sone metavolcanics, ripping might be accomplished in as high as 8,000 fps material. SEISMIC TRAVERSE LIMITKTICINS The results of the seismic survey for this investigation reflect rippability conditions only for the areas of the traverses. Bovever, the conditions of the various soil-rock units appear to be similar for the renainder of the site and may be assumed to possess similar characteristics. SCS&T 9021049 May 15, 1990 Page 15 Our reporting is presently limited in that refraction seismic surveys do not allow for prediction of a percentage of expectable oversize or hardrock floaters. Subsurface variations in the degree of weathered rock to fractured rock are not accurately predictable. The seismic refraction nethod requires that naterials become increasingly dense with depth. In areas vAiere denser, higher velocity naterials are underlain by lover velocity naterials, the lover velocity materials would not be indicated by our survey. All of the velocities used as upper limits for rippability are subject to fluctuation depjending upon such local variations in rock conditions as: a) Fractures, Faults and Planes of Weakness of Any Kind b) Weathering and Degree of Decomposition c) Brittleness and Crystalline Nature d) Grain Size Further, the range of rippability using Caterpillar equipment may be increased using different equipment. However, it should be noted that ripping of higher velocity naterials nay become totally dependent on the tine available and the economics of the project. Ripjping of higher velocity materials can be achieved but it may become economically infeasible. GROUNDWATER: No groundwater was encountered during our subsurface explorations for the referenced reports. Even though no najor grounciwater problems are anticipated either during or after construction of the proposed development, seasonal groundwater from precipitation runoff may be encountered within the larger drainage swales during grading for the developnent. It is suggested that canyon subdrains be installed within drainage swales vhich are to receive fill. It should be realized that groundwater problems nay occur after development of a site even vtere none vere present before development. These are usually minor phenomena and are often the result of an alteration of the permeability characteristics of the SCS&T 9021049 May 15, 1990 Page 16 soil, an alteration in drainage pattems and an increase in irrigation water. Based on the permeability characteristics of the soil and the anticipated usage of the development, it is our opinion that any seepage problems which may occur will te minor in extent. It is further our opinion that these problems can te most effectively corrected on an individual basis if and when they develop. CONCLUSIONS AND RECOMMENDATIONS GENERAL In general, no geotechnical conditions v^re encountered which vould preclude the development of the site as tentatively planned, provided the recommendations presented herein are followed. The main geotechnical condition that will affect the proposed site developnent include hard granitic, metavolcanic, and hypabyssal rock, v^ch will require heavy ripping and blasting in order to make the proposed excavations. It is anticipated that the material generated from the cuts of the granitic, netavolcanic and hypabyssal rock will contain relatively low amounts of fine soils and large amounts of oversized naterial. Since rock fills require a percentage of fine soil, mining of the site, inporting of fine naterials or exporting excess rock may te necessary. Existing loose surficial deposits such as topsoils, subsoils, younger alluvium, and any weathered formational materials encountered are considered unsuitable for the support of settlenent sensitive inprovenents, and will require removal and/or replacenent as conpacted fill. Expansive soils vere also present within the subject area. Where possible, select grading is reconmended to keep nondetrinentally expansive soils within four feet from finish pad grade. In areas where this is not feasible, special foundation consideration will te necessary. However, it is anticipated that only minor amounts of expansive soils will te encountered. SCS&T 9021049 May 15, 1990 Page 17 O^ING SITE PREPARATICN: Site preparation should begin with the removal of any existing vegetation and deleterious natter from proposed improvement areas. Removal of trees should include their root system. Any existing loose surficial deposits such as topsoils, subsoils, younger alluvium and any weathered formational naterials, in areas to te graded should te removed to firm natural ground. The extent of the topsoils and subsoils will be approxinately one to three and one half feet. Firm natural ground is defined as soil having an in-place density of at least 90 percent. Soils exposed in the tottom of excavations should te scarified to a depth of 12 inches, moisture conditioned and reconpacted to at least 90 percent as determined in accordance with ASTM D 1557-78, Method A or C. The minimum horizontal limits of removal should include at least five feet beyond the perimeter of the structures, and all areas to receive fill and/or settlement-sensitive inprovenents. SEEBCT ORADING: Expansive soils should not te allowed within four feet from finish pad grade. In addition, expansive soils should not te placed within a distance from the face of fill slopes equal to ten feet or half the slope height, v^chever is more. Select material should consist of granular soil with an expansion index of less than 50. It is reconmended that select soils have relatively low pemeability characteristics. In areas undercut for select grading purposes, the tottom of the excavation should te sloped at a niinimum of three percent away from the center of the structure. Mininum lateral extent of select grading should te five feet away from the perimeter of settlement-sensitive inprovements. COT/FHiL TRANSITICN: It is anticipated that a transition line tetween cut and fill soils nay run through some of the proposed building pads. Due to the different settlement characteristics of cut and fill soils, constmction of a stmcture partially on cut and partially on fill is not reconmended. Based on this, ve reconmend that the cut portion of the building pads te undercut to a depth of at least three feet telow finish grade, and the SCS&T 9021049 May 15, 1990 Page 18 materials so excavated replaced as uniformly conpacted fill. The minimum horizontal limits of these reconmendations should extend at least five feet outside of the proposed inprovenents. IMPCmED FILL: All fill soil inported to the site should te granular and should have an expansion index of less that 50. Further, inport fill should te free of rock and lunps of soil larger than six inches in dianeter and should te at least 40 percent finer than 1/4-inch. Any soil to te inported should te approved by a representative of this office prior to inporting. RTPPABILrrr: It is anticipated that the proposed cuts will require heavy ripping and blasting. Plates Numter 18 through 20 contain the results of our seismic traverses. The results are sunmarized within this report. This condition will be further evaluated during the preparation of the geotechnical investigation report. Additional seismic traverses will te perfomed in eireas where deep cuts are proposed. OVERSIZED ROCK: Oversized rock is defined as naterial exceeding six inches in naximum dimension. It is anticipated that oversized naterial will te generated from proposed cuts. Oversized naterial nay te placed in stmctural fills as described in Plate Numter 13. SLOPE CONSTRUCTION: The face of all fill slopes should te conpacted by backrolling with a sheepsfoot conpactor at vertical intervals no greater than four feet and should te track walked when conpleted. Select grading should te perforned to limit expansive soils within ten feet from face of fill slope or one half the slope height, whichever is greater. Reconmendations contained within this report reflect a select grading condition. All cut slopes should te oteerved by our engineering geologist to verify steible geologic conditions. Should any unstable conditions te found, mitigating measures could te required. SURFACE DRAINAGE: It is reconmended that all siurface drainage te directed away from the stmctures and the top of slopes. Ponding of water should not te alloved adjacent to the foundations. SCS&T 9021049 May 15, 1990 Page 19 SUBDRAINS: A subdrain should te installed in canyon areas to receive fill in excess of ten feet. A subdrain detail is provided in Plate Numter 14. EARmwORK: All earthwork and grading contemplated for site preparation should te accomplished in accordance with the attached Reconmended Grading Specifications and Special Provisions. All special site preparation reconmendations presented in the sections above will supersede those in the Standard Reconnended Grading Specifications. All embankments, stmctural fill and fill should te conpacted to at least 90% relative conpaction at or slightly over optimum moisture content. Utility trench backfill within five feet of the proposed stmctures and teneath asphalt pavements should te compacted to minimum of 90% of its naximum dry density. The upper tvelve inches of subgrade teneath paved areas should te conpacted to 95% of its maximum dry density. This compaction should te obtained by the paving contractor just prior to placing the aggregate base naterial and should not te part of the mass grading requirements. The naximum dry density of each soil typ>e should te determined in accordance with ASTM Test Method D-1557-78, ffethod A or C SLOPE STABIUTY Proposed cut and fill slopes should te constructed at a 2:1 (horizontal to vertical) or flatter inclination. It is estimated that cut and fill slopes will extend to a naximum height of atout 35 feet. It is our opinion that said slopes will possess an adequate factor of safety with respect to deep seated rotational failure and surficial failure (see Plate Nunfcer 15). Tte engineering geologist should observe all cut slopes during grading to ascertain that no adverse conditions are encountered. (3NERAL: If the lots are capped with nondetrinentally expansive soils, conventional shallow foundations nay te utilized for the support of the proposed stmctures. The footings should have a minimum depth of 12 inches SCS&T 9021049 May 15, 1990 Page 20 and 18 inches telow lowest adjacent finish pad grade for one-and-tvo-story constmction, respectively. A minimum width of 12 inches and 18 inches is reconmended for continuous and isolated footings, respectively. A tearing capacity of 2000 psf may be assumed for said footings. This bearing capacity nay te increased by one-third when considering wind and/or seismic forces. Footings located adjacent to or within slopes should te extended to a depth such that a minimum distance of six feet and seven feet exist tetween the footing and the face of cut slopes or fill slopes, respectively. Retaining walls in similar conditions should te individually revieved by this office. If it is found to be unfeasible to cap the lots with nondetrinentally expansive soils as reconnended, special foundation and slab design will te necessary. This generally consists of deepened and more heavily reinforced footings, thicker, more heavily reinforced slabs. Recomrendations for expansive soil conditions will te provided after site grading when the expansion index and depth of the prevailing foundation soils are known. REINEOOMENT: Both exterior and interior continuous footings should te reinforced with at least one No. 4 bar positioned near the tottom of the footing and one No. 4 bar positioned near the top of the footing. This reinforcenent is tesed on soil characteristics and is not intended to te in lieu of reinforcenent necessary to satisfy stmctural considerations. If expansive soils exist within four feet of finish grade, additional reinforcing will te necessary. INTERIOR CONCRETE ON-GRADE SLABS: If the pads are capped with nondetrimentally expansive soils, concrete on-grade slabs should have a thickness of four inches and te reinforced with at least No. 3 reinforcing bars placed at 36 inches on center each way. Slab reinforcenent should te placed near the middle of the slab. As an altemative, the slab reinforcing may consist of 6"x6"-W1.4jrt*1.4 (6"x6"-10/10) welded wire nesh. However, it should te realized that it is difficult to maintain the proper position of wire nesh during placement of the concrete. A four-inch-thick layer of clean, coarse sand or crushed rock should te placed under the slab. This SCS&T 9021049 -May 15, 1990 Page 21 layer should consist of material having 100 percent passing the one-half-inch screen; no more than ten percent passing sieve #100 and no more than five percent passing sieve #200. Where moisture-sensitive floor coverings are planned, the sand or rock should te overlain by a visqueen moisture barrier and a tvo-inch-thick layer of sand or silty sand should te provided above the visqueen to allow proper concrete curing. EXTERIC» SUfflS-CN-GRAIK: For nonexpansive soil conditions, exterior slabs should have a niinimum thickness of four inches. Walks or slate five feet in width should te reinforced with 6"x6"-W1.4xW1.4 (6"x6"-10/10) welded wire mesh and provided with weakened plane joints. Any slabs tetveen five and ten feet should te provided with longitudinal weakened plane joints at the center lines. Slabs exceeding ten feet in width should te provided with a weakened plane joint located three feet inside the exterior perineter as indicated on attached Plate Number 16. Both traverse and longitudinal weakened plane joints should te constmcted as detailed in Plate Numter 16. Exterior slate adjacent to doors and garage openings should te connected to the footings by dowels consisting of No. 3 reinforcing bars placed at 24-inch intervals extending 18 inches into the footing and the slab. SPECLAL LOTS: Special lots are defined as lots underlain by fill with differential thickness in excess of ten feet. The following increased foundation reconnendations should te utilized for said lots. Footings should te reinforced with two No. 4 bars positioned near the tottom of the footing and two No. 4 bars positioned near the top of the footing. Concrete on grade slate should te reinforced with at least No. 3 reinforcing bars placed at 18 inches on center each way. Lots with fill differentials in excess of thirty feet should te evaluated on an individual tesis. EXPANSIVE CHARACTERISTICS: Metavolcanic rock generally veathers to a clayey suteoil, and its presence within four feet of finish pad grade will require special site preparation and/or foundation consideration. SETTLniEWr OBfflACIERISnCS: Tte anticipated total and/or differential settlements for the proposed stmctures may te considered to te vdthin SCS&T 9021049 May 15, 1990 Page 22 tolerable limits provided the reconmendations presented in this report are followed. It should te recognized that minor hairline cracks on concrete due to shrinkage of constmction naterials or redistribution of stresses are nomal and may te anticipated. EAKIH RETAINING WALLS PASSIVE PRESSURE: The passive pressure for the prevailing soil conditions may te considered to te 450 pounds per square foot per foot of depth up to a maximum of 2000 psf. This pressure nay te increased one-third for seismic loading. The coefficient of friction for concrete to soil nay te assumed to te 0.35 for the resistance to lateral movenent. When contoining frictional and passive resistance, the fomer should te reduced by one-third. The upjper 12 inches of exterior retaining wall footings should not te included in passive pressure calculations when landscaping abuts the tottom of the wall. ACTIVE PRESSURE: The active soil pressure for the design of unrestrained earth retaining stmctures with level backfills may be assumed to be equivalent to the pressure of a fluid veighing 35 pounds per cubic foot. For 2:1 (horizontal to vertical) sloping teckfills, 14 pcf should te added to the preceding values. These pressures do not consider any surcharge. If any are anticipated, this office should te contacted for the necessary increase in soil pressure. This value assumes a drained backfill condition. Waterproofing details should be provided by the project architect. A subdraiji detail is provided on the attached Plate Numter 17. BftCKFDLL: All teckfill soils should te conpacted to at least 90% relative compaction. Expansive or clayey soils should not te used for teckfill naterial. The vall should not te teckf illed until the masonry has reached an adequate strength. FNJTOR OF SAFETTY: The above values, with the exception of the allowable soil tearing pressure, do not include a factor of safety. Appropriate factors of safety should te incorporated into the design to prevent the walls from overtuming and sliding. SCS&T 9021049 May 15, 1990 Page 23 LIMITATIONS REVIEW, OBSERVKTIGN AND TESTING The reconnendations presented in this report are contingent upon our review of final plans and specifications. Such plans and specifications should te made available to tte geotechnical engineer and engineering geologist so that they may review and verify their conpliance with this report and with Chapter 70 of the Uniform Building Code. It is reconnended that Southem Califomia Soil & Testing, Inc. te retained to provide continuous soil engineering services during the earthwork operations. This is to verify compliance with the design concepts, specifications or reconnendations and to allow design changes in the event that subsurface conditions differ from those anticipated prior to start of constmction. UNIFUKMITY OF COMDITiatB The reconnendations and opinions expressed in this report reflect our test estimate of the project requirements based on an evaluation of the subsurface soil conditions encountered at the subsurface exploration locations and on the assunption that the soil conditions do not deviate appreciably from those encountered. It should be recognized that the performance of the foundations and/or cut and fill slopes nay te influenced by undisclosed or unforeseen variations in the soil conditions that nay occur in the intermediate and unexplored areas. Any unusual conditions not covered in this report that nay te encountered during site developnent should te brought to the attention of the geotechnical engineer so that he nay nake modifications if necessary. CHANGE IN SCOPE This office should be advised of any changes in the project scopje or proposed site grading so that ve may determine if the recommendations contained herein are appropriate. This should te verified in writing or modified by a written addendum. SCS&T 9021049 May 15, 1990 Page 24 TIME LIMITATIONS The findings of this report are valid as of this date. Changes in the condition of a property can, however, occur with the passage of time, v^iether they te due to natural processes or the work of man on this or adjacent properties. In addition, changes in the Standards-of-Practice and/or Govemnent Codes nay occur. EXie to such changes, the findings of this report nay te invalidated wholly or in part by changes beyond our control. Therefore, this report should not te relied upon after a period of tvro years without a review by us verifying the suitability of the conclusions and reconmendations. PROFESSICWAL SiaMlARD In tte perfomance of our professional services, we conply with that level of care and skill ordinarily exercised by memters of our profession currently practicing under similar conditions and in the same locality. Tte client recognizes that suteurface conditions nay vary from those encountered at the locations wtere oiur trenches, surveys, and explorations are nade, and that our data, interpretations, and reconnendations are tesed solely on the information obtained by us. We will be responsible for those data, interpretations, and reconnendations, but shall not te responsible for the interpretations by others of the information developed. Our services consist of professional consultation and observation only, and no warranty of any kind whatsoever, express or implied, is made or intended in connection vdth tte vork perfomed or to te performed by us, or by our proposal for consulting or other services, or by our fumishing of oral or written reports or findings. CLIENT'S RESPONSIBILITY It is the responsibility of Lyon Communities Incorporated, or their representatives to ensure that the infomation and reconnendations contained herein are brought to the attention of the stmctural engineer and architect SCS&T 9021049 May 15, 1990 Page 25 for the project and incorporated into the project's plans and specifications. It is further their responsibility to take the necessary measures to insure that the contractor and his suteontractors carry out such reconmendations during constmction. FIELD EXPLORATIONS Three subsurface trench explorations vere made at the locations indicated on tte attached Plate Numter 1 on Decemter 21, 1982, and three on July 7, 1983, adjacent to or within the subject site (see Plates Numter 3 through 6). In addition, Plates Nunter 7 through 9 from the referenced reports contain additional trench excavations nade in Decenter 15, 1982, of similar soils within the subject subdivision. These explorations consisted of trenches dug by the neans of a teckhoe. One seisndc traverse was perfomied on .^ril 14, 1973 and eight were performed on January 11, 1983. The field work was conducted under the observation of our engineering geology personnel. Tte results are shown on Plates Numter 18 through 20. The soils are described in accordance with the Unified Soils Classification System as illustrated on the attached sinplified chart on Plate 2. In addition, a verbal textural description, the wet color, the apparent moisture and the density or consistency are provided. The density of granular soils is given as either very loose, loose, nedium dense, dense or very dense. The consistency of silts or clays is given as either very soft, soft, medium stiff, stiff, very stiff, or hard. LABORATORY TESTING Latoratory tests vere performed in accordance with the generally accepted Anerican Society for Testing and Materials (ASTM) test methods or suggested procedures. A brief description of tte tests performed is presented telow: a) CLASSIFICATICN: Field classifications vere verified in the laboratory by visual examination. Tte final soil classifications are in accordance with the Unified Soil Classification System. SCS&T 9021049 May 15, 1990 Page 26 b) MDISTORE-CSliBITy: In-place moisture contents and dry densities vere determined for representative soil samples. This infomation was an aid to classification and permitted recognition of variations in naterial consistency with depth. The dry unit weight is determined in pounds per cubic foot, and the in-place moisture content is determined as a percentage of the soil's dry weight. The results are sunmarized in the trench logs. c) GRAIN SIZE DISTRIBUTION: The grain size distribution was determined for representative sanples of the native soils in accordance with ASTM D422. The results of these tests are presented on Plate Numter 10. d) COMPACTION TEST: The maximum dry density and optimum noisture content of typical soils vere determined in the latoratory in accordance with ASTM Standard Test D-1557-78, Method A. The results of these tests are presented on the attached Plate Nirater 11. e) EXPANSION TEST: The expansive potential of clayey soils was determined in accordance with the following test procedure and the results of these tests appear on Plate Numter 11. Allow the trinned, undisturbed or remolded sample to air dry to a constant moisture content, at a temperature of 100 degrees F. Place the dried sample in the consolidometer and allow to conpress under a load of 150 psf. Allow moisture to contact the sanple and neasure its expansion from an air dried to saturated condition. f) DIRECT SHEAR TESTS: Direct shear tests vere performed to determine the failure envelope based on yield stear strength. The shear box was designed to accommodate a sample having a SCS&T 9021049 May 15, 1990 Page 27 diameter of 2.375 inches or 2.50 inches and a height of 1.0 inch. Samples vere tested at different vertical loads and a saturated moisture content. The shear stress was applied at a constant rate of strain of approxinately 0.05 inches per minute. The average shear strength values for granitic and metavolcanic rock are presented on attached Plate Numter 12. SUBSURFACE EXPLORATION LEGEND UNIFIED SOIL CLASSIFICATION CHART SOIL DESCRIPTION GROUP SYMBOL TYPICAL NAMES I. COARSE GRAINED, more than half of material is larger than No. 200 sieve size. G'MV^IS CLEAN GRAVELS More tnan half of coarse fraction is larger than No. 4 sieve size but smaller than 3" SANDS I More than half of coarse fraction is smaller than No. 4 sieve size. GRAVELS WITH FINES (Appreciable amount of fines) CLEAN SANDS SANDS WITH FINES (Appreciable amount of fines) GW GP GM GC SW SP SM SC II. FINE GRAINED, more than half of material is smaller than No. 200 sieve sTze^ SILTS ANO CLAYS Liquid Limit less than 50 ML CL SILTS ANO CLAYS Liquid Limit greater than 50 CH OH HIGHLY ORGANIC SOILS PT Well graded gravels, sravel- sand mixtures, little'or no fines. Poorly graoed gravels, gravel sand mixtures, little or no fines. Silty gravels, poorly graded gravel-sand-silt mixtures. Clayey gravels, poorly graded gravel-sand, clay mixtures. Wen graded sand, gravelly sands, little or no fines. Poorly graded sands, gravellv sands, little or no fines. Silty sands, poorly graded sand and silty mixtures. Clayey sands, poorly graded sand and clay mixtures. Inorganic silts and very fine sands, roclc flour, sandy silt or clayey-silt-sand mixtures with sliaht plas- ticity. Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. Organic silts and oraanic silty clays or low plasticity. Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts. Inorganic clays of high plasticity, fat clays. Organic clays of medium to high plasticity. Peat and ot/ier highly organic soils. US - Water level at time of excavation or as indicated Undisturbed, driven ring sample or tube sample CK BG SP Undisturbed chunk sample Bulk sample Standard penetration sample y^SOUTHBRM CALIFORNIA ^^^^ SOIL A TBSTING, INC. CALAVERA HEIGHTS-VILLAGF U-Y.v 1 BY: KAR/EM DATE: 5-03-90 1 JOB NUMBER: 9021049 Plate No. 2 | Class TRENCH :;o. :T-50 .'escriPtion I SM Gray-brown, Moist, Dense co Verv Dense, Silty Sand (Decomposed Granite) Trench Ended ac 4 Feet SOUTHERIM CALIFORNIA SOIL & TESTINQ , INC. •••a nivanoALH •TRBIT •AN OIBOia, CAkl^OHNIA ••IBO I CALAVERA HEIGHTS-VILLAGE W-X-Y BY CRB JOB NO. 9021049 DATE 12-21-82 Piatt; Mo. 3 ~1 / V 10 Jl Sll/ sc / CL Sroxvn - r.ed-brouTi, Cla-.-ev .Silev .-'.ma ...rise. ..eaium Jense, "'3Cli} Vellov;-broOT, .".ea-brown. J i"av-b return. lloisc, ;iediun jense. Clavev Silcv .Sand, Porous I Older .\lluvium') Sanay Clav/Clavev Sa na . rencn :.ndea ac 10 Feet -13. 8.0 10/ .3 15.5 SOUTHERN CALIFORNIA SOIL & TESTING , INC. •AN Diaao, CAt-i^oHNiA ••iao BY CALAVERA HEIGHTS-VILLAGE W-X-Y :RB JOB NO. 9021049 OATE 12-21-82 Plate I'o. 4 A s:;/ Lss escnmcp. r ec-orown. ;'cisc. !'.3dlur. j^nse. ~ layev S..lr" S.inc I ." .•Dsoii) Lej.icw ana urav-r^ro^^oi. ..jisc. _ense co Ver\- Dense, Silcy Sand i Cec;otr.Dosed Granite) Trench Ended ac J Feet • /^\. SOUTHERN CALIFORNIA ^^rN BOIL & TESTING , INC. HI BAN oiaso, CAkifionNiA aanao CALAVERA HEIGHTS-VILLAGE W-X-Y 1 BY CRB 12-21-82 1 JOB NO. ~ 9021049 Plate No. 5 LU a > a. < 10 z o < o 10 < o TRENCH NUMBER TX-77 ELEVATIO N DESCRIPTION = (- < W Q. — Q. O < z > z z UJ UJ oc ^ ; i2 a- to * o u > (0 z UJ a E O w z _ UJ >- ° 1 >• oc o UJ c 3 I- CA O Ul O u UJ o t- o < < -< a UJ 2 « o o GM BROWN SANDY GRAVEL (TOPSOIL) HUMID/ MOIST MEDIUM DENSE GM GRAY BROWN SANDY GRAVEL (METAVOLCANIC ROCK) HUMID VERY DENSE REFUSAL AT 2.5' TX-78 CL BROWN SILTY CLAY (TOPSOIL) MOIST STIFF GM GRAY BROWN SANDY GRAVEL (METAVOLCANIC ROCK) HUMID VERY DENSE REFUSAL AT 3' TRENCH NUMBER X-79 CL BROWN SILTY CLAY (TOPSOIL) MOIST STIFF GM GRAY BROWN SANDY GRAVEL (METAVOLCANIC ROCK) HUMID VERY DENSE REFUSAL AT 3' SOUTHERN CALIFORNIA SOIL ATESTINGJNC. SUBSURFACE EXPLORATION LOG LOGGED BY: DATE LOGGED: 7-18-83 JOB NUMBER: 9021049 Plate No. 6 I I f i T R ENCH NUMBER -I < I I 5 u. ; E_EVAT;- r I Ul 2 I < I < I • EEC." IPTIC.M < w Q. — X O < Z e «< a a < 2 C OJ (A O o -J V) z _ UJ — Q O X a UJ X UJ O z z UJ h- Z o o SM/Sq RED BROWN. CLAYEY SILTY SAND (TOPSOIL) UJ > -J UJ K Z o o < a. Z o u RED, BROWN. GRAY, SANDY CLAY (WEATHERED DECOMPOSED GRANITE) YELLOW BROWN, SILTY GRAVELY SAND (DECOMPOSED GRANITE) MOIST TO WET WET MOIST MEDIUM DENSE MEDIUM STIFF DENSE TO VERY DENSE REFUSAL AT 3 TRENCH NUMBER Tg-2 I I I r BG CK SM/SL ML BROWN CLAYEY SILTY SAND (TOPSOIL) MOIST GREEN BROWN, SANDY SILT MOIST MEDIUM DENSE STIFF 4 — :SM/ML I c I I I I I t BG YELLOW. RED, BROWN, SILTY MOIST SAND (WEATHERED DECOMPOSED GRANITE) MEDIUM DENSE SM '6- YELLOW BROWN, SILTY SAND (DECOMPOSED GRANITE) MOIST MEDIUM DENSE TO DENSE 121 .9 12.1 VERY DENSE TRENCH ENDED AT 8' SOUTHERN CALIFORNIA SOIL ATESTING,INC. SUBSURFACE EXPLORATION LOG LOGGED BY: DATE LOGGED: a. UJ 0. f ; TR ENCH NUMBER 2 I < I 'Jl < 5 I — < tn Q. — a. O < Z Z 2 - UJ UJ cn < a. z o u UJ o CO z _ UJ ~ ° 1 > • o z z Ui 1-z o z > — — I— < < Q. UJ 3 = 5 u BAGSM/Sq RED BROWN. CLAYEY SILTY , SAND (TOPSOIL) MOIST MEDIUM DENSE SM CK 6. 7. 8 - CK ' YELLOW BROWN, SILTY SAND (DECOMPOSED GRANITE) MOIST DENSE TO VERY DENSE 118.2 10.8 0^ TRENCH ENDED AT 8' TRENCH NUMBER '3-7 CK SM ' RED BROWN, (TOPSOIL) :LTY SAND -MOIST DARK GRAY, GRAVELY SILTY SAND (DECOMPOSED GRANITE) MOIST MEDIUM DENSE DENSE TO VERY DENSE TRENCH ENDED AT Z /\ SOUTHERN CALIFORNIA SOIL A TESTING,INC. SUBSURFACE EXPLORATION LOG /\ SOUTHERN CALIFORNIA SOIL A TESTING,INC. LOGGED BY: CRB OATE LOGGED: 12-15.82 /\ SOUTHERN CALIFORNIA SOIL A TESTING,INC. JOB NUMBEK: 9021049 Plate No. 8 •SI z ; T R ENCH NUMBE R < I r ' SI I « I — X UJ ^ X Z < 03 Q. — 0. O < z UJ E < a. X < • ESC?^ IPTIC.N > > ,— — UJ z — UJ OJ cn CO X r-z Z UJ UJ — 1- tfl Q a 10 TE z S o CO o X Q z COI UJ o > — Z o SM/ I RED BROWN. CLAYEY SILTY iC I SAND (TOPSOIL) MOIST MEDIUM DENSE GM BAGI GRAY, SANDY GRAVEL (METAVOLCANIC ROCK] MOIST DENSE TO VERY DENSE J I TRENCH ENDED AT 5' TRENCH NUMBER TQ-9 CK YELLOW BROWN, SILTY SAND (DECOMPOSED GRANITE) MOIST DENSE TO VERY DENSE 128.1 10.1 TRENCH ENDED AT 6' SOUTHERN CALIFORNIA SOIL ATESTING,INC. SUBSURFACE EXPLORATION LOG LOGGED BY: CRB DATE LOGGED: 12-15-82 o Ji > z N m o 03 c H O z 5 U3 O ro I—" O Ol 5 o I 00 0 z n 2 o > cn t/1 I cn I X I 36- 18' I OOl 90 SO 70 I 60 u. so U I. «» 30 1. 20 10 0 i IOOO standard Sieves Hydrometer y^ \/^- %\Q #20 »40 (Minutes) •30 . l!tiq. "IQO «'20O ' 2 s JO 00 9 * I « S « J Groin Sue (mmj »•7« 9 « J 2 -1 IOU :)Ci eo 70 Ul itl i I * ) i 10' »« h 3"'"' ^ 20 —• 1 BOULDER!COBBLES 1 GRAVEL SANO SILT OR CLAY 1 BOULDER!COBBLES 1 Coorit Fin* Coar** 1 Mfdlum 1 Fina SILT OR CLAY (12 In ) 3 in. I) '4 In. No .4 No.lO No.40 No.200 U. S. STANDARD SIEVE SIZE TQ-2 (3 3' Tq-2 @ 4'-5' TQ-8 (3 4'-5' 1 I |:.AMPLE MAXIMUM DENSITY & OPTIMUM MOISTURE CONTENT ^STM D1557-7S METHOD A DESCRIPTION Maximum Density Optimum Moisture ->1 3 2 -3' • Yellow Brown, Silty Gravelly Sand 114.8 13.8 a 2 j Green Brown, Sandy Silty Clay 114.0 15.0 4 - D i Yellow/Reddish Brown, Silty Sand 112.6 14.8 ? 3' -4' j Grey, Silty Sandy Gravel 128.4 11.7 • 1 I i I EXPANSION TEST RESULTS SAMPLE iDNDITION 'HTIAL M.C.C/.) TQ-: LJ 2'-3' Remoi ded lt3.1 TQ-2 (3 3'-4' Remolded 14.8 NITIAL ZEMSITY (PCFI .01, 101.8 i i NAL M.C. (•/.) 30.5 26.0 ^NORMAL STRESS (PSF) IXPANSION % 150 .5.0 150 0. I I SOUTHERN CALIFORNIA SOIL A TBSTING, INC. CALAVERA HEIGHTS-VILLAGE W-X-Y BY: KAR JOB NUMBER: 9021049 DATE: 1-10-84 Plate No. 11 O H PI VI H (A o c H Z m ai o r i s Ik OR |o IOI Iz |c |c •• KAR O lm KAR > f— AV 1 ^ m 1 o pa 1 ^ > I •—' 1 o 1 m 1 ^ »—1 tn —) o (/I 1 "o • lat T K • 1 C . t 4 r-m LA z CT o m o s: *—* u> 1 1 UD X 1 O -< _DV£fiSIZ£L_fiQCK-X3ISRQSAL ( birucliirol Soil-Rock fill) P/L 2. •ons C<Mp«ctld loll nil IMII CMtllR It 40 ptrctnl toll itiM MiliM 3/4.Uck lUtt. (by .light), md t« C0M^«cl«4 U iccM>«i«u vlU IMCirtcilloAi for ItrMCtMril fill. Irnir" * not piraltim im A. lout I: lOnl C: IONC 0: UGtNO Co-p«l*d ,01! fdl. Hu rod f.*9«.„„ o.ir t Inchev In ,rejlM( «ofki I la 4 fttt In d(,«fl,|on pljcid In ruapKlcd toll nil confuming u lOHt A «OtU » InthM 10 2 tttl In .ol... <|«;„,|,n u„,for.l, tlurltu- ** V "*." "•0»c»»«l loll fill „«f,r.lM le 10^ t coip^cHon. J0« A. B. or C •ilerlil »,y be ulcd for ZOW 0. SLOPE ST,;BIL:-Y CALCULATIONS Janbu's Simoiifiea Slooe Stability Methoa \C(7) = WH^iGn(^ FS = Ncf(-C WH ' Assume Homogeneous Strenath Parameters througnout the siooe ^ (°) C(psf) W.(pcf) Incl. H (ft) 38 200 130 2:1 35 2.2 Metavolcanic & Gr-anitic Rock * Cut & Fill Slopes Average Shear Strength Values Where: .3' C w s H FS Angle of Internal Friction Cohesion (psf) Unit weight of Soil (pcf) Height of Slope (ft) Factor of Safety yv SOUTHBRN CALIFORNIA CALAVERA HEIGHTS - VILLAGE W-X-Y y^fy SOIL A TBI BTINQ,INC. BV: KAR DATE: 5-03-90 JOB NUMBER: 9021054 Plate No. 15 p I «CAKeNEO PLANE JONTS 10 SLABS IN EXCESS OF 10 FEET IN WIDTH TRANSVERSE WEAKENED PLANE JOINTS 0* ON CENTER (MAXIMUM) PLAN NO SCALE w/2 H/2 ! \ SLABS' 5 TO 10 FEET IN WIDTH n TOOLED JOINT T/2 / r: (6'x6--10/l0) WELDED WIRE MESH \ V WEAKENED PLANE JOINT DETAIL NO SCALE SOUTHERN CALIFORNIA SOIL 1 TESTINQ, INC. CALAVERA HEIGHTS-VILLAGE W-X-Y BYI KAR JOB NUMBgWt 9021049 DATEt .. 5-03-90 Plate No. 16 WATERPROOF BACK OF WALL PER ARCHITECTS SPECIFICATIONS 3/4 INCH CRUSHED ROCK OR MARIDRAIN SOOO OR EQUIVALENT QEOFABRIC BETWEEN ROCK ANO SOIL 4" DIAMETER PERFORATED PIPE HOUSE ON QRAOE SLAB HOUSE RETAININQ WALL SUBDRAIN DETAIL NO SCALE SOUTHBRN CALIFORNIA SOIL A TESTING, INC. CALAVERA HEIGHTS-VILLAGE W-X-Y BY: KAR JOB NUMBER: 9021049 DATE: 5-03-90 Plate No. 17 RIPPABiLITY NDEX cJt^H NO RIPPING SOFT MEDIUM HARD BLASTING 1000 2000 "3000 4000 5000 SOOO 7000 8000 9000 10000 VELOCITY. FT./SEC RESULTS TRAVERSE NO. S73-5 S73-6 S73-8 a Ib OTE: S73-9 a I b / / /I /I S73-l( S73-1 .'k S73-l^S73-i; S73-l( / 1 a I & THE ABOVE RESULTS ATTEMPT TO SHOW DEPTHS TO HORIZONS OF VARYING DENSITY INDIFFERENT LOCATIONS OVER THE STUCTC AREA. SEISMIC TRAVERSE NUMBERS^ REFER TO LOCATIONS PUTTED ON ATTACHED PLANS THE RIPPABIUTY INDEX'lS A MODIFICATION OF CHARTS BY THE CATERRLLAR CO. AND ARTICLE IN 'ROADS AND STREETS; SEPT^ 1967. ^itKriLUAK SOUTHERN CAUFORNIA TESTING UBORATORY, INC. ttaO RIVEROALE STREET BAN OlCOa CAUFORNU 92120 714'4BM134 CALAVERA HEIGHTS-VILLAGE W-X-Y SEISMIC RESULTS BY DBA X>B NO. 9021049 DATE ^-U-73 Plate No. 18 RIPPABiLITY NDEX NO RIPPING SOFT MEDIUM 1000 2000 3000 40O0 soto 6O00 7o'oO 8000 9000 10000 VELOCITY, FT/SEC. RESULTS TRAVERSE NO. 3PH OTE NUMBERS^ REFER TO LOCATIONS PLOTED ON ATTACHED PLANS THE RIPPABIUTY INDEX* IS A MODIFICATION OF CHARTS BY THF rATe-Bai i AO CO. AND ARTICLE IN 'ROADS AND STREETS; SEPT^; l^Z CATERRLLAR I SOUTHERIM CALIFQRIMIA SOIL & TESTIIMC3 LAB, IIMC. •••a RivanoAUB mTrtmur BAN DiaOQ, CALIPORNIA BBIBO SEISMIC RESULTS CALAVERA HEIGHTS-VILLAGE W-X-Y DBA xn NO. 9021049 DATE 1-11-83 Place No. 19 RIPPABILITY NDEX NO RIPPING SOFT MEDIUM HARD BLASTING i ! I i 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 IOOOO VELOCITY, FT/SEC. RESULTS TRAVERSE NO. GEDPH UJ Q a IT a j b J_U2-a |& a_jj2_ I DPM^i^v^Mm^L^S^'"^^ ^•^^'^''^ '° SHOW DEPTHS TO HORIZONS OF VARYING S.^JIL =J UXZATIONS OVER THE ST UOT AREA. SEISMIC TRAVERSE NUMBERS^ REFER TO LOCATIONS PIOTED ON ATTACHED PUNS THE RIPPABIUTY INDEX'IS A MODIFICATION OF CHARTS BY THE CATERRLLAR CO. AND ARTICLE IN 'ROADS AND STREETS; SEPT, 1967. ^.AlERPlLLAR SOUTHERN CALIFORNIA SOIL & TESTING LAB, INC. BBBO RIVKRaAUB STRBBT BAN OIBOO, CALIPORNIA BBIBO SEISMIC RESULTS CALAVERA HEIGHTS-VILLAGE W-X-Y DSL CATERPILLAR PERFORMANCE HANDBOOK Edition 17 October 1986 Seismic Velocity »•« PT •Mowg I ,000 TOPSOIL CLAY IGNEOUS ROCKS GRANITE 3A8AUT SEDIMENTARY ROCKS 3HAI.E SANDSTONE SILTSTONE CLAYSTONE CONOLOMERATE METAMORPHIC ROCKS SCHIST 3LATE RIPPABLE DBL Ripper Performance • Mum or Single Shank No. a Ripper • ^"^"""^^^ seismic wave Velocities SOUTHERN CALIFORNIA SOIL & TESTING, INC. CALAVERA BY: KAR jOB NUMBER.- 9021049 MEIGHTS-VILLAGE W-X-Y PATE: 5-03-90 Plate No. 21 DSL CATERPILLAR PERFORMANCE HANDBOOK Edition 17 October 1986 Seisinic Velocity TOPSOIL CLAY IGNEOUS ROCKS QRANITE 3ABALT SEDIMENTARY ROCKS 3 HALE 3AN08T0NE SILTSTONE CLAYSTONE CONOLOUERATE METAMORPHIC ROCKS SCHST SLATE niPPABLE D9L Ripper Performance • or Single Shank No 9 Rinn«r • Estimated bv Sei.»mi^ « oy seismic Wave Velocities SOUTHERN CALIFORNIA SOIL & TESTING, INC. BY; KAR JOB NUMBER.. 90210^0 Dl 1N CATERPILLAR PERFORMANCE HANDBOOK Edition 17 October 1986 Seismic Velocity •••I Par SMM 1 IOOO TOPSOIL CLAY IQNEOUS ROCKS GRANITE BASALT SEDIMENTARY ROCKS SHALE SANOSTONE SLTSTONE CLAYSTONE CONOLOMERATE METAMORPHIC ROCKS SCHIST SLATE RIPPABLE MAROINAL 10 n 12 _13 V4 15 I I i ! "(ZZZZZZZZZZZZZZZ ZZZZZZZZZZZ, TZZZZZZZZZZZZ. NON-RIPPABLE W//" D1 1 N Ripper Performance • Multi or Single Shank No. 9 Ripper • Estimated by Seismic Wave Velocities SOUTHERN CALIFORNIA SOIL S. . TESTING, INC. CALAVERA HEIGHTS-VILLAGE W-X-Y BY: KAR JOB NUMBER: 9021049 DATE: 5-03-90 Plate No. 23 CALAVEHIA HEIGHTS VILLAC3ES W-X-Y, TAMARACK AND COLUSGE BOULEVARD, CARLSBAD RBOCMMENDED GRADING SPECIFICATICNS - (SNERAL PFOVTSIONS GQ4ERAL INIENT The intent of these specifications is to establish procedures for clearing, conpacting natural ground, preparing areas to be filled, and placing and conpacting fill soils to the lines and grades shown on the accepted plans. The reconnendations contained in the preliminary geotechnical investigation report and/or the attached Special Provisions are a part of the Recoimended Grading Specifications and shall supersede the provisions contained hereinafter in the case of conflict. These specifications shall only be used in conjunction with the geotechnical report for which they are a part. No deviation from these specifications will be allowed, except where specified in the geotechnical report or in other written comnunication signed by the Geotechnical Engineer. GBSERV7m:GN AND TESTING Southern California Soil and Testing, Inc., shall be retained as the Geotechnical Engineer to observe and test the earthwork in accordance with these specifications. It will be necessary that the Geotechnical Engineer or his representative provide adequate observation so that he may provide his opinion as to whether or not the wrk was accomplished as specified. It shall be the responsibility of the contractor to assist the Geotechnical Engineer and to keep him appraised of work schedules, changes and new information and data so that he may provide these opinions. In the event that any unusual conditions not covered by the special provisions or preliminary geotechnical report are encountered during the grading operations, the Geotechnical Engineer shall be contacted for further reconmendations. (R-9/89) SCS&T 9021049 May 15, 1990 Appendix, Page 2 If, in the opinion of the Geotechnical Engineer, substandard conditions are encountered, such as questionable or unsuitable soil, unacceptable moisture content, inadequate conpaction, adverse weather, etc.; construction should be stopped until the conditions are remedied or corrected or he shall reconmend rejection of this work. Tests used to detennine the degree of conpaction should be performed in accordance with the following American Society for Testing and Materials test methods: Maximum Density & Optimum Moisture Content - ASTM D-1557-78. Density of Soil In-Place - ASTM D-1556-64 or ASTM D-2922. All densities shall be expressed in terms of Relative Compaction as determined try the foregoing ASTM testing procedures. PREPARATICN QF AREAS TO RECEIVE FILL All vegetation, brush and debris derived from clearing operations shall be removed, and legally disposed of. All areas disturbed by site grading should be left in a neat and finished appearance, free from unsightly debris. After clearing or benching the natural ground, the areas to be filled shall be scarified to a depth of 6 inches, brought to the proper noisture content, conpacted and tested for the specified minimum degree of conpaction. All loose soils ijn excess of 6 inches thick should be removed to firm natural ground v^ch is defined as natural soils which possesses an in-situ density of at least 90% of its naximum dry density. (R-9/89) SCS&T 9021049 May 15, 1990 Appendix, Page 3 When the slope of the natural ground receiving fill exceeds 20% (5 horizontal units to 1 vertical unit), the original ground shall be stepped or benched. Benches shall be cut to a firm conpetent formational soils. The lower bench shall be at least 10 feet wide or 1-1/2 times the the equipment width whichever is greater and shall be sloped back into the hillside at a gradient of not less than tvro (2) percent. All other benches should be at least 6 feet wide. The horizontal portion of each bench shall be conpacted prior to receiving fill as specified herein for conpacted natural ground. Ground slopes flatter than 20% shall be benched when considered necessary by the Geotechnical Engineer. Any abandoned buried structures encountered during grading operations must be totally removed. All underground utilities to be abandoned beneath any proposed structure should be removed from within 10 feet of the structure and properly capped off. The resulting depressions from the above described procedures should be backfilled with acceptable soil that is conpacted to the requirements of the Geotechnical Engineer. This includes, but is not limited to, septic tanJcs, fuel tanks, sewer lines or leach lines, storm drains and water lines. Any buried structures or utilities not to be abandoned should be brought to the attention of the Geotechnical Engineer so that he may determine if any special recomrendation will be necessary. All water wells which will be abandoned should be backfilled and capped in accordance to the requirements set forth by the Geotechnical Engineer. The top of the cap should be at least 4 feet below finish grade or 3 feet below the bottom of footing whichever is greater. The type of cap will depend on the diameter of the well and should be determined by the Geotechnical Engineer and/or a qualified Structural Engineer. (R-9/89] SCS&T 9021049 May 15, 1990 Appendix, Page 4 FILL MATERIAL Materials to be placed in the fill shall be approved by the Geotechnical Engineer and shall be free of vegetable matter and other deleterious substances. Granular soil shall contain sufficient fine material to fill the voids. The definition and disposition of oversized rocks and expansive or detrimental soils are covered in the geotechnical report or Special Provisions. Ejqpansive soils, soils of poor gradation, or soils with low strength characteristics may be thoroughly mixed with other soils to provide satisfactory fill material, but only with the explicit consent of the Geotechnical Engineer. Any import material shall be approved by the Geotechnical Engineer before being brought to the site. PLflCING AND COMPACTION OF FILL Approved fill material shall be placed in areas prepared to receive fill in layers not to exceed 6 inches in conpacted thickness. Each layer shall have a uniform moisture content in the range that will allow the compaction effort to be efficiently applied to achieve the specified degree of compaction. Each layer shall be uniformly compacted to the specified minimum degree of compaction with equipment of adequate size to economically conpact the layer. Conpaction equipment should either be specifically designed for soil conpaction or of proven reliability. The minimum degree of conpaction to be achieved is specified in either the Special Provisions or the reconmendations contained in the preliminary geotechnical investigation report. When the structural fill material includes rocks, no rocks will be allowed to nest and all voids must be carefully filled with soil such that the nvinimum degree of compaction recommended in the Special Provisions is achieved. The maximum size and spacing of rock permitted in structural fills and in non-structural fills is discussed in the geotechnical report, when applicable. (R-9/89) SCS&T 9021049 May 15, 1990 Appendix, Page 5 Field observation and conpaction tests to estimate the degree of conpaction of the fill will be taken by the Geotechnical Engineer or his representative. The location and frequency of the tests shall be at the Geotechnical Engineer's discretion. When the conpaction test indicates that a particular layer is at less than the required degree of conpaction, the layer shall be revrorked to the satisfaction of the Geotechnical Engineer and until the desired relative conpaction has been obtained. Fill slopes shall be conpacted by means of sheepsfoot rollers or other suitable equipment. Conpaction by sheepsfoot rollers shall be at vertical intervals of not greater than four feet. In addition, fill slopes at a ratio of tvo horizontal to one vertical or flatter, should be trackroUed. Steeper fill slopes shall be over-built and cut-back to finish contours after the slope has been constructed. Slope conpaction operations shall result in all fill material six or more inches inward from the finished face of the slope having a relative conpaction of at least 90% of neucimum dry density or the degree of conpaction specified in the Special Provisions section of this specification. The conpaction operation on the slopes shall be continued until the Geotechnical Engineer is of the opinion that the slopes will be stable surficially stable. Density tests in the slopes will be made by the Geotechnical Engineer during construction of the slopes to determine if the required conpaction is being achieved. Where failing tests occur or other field problems arise, the Contractor will be notified that day of such conditions by written communication from the Geotechnical Engineer or his representative in the form of a daily field report. If the method of achieving the required slope conpaction selected by the Contractor fails to produce the necessary results, the Contractor shall revrork or rebuild such slopes until the required degree of conpaction is obtained, at no cost to the Owner or Geotechnical Engineer. (R-9/89) SCS&T 9021049 May 15, 1990 Appendix, Page 6 COT SLOPES The Engineering Geologist shall inspect cut slopes excavated in rock or lithified formational material during the grading operations at intervals determined at his discretion. If any conditions not anticipated in the preliminary repxDrt such as perched water, seepage, lenticular or confined strata of a potentially adverse nature, unfavorably inclined bedding, joints or fault planes are encountered during grading, these conditions shall be analyzed by the Engineering Geologist and Soil Engineer to determine if mitigating measures are necessary. Unless otherwise specified in the geotechnical report, no cut slopes shall be excavated higher or steeper than that alloved by the ordinances of the controlling govemmental agency. ENGINECRING; OBSERVATICN Field observation by the Geotechnical Engineer or his representative shall be made during the filling and conpacting operations so that he can express his opinion regarding the conformance of the grading with acceptable standards of practice. Neither the presence of the Geotechnical Engineer or his representative or the observation and testing shall not release the Grading Contractor from his duty to compact all fill material to the specified degree of compaction. SEASON UMTTS Fill shall not be placed during unfavorable weather conditions. When work is interrupted hy heavy rain, filling operations shall not be resumed until the proper moisture content and density of the fill materials can be achieved. Danaged site conditions resulting from veather or acts of God shall be repaired before acceptance of vork. (R-9/89) SCS&T 9021049 May 15, 1990 Appendix, Page 7 RBCQMMENLED GRADING SPBCIFICKnONS - SPECIAL PROVISICWS RELKEIVE GCMPACTION: The niinimum degree of compaction to be obtained in conpacted natural ground, conpacted fill, and conpacted backfill shall be at least 90 percent. For street and parking lot subgrade, the upper six inches should be conpacted to at least 95% relative conpaction. EXPAtEIVE SOILS: Detrimentally expansive soil is defined as clayey soil which has em expansion index of 50 or greater when tested in accordance with the Uniform Building Code Standard 29-C. OVERSIZED MKIERIAL: Oversized fill material is generally defined herein as rxxrks or lunps of soil over 6 inches in diameter. Oversize materials should not be placed in fill unless reconmendations of placement of such material is provided by the geotechnical engineer. At least 40 percent of the fill soils shall pass through a No. 4 U.S. Standard Sieve. HWNSrnaN miS: where transitions between cut and fill occur within the proposed building pad, the cut portion should be undercut a minimum of one foot below the base of the proposed footings and reconpacted as structural backfill. In certain cases that vould be addressed in the geotechnical report, special footing reinforcement or a combination of special footing reinforcement and undercutting may be required. ; R-9/89)