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HomeMy WebLinkAboutCT 76-12; 5201 Shore Drive Rear Yard; Soils Report; 1989-05-09- - ..- - L i i- i- - i f ,- ?L.. .- LIMITED GEOTECRNICAL INVESTIGATION FOR PLANNED REAR YARD IMPROVEXRNTS AT 5201 SHORE DRIVE, CARLSBAD, CALIFORNIA ENGINEERING DEPT. LIBRARY City of Carlsbad 2075 Las Palmas Drive Cartsbad, CA 92009-4859 FOR MR. ANDMRS. DUANE CLOUD Prepared By WILLIAM R. UUNSON. INC. AND LOTUS CONSULTING ENGINEERS, INC. (PROJECT NO. 890423) William R. Munson CI piofessionol corporation - consulting engineering geology ..- - May 9, 1989 Lotus Project No.890423 Mr. and Mrs. Duane Cloud 5201 Shore Drive ~._ Carlsbad, CA 92008 - SUBJECT : - - DescriDtion: Leual - Limited Geotechnical Investigation for Planned Rear Yard Improvements at 5201 Shore Drive, Carlsbad, California. Lot 9, Map No. 2696, Portion of Lot Ii, Map No. 023; A.P. #210-061-09. Dear Mr. and Mrs. Cloud: In accordance with your authorisation, a limited geotechnical exploration/investigation was conducted in the rear yard of the subject - property on 12 April 1969. The subject investigation was conducted to evaluate subsurface conditions, from a geotechnical standpoint, as the basis for anticipating ground conditions to be encountered by the planned excavations: and for formulating recommendations of earthwork - specifications, and foundation design parameters and criteria for the - design engineering and construction of planned rear yard patio construction. The investigation and preparation of this report utilized .- 32302 camino Capistrano . suite 207 l son juan capistrano . 92675 . p.o. box 857 l (714) 661-2902 . - -. - - - - - - - - .- ,- - - ______ --;-------,- ‘4FY’ ~~~~:, I* L L---L- ,~ pA---- 4~: 1 % I i ,.-----I ,I;‘,‘c Sir&et Index Map - - : @i<yq - I ;\:: y&J) k;, - *. ‘\,’ \ . . . . I J 20’ 469 Topographic index Maw Mr. and Mrs. Duane Cloud -2- - - - - - - - - - - a site plan and building plans prepared by Hans Ulrich Zwar Architecture of Encinitas, California, and the 8 December 1988 geotechnical investigation report by William R. Munson, Inc./Lotus Consulting Engineers, Inc. for residential developmenton the northerly-adjacent vacant lot. NOTE: The investigation, laboratory testing, geotechnical engineering/engineering geologic evaluation and analyses, and preparation of this report were conducted jointly by William R. Munson, Inc. and Lotus Consulting Engineers, Inc. (Project No. 890423). - 0 Geotechnical Engineering: 0 Owner: Mr. and Urs. Duane Cloud 5201 Shore Drive Carlsbad, CA 92008 (619) 438-4154 Lotus Consulting Engineers, Inc. 23112 Alcalde Drive, Suite C Laguna Hills, CA 92653 (714) 768-4466 William R. Munson; Inc.~ (714) 661-2901 Hans Ulrich Zwar 1873 N. Vulcan 3, Encinitas, CA 92024 (619) 944-6433 - 0 Engineering Geology: - 0 Architecture: - PRINCIPALS - J/9/89 WILLIAM R. MUNSON, INC./LOTUS CONSULTING ENGINEERS, INC. Mr. and Mrs. Duane Cloud -3- - - - - - - .- - - - - - - 0 Structural Engineering: Delta Engineering Cardiff By the Sea, California (619) 942-8649 0 Governmental Agencies: California Coastal Commission; City of Carlsbad SCOPE The scope of the investigation included the following geotechnical tasks: 0 Review of the site specific topographic survey/grading plan data and relevant published geotechnical data. 0 Review of the December 1988 geotechnical investigation report for the northerly-adjacent property. 0 Reconnaissance of geomorphic, geologic, and man-made features at the site and contiguous areas. 0 Subsurface exploration, consisting of examination, measurement and logging of three (3) exploratory backhoe trenches that ranged in depth from 6.0- to 0.5-feet. 0 The securing of relatively undisturbed samples and representative bulk samples of earth materials encountered in the exploratory backhoe trenches for the purpose of subsequent laboratory testing and/or geotechnical engineering analyses/evaluation. The undisturbed samples were obtained using a hand-held thin-wall drive tube sampling device. 0 Backfilling the three (3) exploratory trenches with earthen cuttings at the completion of the field work on 12 April 1989. 5/9/89 WILLIAM R. IIUN8ON, INC./LOW8 CONBOLTING BNQINBSR8, INC. ,- Mr. and Mrs. Duane Cloud -4- -. - - ._- - - - - - - - - - - - .- - - 0 Laboratory classification of bulk and undisturbed samples,obtained from the field exploration. 0 Evaluation and analyses of data obtained from ,the field exploration, and from subsequent geotechnical .evaluation of ,the secured samples. 0 Formulation of recommendations for earthwork grading, foundation/deck slab design criteria and.parameters,~ and for other relevant facilities. 0 Preparation of this report and accompanying illustrations. m: The scope of work did not/does not.include stability evaluationof the gunited bluff face. Within the limitations of the subject ,inveetigation,, the following attendant features and conditions were recorded and/or evaluated during the field investigation. 0 Composition and integrity of earth materials encountered in the exploratory trenches, and from samples secured,therefrom. 0 Geometry of the earthen unite encountered in the exploratory trenches. 0 Man-made alterations of the terrain. 0 Evidence, if any, of groundwater, high ground moisture, or prior conditions thereof. 0 Apparent eurficial and gross stability of the attendant terrain and proximity. 0 Engineering properties of earth materials based on megaecopic examination. 5/9/89 WILLIAM R. MUNBON, INC./LQTUB CONBULTINQ RNQINRRR8, INC. Mr. and Mrs. Duane Cloud -5- -~ _~~ -~ - -. - - - .-. - - - - - - ,- - REFERENCE8 1. Hans Ulrich Zwar, undated, The Cloud Residence Patio Addition, building plan that include site, plan, sections; elevations and details (5-sheets). 2. William R. Munson, Inc./Lotus Consulting Engineers, Inc., 8 December 1988, Bupplementary Geotechnical Investigation for a Planned Dwelling/Garage, Vacant Parcel on Bhore Drive, Carlsbad, California. 3. Weber, Harold F., 1963, Geology and Mineral Resources of Ban Diego County, California, County Report 3 of the California Division of Mines and Geology. 4. Young, J.M. and Berry, R.W., April 1981, Tertiary Lithostratigraphic Variations, Banta Margarita‘ River to Agua Bedionda Lagoon, Paper in Geologic Investigations of' the coastal Plain, Ban Diego, California prepared for the 1981 San Diego Association of,.Geologiste Field Trip (Pages 33-51). 5. Lajoie, K.R., et al, November 1979, Quaternary Marine Shorelines and Coastal Deformation, Ban Diego to Banta Barbara, California, Paper Prepared for the 1979 Geological Society of America Annual Meeting. Notice to the owner/client and all successor owners of the eubjeat property: This limited report was prepared as an information document by the undersigned .as a professional service and should not be construed as an insurance policy or guarantee against future instability. Interested parties are hereby cautioned that this report renders opinions based on interpretation of reference data and physical conditions readily evident 5/9/89 WILLIAE R. MUNBON, INC./LOTUB CONBULTINQ ENQINEERB, INC. Mr. and Mrs. Duane Cloud - - - - - - - - -_ - - - - - - - - at the site and proximity at the present time, and,does not predict future events and conditions that may affect the property. :Moreover, ,it does not imply knowledge of all planes of weakness and other potentially problematic conditions that may be present in the earth materials at the site between exploratory trenches, and below the lower limits of the exploratory trenches. Jg&m m GEOTECRNICAL CON8ULTANTB: The primary role ~of the geotechnical consultants is to use their professional expertise in evaluating the site's geotechnical features to ~the best of their capability, and to present professional opinions plus statements of facts as determined from the scope of work, as described heretofore (i.e., surficial examination, subsurface exploration, evaluation of secured samples, geotechnical analysis, and review of the reference documents). This information is then presented in a written manner to benefit the client in decision-making regarding a course 'of action, and the degree of risk acceptable to him in undertaking the purchase or sale of property, or the development of a planned project, or the remedy of a problematic condition. At no time do the consultants partake in the risk taking; since the decisions are always and ultimately made by the owner ‘or others. Accordingly, the consultants are not responsible for financial gains or losses accrued by the owner and/or others from this project. ENCLOBUREB 0 Figure 1 - Topographic/Geologic Index Map 0 Figure 2 - Site Plan/Geotechnical Map 0 Figure 3 - Schematic Geologic Sections A-A', B-B' and C-C' S/9/89 WILLIAM R. MUNBON, INC./LOTUB CONBULTING ENGINEERB, INC. - - - - - - - .- .- - - - - - - - - Mr. and Mrs. Duane Cloud -7- 0 Figure 4 - Logs of Exploratory Trenches T-l through T-3 0 Figure 5 - Retaining Wall Criteria 0 Figure 6 - Compaction Test (Laboratory) 0 Table 1 - Summary of Field Density Test m: Figures 1 through 4 are presented herewith to provide a visual perspective of the site terrain and proximity,,together with interpretive geologic conditions and regional relationships. Moreover, the geologic data delineated on Figures 2 and 3 are based on mapping and interpretation of in-place soils encountered in the three (3) exploratory trenches, and on terrain analysis. Accordingly, delineation of. geologic conditions and relationships at the property beyond the location'of the exploratory trenches is based solely on projections and interpretations arrived at by the use of estabilished geologic methods and logic. Nothing else is implied. PLANNED IMPROVBMENT8 According to the Reference 1 plans, the planned rear yard improvements include: 0 A recessed concrete patio deck that will join an existing wooden deck on the seaward side. 0 Perimeter retaining walls to support construction cuts made in conjunction with the excavation for the new recessed deck. There will be single maximum [+/-I 2.5-foot high retaining,walls on the seaward, northerly and southerly sides of the patio; and the easterly patio perimeter (closest to the existing dwelling) will comprise four (4) stepped planter retaining walls having an overall height of [+/-I 6-feet (below the existing dwelling pad). Moreover, the laterial continuity of the stepped planter retaining walls is to be disrupted by concrete stairs. S/9/89 WILLIAM EL. MUN8ON, INC./LOTUB CONBULTIM BNOINEERB, INC. Mr. and Mrs. Duane Cloud -8- .- - - - - - __ - - - - 0 Appurtenances at the patio deck include wooden benches and a BBQ pit. 0 Extending the gunited bluff face to the new seaward patio retaining wall for erosion protection. e : :_< '_ ., 0 Installation of a patio deck area drain in the concrete patio deck. The drain is to connect to an existing drainpipe that discharges at the toe-of-bluff. 0 Anticipated earthwork volumes are to be' 32-cubic yards cut, 42-cubic yards on-site fill, and a lo-cubic yards, import fill: BITE DESCRIPTION The seaside property is rectangular in shape, and fronts on the westerly side of Shore Drive off of Carlsbad Boulevard in the incorporated city of Carlebad. The overall dimensions are 60-feet~wide by [+/-I .180-feet deep to the mean high tide line. It backs ,.westerly .onto the base of moderately high sea cliff terrain that has a seasonally variable sandy/rocky beach beyond. The northerly adjacent property is vacant/undeveloped, and the southerly-adjacent property is developed with a long established single family dwelling. Both properties have pad elevations similar to the subject property. Terrain The seaward margin of the rear yard property is marked by a .[+/-I 25-foot high bluff face that is everywhere concealed by a gunite blanket that, reportedly, was constructed about 1972. Apparently, the gunite construction was necessitated to protect the bluff from wave action, and to arrest on-going landward erosion and gradual reduction of the building site. S/9/89 WILLIAN R. WUNBON, INC./LOTU8 CON8DLTINQ BNQINBBRB, INC. Mr. and Mrs. Duane Cloud -9- Moreover, as viewed from the property, the ,,gunite bluff protection -. extends monolithically several hundred feet northerly and southerly of - the site. The configuration of the gunited bluff, from top to bottom, comprises a [+/-I 17-foot high l/4:1 to 1:l precipitous cliff that toes out at an irregular seaward sloping natural bench, which terminates as a [+/-I - 6-foot high near-vertical face above the sandy/rocky beach. - .- - - - - - The 60-foot wide by [+/-I 95-foot deep lot of the .existing dwelling site relatively level to very slightly inclined in a southwest to seaward direction. The average pad elevation is [+/-I 39.0-feet above sea level, which is at approximately the street elevation. The terrain between the elevated lot pad and the bluff comprises a relatively uniform [+/-I 3:l to [+/-I 4:l substantially naturalslope (i.e., 14- to la-degrees) that support a sparse to locally dense groundcover of thick-bladed ice plant. Imvrovements 0 A wooden deck at the top-of-bluff, and an attached wooden stairs that descend to the gunited bench. 0 Concrete stairs between the existing brick patio deck by the dwelling, and the wooden deck at the top-of-bluff. 0 Although the details of construction of the aforementioned gunite blanket are unknown to the undersigned, the condition of the gunite S/9/89 WILLIAM R. MUNBON, INC./LOTUS CONBULTINQ EN8IWWWRB, INC. ,- Mr. and Mrs. Duane Cloud -lO- - - - - - - - - - suggests that reinforcing steel (or equal) was used and, possibly, the system was anchored by rock bolts and/or earth anchors. 0 Moreover, The gunite blanket has small weep holes to allow through drainage of migrating groundwater. The upper edge of the gunite is within a few to several feet of the planned seaward patio retaining wall. DRAINAGE Drainage of the rear elope comprises sheet flow zrunoff of incident rainfall that is received on the gunited bluff and directed to the beach, below. Existing drainage of the rear brick patio area, apparently, is drained by an area drain at the northerly end, of8 the patio ~near the dwelling corner. Reportedly, runoff collected in. .the urea -drainis discharged at the toe-of-bluff via a drainpipe. GEOLOGIC BETTING Regionally, the property is regionally situated on the coastal plain at the seaward margin of the foothills of the Santa Ana Mountains, which comprises a part of the Peninsular Range Province. Locally, the underlying Santiago formation bedrock of Eocene age is capped by Quaternary marine terrace deposits. QEOMORPROLOGY The near-level to gently seaward sloping surface of the existing building S/9/89 WILLIAM R. NUNBON, INC./LOTUB CON8ULTINQ ENQINWERB, INC. Mr. and Mrs. Duane Cloud -ll- - _,~~. .- - ._ - - - - site is a substantially natural platform that is widespread in the coastal plain of the Carlsbad-Oceanside area in Northwest San Diego County. There, it is generally [+/-I 30- to 40-feet above sea level. The feature comprises the remnant of a late Pleistocene marine terrace and superimposed ancient beach deposits that emerged from the ocean 65 to 120 thousand years ago. The sandy beach sediments, termed marine terrace deposits, were formed on a truncated bedrock platform (i.e. marine terrace) cut by wave action at a time when sea level was roughly ZO- to 4%feet below the present ocean level (i.e. during Pleistocene Ice Ages when global glaciation caused a corresponding lowering of sea level). The process of the ensuing emergence to the present terrace level has been tectonic (i.e. by mountain building forces) at a continuing very gradual rate. Although imperceptible, the rate of movement is measureable by sophisticated equipment over a period of many months or years. GEOTECBNICAL CONDITIONB (Based on the Exploratory Trenches) Earth Materials 0 u - Minor, being limited to a localised [+/-I l-foot thick prism of silty sand with admixed glass and bone fragment, located at the seaward margin of the planned new patio site. 0 marine Terraoe Devosits (symbol -Qtm) - The gently dipping wave-cut marine terrace platform (i.e. bedrock) is capped by an estimated 14- to 16-foot thick prism of pale yellowish brown slightly silt to silty, very fine to medium grained sand. These ancient beach 5/9/89 WILLIAM R. I[UN~ON, INC./LOTUB CONBULTINQ~I~NGINEERB, INC. Mr. and Mrs. Duane Cloud -12- -- sediments are dense, very friable to moderately cemented (imparted by iron oxide and natural salt compounds), non-expansive, very permeable, and generally erosive. - 0 Bedrock (symbol - Ts) - Concealed by the gunite blanket of the - bluff is the underlying Santiago formation bedrock which forms the lowermost [+/-I 8- to 12-feet of the bluff (estimated). It consists of crudely stratified dark gray-brown clayey siltstone that is very stiff to hard, and exhibits moderate to high - expansivity. Moreover, the fine grained bedrock is generally impermeable and relatively erosion resistant. 0 The circa 1972 gunite blanket appeared to be substantial in place as orignally constructed. The only evidence of distress is several minor hairline cracks, and some exfoliation (i.e., sheeting-off) of /- the gunite on the near-vertical rise below the gunited lower edge. Geolosic BtNOtUre Based on outcrops in the general area, available published data, and interpretation of site conditions, the following determinations are made: 0 The marine terrace sands are very crudely to indistinctly stratified, with low angle seaward dips. 0 The Santiago bedrock strata dip 3- to 6-degrees seaward (i.e. westerly), and are cut by a system of high angle (i.e. near-vertical) joint fractures that strike roughly north-south and east-west, respectively. Groundwater Groundwater - seepage in ocean bluffs is commonplace in the coastal margin S/9/89 WILLIAM R. MUNSON, INC./LOTUB CONSULTING ENGINEERR, INC. .- Mr. and Mrs. Duane Cloud -13- of Southern California. Typically, water derived from incident rainfall - and irrigation percolates downward through the relatively permeable granular terrace deposits until reaching relatively impermeable wave-cut surface of the bedrock. The groundwater then migrates seaward at the top of the bedrock until it lldaylightsll as seepage in the bluff. Although not evident at the site or proximity due to the gunite blanket, the above described relationships are believed to exist. - - ! - INVESTIGATION FINDINGS 0 The attendant sloping rear yard area is substantially natural, as indicated by the remnant 6- to 124nch thick mantle of remnant residual topsoil that exhibits an earthy-appearing silty fine sand composition.~ 0 The exploratory trenches, which were advanced to depths ranging from 6- to 8.5:feet, revealed that the site soils are generally everywhere underlain by dense fine sands assigned to the Pleistocene age marine terrace deposits. 0 The exploratory trenches did not penetrate the terrace deposits and, therefore, did not encounter the underlying Santiago formation bedrock. 0 The exploratory trenches encountered no groundwater or abnormally high groundmoisture; and the vertical trench walls exhibited no major caving during the period that the trenches were left open. However, the upper l- to 2-feet of topsoil and weathered terrace deposits were relatively loose compared to the deeper terrace deposits. 5/g/09 WILLIAM R. RUNSON, INC./LOTUB CONBOLTING ENGINEERS, INC. Mr. and Mrs. Duane Cloud -14- -- - _- - - 0 The apparent integrity of the terrace sands is attributed to the tight packing of the sand grains and iron oxide cementation: and, possibly, to a very minor clay fraction. 0 The dense terrace sands were slightly to moderately friable, depending on the amount of iron oxide cementation and clay fraction. 0 The seaward slope between the bluff and lot pad may have been modified by shallow excavation, and filling, based on the evident thin residual topsoil mantle and localized fill. SEISMICITY/FAULTING There are no active or potentially active faults that are known to transect the property. The nearest known location of major faulting is the fault zone [+/-I 3-miles offshore, which is associated with the Rose Canyon Fault. The Rose Canyon Fault, which has been classified potentially active to possibly active (i.e. it is controversial), may be linked with the active Newport-Inglewood Structural Zone that parallels the coastline. The magnitude 6.3 Long Beach earthquake was caused by a sudden strain release along this structural zone of faulting. Accordingly, a magnitude 6.0 and 6.5 earthquake may occur within the economic life of the structure (i.e., 50 to 100 years). Of course, there are numerous other faults in the Southern California region that have the potential for generating strong ground shaking at the site. Accordingly, the planned construction should incorporate standard aseismic design considerations to mitigate the effect of ground shaking induced by a moderate earthquake along a nearby fault (i.e., 5/g/09 NILLIAR R. RUNSON, INC./LGTUS CONSULTING RNGIMRRB, INC. Mr. and Wrs. Duane Cloud -15- .- - - - - - - - - - - Newport-Inglewood, Rose Canyon, and Whittier-Elsinore), or by a major or great earthquake generated along a distant fault (i.e., San Andreas or San Jacinto). Earthcuakes during 1986 and 1987 On 8 July 1986 the site was shaken by a magnitude M=6.0 earthquake that was centered on the Mission Hills Fault (within the San Andreas Fault zone), located northwest of Palm Springs in Riverside County. Subsequently on 13 July 1986, the site was again strongly shaken by an earthquake centered [+/-I 28-miles offshore from Oceanside in San Diego County. The causative fault of the 13 July event has not been determined, but it may have been associated with the system of unnamed faults in the deep water area known as the San Diego Trough. The 1 October 1987 M=5.9 Whittier Narrows Earthquake in Los Angeles County produced vertical movement that indicated the causative fault was not the high angle strike-slip Whittier Fault, as thought initially. Rather, it was a low angle unnamed fault that trends east-west. The most severe property damage was concentrated in the older established portions of Whittier, as well as in nearby areas of San Gabriel Valley (to the north and northwest) and East Los Angeles. Orange County, which was as close as 5- to 6-miles southeast of the epicenter, experienced relatively little major damage. Reportedly, the San Diego County region was unaffected. General Seismicity Much of Southern California, including the subject site location, has 5/9/89 WILLIAM R. XUNSON, INC./LOTUS CONSULTING RNGINRERB, INC. Mr. and Mrs. Duane Cloud -16- - -~_ - - - - - ,- - - - - - - - - - been designated by the Building Seismic Safety Council (BBBC)as the most seismically active (Area 4). The rating recognizes the potential adverse influence of several major fault zones, the proximity and past. active history of which have been determined :by experts to Abe capable of generating a major shock (quake event) during ,the lifetime (35 to 50 years) of the project improvements. The subject property is located in an area of Southern California which has been subjected to ground shaking due to earthquakes ~,in: the past. Major active faults, such as the San Andreas, Whittier-Elsinore, and Newport-Inglewood are the most likely to generate earthquake events that would induce major shaking at the site. There is an 80 percent chance that an earthquake force of 0.2Og (+/-M=6.3) will be ~induced at,the ,site during the "project life". The present general trend in thedesign industry is to design the subject site and the structures to withstand'an earthquake force of about 0.2Og. The reader/reviewer of this report should be aware there is likely a lo-percent chance that the earthquake force at the site will exceed 0.4Og. ,during the "project life", and generally the effect due to this magnitude,of force is not considered in the design industry due to high cost escalation of construction. Insofar that the "state-of-the-art", as applied to the study of seismicity, is very complex and subject to continual updating, rather simplistic statistical analyses are typically undertaken. Notwithstanding this fact, a detailed statistical analysis is costly and not routinely included for that and other reasons, as is the case for this development. Consequently, we acknowledge that an earthquake with a S/9/89 WILLIAR R. RUNBON, INC./LOTUS CONBOLTING ENGINRERS, INC. Mr. and Mrs. Duane Cloud -17- - magnitude in excess of M37.0 (possible peak of 0.4Og) is possible (i.e., - the maximum credible earthquake) , and its impact is not known. However, in the event the undersigned are requested to provide such information, - we would be most glad to accommodate you in compliance to your written - request. ,- ENGINEERING PROPERTIES CF EARTH MATERIALS - SYNOPSIS 0 Marine Terrace Deoosits - Medium dense to dense: and locally hard: - non-expansive to low expansive: slightly compressible to compressible in the upper [+/-I 16-inches, and non-compressible, below, under nominal structural loads; moderately easy to excavate with conventional excavation equipment: moderately to highly erosive: and with an apparent low soluble sulfate content. Temporary construction cuts less than E-feet high should stand without major caving or other instability, provided the surfaces are maintained in a slightly moist to moist condition, are protected from rainfall, and are supported by retaining walls or backfill in an expeditious manner. - - BITE STABILITY/INTEGRITY Based on surficial examination and subsurface exploration in the rear - yard area of the site, and limited exterior examination of the dwellings and appurtenances on the subject and contiguous properties, the building - site and proximity exhibits no evidence of distress or other conditions - indicative of deleterious ground subsidence, gross slope instability, or problematic expansive soil potential in surface and subsurface soils. - J/9/89 WILLIAR R. RCNEON, INC./LOTUS CONBULTING ENGINBRRS, INC. .- Mr. and Mrs. Duane Cloud -18- - - - - I - - - - - - - - - - STABILITY BLUFF The gunited face of the bluff conceals the terrace deposits and underlying bedrock. Accordingly, evaluation/analysis of bluff face stability by the undersigned was not within the scope of work. By constrast the moderate seaward slope above the bluff exhibits friable and erosive sands. Neither the gunited bluff or the sloping terrain, above, reflects any evidence of gross slope/bluff instability. CONCLUSIONS 1. Based on the investigation described herein, it is the opinion of the undersigned that the planned rear yard patio improvements per the Referenced 1 plan is feasible from a geotechnical standpoint, subject to the recommendations rendered hereinafter. 2. The attendant terrain and structures at the project site exhibit no evidence of ground instability associated with landsliding, subsidence or settlement, potential major shrink-swell volume change, or groundwater seepage that might otherwise be problematic to the project. However, some seasonal groundwater seepage probably does occur in the bluff along the base of the marine terrace sands at the contact with the underlying Santiago formation siltstone bedrock. Weep holes in the gunite blanker allow through-drainage of the groundwater seepage. 3. Terrace deposits are deemed suitable for support of anticipated . foundation loads at shallow depths. 5/9/89 WILLIAM R. MUNSON, INC./LOTUS CONSULTING ENGINEERS, INC. Mr. and Mrs. Duane Cloud -19- .- 4. - - 5. - - 6. - - 7. - 8. Although not indicated below a l- to 3-foot depth in the exploratory trenches, some relatively weak sandy terrace deposits may be problematic to deep excavations for retaining wall and foundation construction, and may be hazardous to workers, unless construction cuts are layed-back or shored. Groundwater is a potential seasonal to perpetual condition in the zone marked by terrace/bedrock interface. However, the condition should not affect the planned construction. Earth materials at the planned subgrade levels are classified non-expansive to low expansive. Excavations in the terrace deposits for retaining walls, foundations, and utilities should be readily accomplished by conventional earth moving and trenching equipment. All clean natural on-site materials are suitable for use in retaining wall and utility trench backfill when compacted in accordance with the earthwork/grading recommendations contained hereinafter. - 9. It is anticipated that the proposed perimeter retaining walls will - - - not have to be designed to resist inordinately high ground pressures imposed by adversely oriented geologic plans of weakness, seepage pressures, and soil expansivity. 5/9/89 WILLIAM R. MUNSON, INC./LCTUB CONSULTING RNGINRERS, INC. - Mr. and Mrs. Duane Cloud -2o- - 10. The natural phenomena of downslope creep, aoil expansivity and soil sulfate attack (on concrete) are considered to impose a minor to nil influence on the planned project. - - - - - - - - - - - - 11. The project terrain is conducive for runoff to be readily collected in an area drain system and be directed to the beach in a non-erosive manner. RECORRRNUATIONS A. GENERAL 1. Based on the apparent low concentrations of soluble sulfate in the attendant soils, Type II cement (with minimum B-sacks per cubic yard of concrete and a maximum water : cement ratio of 0.54) should be used in all concrete foundations and flatwork unless shown to be otherwise by chemical testing. 2. 5/9/89 Unless otherwise recommended by the Engineering Geologist or Geotechnical Engineer during excavation, retaining wall construction cuts in the residual topsoil/terrace deposits should be temporarily stable when cut no steeper than 1:l and l/2:1, respectively. Alternately, the construction cuts may be shored where the recommended inclinations are precluded by property lines and/or other conditions. Whichever method is used, the cut face is to be protected against moisture loss WILLIAM R. WUNSOR, INC./LOTUS CONSULTING ENGINRERS, INC. .- Mr. and Mrs. Duane Cloud - - -~ - - - ,- - - .- ,- - and inclement weather. These requirements are subject to modification by the Geotechnical Engineer and/or Engineering Geologist based on field inspection of excavation exposures at the outset of rough grading. 3. The applicability of California Civil Code Section 832, (which addresses lateral and subjacent support, excavations, degree of care, damage, and protection of other structures), should be determined by the owner and his designer prior to construction. 4. Notwithstanding, the project contractor should monitor ground conditions at all times for the safety and welfare of workers: and workers should always wear protective gear when working below or near construction cuts. 5/9/89 - 5. The stability of construction (temporary) cuts for retaining walls is dependent on the time of year (i.e., climatic conditions) and the period of time the cut remains unsupported. Therefore, wall construction should be initiated and completed in an expeditious manner. Regardless of the construction cut implemented, the Engineering Geologist should inspect initial wall excavations to verify the stability of the cuts and their affect on the stability of adjacent terrain. RILLIRR R. RUNSON, INC./LOTUS CONSULTING RNGINRERS, IRC. - Mr. and Mrs. Duane Cloud -22- - - ,- _s - -. - -, - - - - 6. Due to the potential of seasonal shallow groundwater seepage conditions, (i.e., vadose water), the planned retaining walls should be adequately waterproofed to prevent through-going moisture seepage. The civil engineering or structural engineering design shall include a continuous sub-drain system for handling potential seepage for onward transmission to the nearest catch basin or other approved facility. No weep holes shall be allowed in the retaining walls. (Exception: The planter walls.) 7. Except for the planter wall, all retaining walls should be equipped with an effective subdrain system for the long term collection and disposition of subsurface water. The system should include a minimum 4-inch diameter perforated pipe (perforations down) along and above the inside heel of the wall, a drainage gallery of crushed No. 3 or 4 rock or gravel placed to within 12-inches of the top-of-wall, and a geotexile filter (Mirafi or equal) placed between the crushed rock and the adjacent earth. 8. The embedment of all foundations near the rear slope should be determined by a minimum lo-foot horizontal edge distance measured from the bottom outside edge of the footing to the face of the slope. Notwithstanding, all footing embedments should comprise minimum 18-inches in approved native soil or compacted fill, and cut-fill transition support should be avoided. 5/9/89 WILLIAM 8. XUNBON, INC./LGTUB CONSULTING RNGINRRRS, INC. Mr. and Mrs. Duane Cloud -23- - - - - - ,.- ,- .-~ - -, - - - - 5/9/89 9. All rear yard drainage should be collected and conducted to the beach in a nonerosive manner. 10. No large laterally spreading rooted trees should be allowed within la-feet of the structural improvements, including hardscape. 11. No structures, including concrete flatwork, garden walls, retaining walls and other appurtenances, should derive support on/in uncompacted fill, or on/in loose soils that are prone to differential settlement and/or downslope creep movement. 12. All earthen planters should be contoured to facilitate surface runoff to approved drainage devices. The work should be done in accordance with the minimum standards of the City of Carlsbad. 13. Planter and patio deck areas may be effectively drained to the beach by installation of an area drain system (i.e., catch basins and drain pipes). The grates of the area drains should have a minimum area of 144-square inches, and the work should be accomplished by a qualified contractor. 14. Subsequent to the completion of the project, all drainage facilities on the property should be periodically water tested for efficiency and maintenance of positive drainage to the WILLIAM R. WUNSOR, IRC./LOTUS CONBULTING ENGINEERS, IRC. .- Mr. and Mrs. Duane Cloud -24- .- - - -. ,- _1 - - - - street or beach. Fouled, clogged or disrupted drainage conditions should be corrected prior to the rainy season and onslaught of major rainstorms. Moreover, all,irrigation lines should be repaired or replaced, as necessary.‘No modifications to the approved site,improvement plans shall be made unless approved by the geotechnical consultants. 15. All excavations, including those for foundatiansand retaining walls (i.e., construction cuts), should be, inspected' and approved by the Geotechnical Engineer and/or Engineering Geolog'ist, to verify anticipated conditions and/or embedment prior to further construction. 16. All requests for inspections should be made at least’40 hours in advance of the needed inspection. 17. Prior to issuance of grading and building permits, any modifications to the Reference 1 plans and specifications should be reviewed and approved by the project Engineering Geologist and Geotechnical Engineer to determine compatibility with attendant geotechnical conditions, incorporation of applicable recommendations rendered herein, and to -@rovide additional recommendations deemed necessary under the circumstances. 18. Unprotected earthen areas should be planted with a relatively - drought-tolerant, low maintenance and fast-growing - 5/9/89 WILLIAn R. WUNBON, INC./LOTUS CONSULTING ENGINRERS, INC. - Mr. and Mrs. Duane Cloud -25- - - groundcover. Irrigation should be applied at minimal rates for healthy growth. Long duration watering and saturation should be avoided to maintain ground and foundation integrity: and automatic sprinkler systems are not recommended. B. GRADING &)@ EARTRWORK Site grading will be required for: - - Excavation for the lower rear yard patio improvements. Foundation and retaining wall excavations (i.e., construction cuts) . Compacted fill subgrade for support of concrete and brick flatwork/hardscape. Retaining wall backfill. The manufacture of planter areas for positive surface drainage to approved drainage devices. Based on existing versus planned grades on the referenced site plan, the planned improvements will entail moderate excavation and fill placement in conjunction with the rear yard improvements. Most of the required fill materials may be derived on-site from the rough grading. Caution should be exercised to prevent mixing of select native or imported materials with soils containing debris and/or organic matter. Organic matter may be stockpiled in limited quantities for landscaping purposes. However, excess volumes, together with any deleterious substances, should be stripped and removed from the property. 5/9/89 WILLIAR R. WJNSON, INC./LOTUS CONSULTING ENGINEERS, INC. - Mr. and Mrs. Duane Cloud -26- - - - - Excavated soils with an organic content of less than 3 percent by volume may be blended with non-organic material in the construction of retaining wall backfills, provided this procedure receives PRIOR approval of the Geotechnical Engineer. All imported backfill soils should be washed concrete sand or other select granular material with a sand equivalency greater than 30, as approved by the Geotechnical Engineer prior to use. The uncompacted backfill placed in the exploratory trenches should be removed and replaced as compacted fill where the bottom of the trenches are below planned subgrade levels for floor slabs and appurtenances, and below planned foundation subgrades. Any surface and subsurface grading obstructions such as utility lines, loose fill, debris, trees with root systems, and existing foundations, encountered during grading should be brought immediately to the attention of the Geotechnical Engineer to assure proper exposure, removal and/or relocation, as advised. No unsuitable soil conditions, nor underground obstructions or facilities should remain in any structural areas which will receive compacted fill, foundations, and hardscape. All structural fills (existing or proposed) constructed in areas of the proposed improvements should be densified to at least 90 percent relative compaction at 115- to l20-percent of the optimum moisture content, by mechancial means only, in accordance with ASTM - Test Method D1557-82. The upper 6-inches of the subgrade exposed 5/9/89 WILLIAW R. WUWBON, INC./LCTUB CCNSULTING WNGINWERB, INC. - Mr. and Mrs, Duane Cloud -27- by stripping or excavation should first be scarified, moisture conditioned as necessary, and properly compacted. Existing native soils shall exhibit a minimum relative compaction of 87-percent with a moisture content of 115- to 120-percent of optimum moisture content. - - - - - - - Proposed fills overlying existing terrain steeper than 5H:lV slope ratio or underlain by incompetent materials shall be adequately benched into competent native marine terrace deposits. The minimum width and depth of benches shall be 5-feet and a-feet, respectively. The bottom of the benches shall slope a minimum of 5% into the sloping terrain. - - - - Depressions and/or cavities created as a result of obstruction br other removal by preparatory grading should be properly backfilled with suitable fill materials and compacted. This requirement applies specifically to abandoned cesspools, septic tanks, and similar structures which should be cleaned out, then cut off to at least 5-feet below final pad grade, and backfilled with ,select granular materials approved by the Geotechnical Engineer. 1. Excavation Conditions - Except where very hard bedrock ,is encountered (which is not anticipated), excavation of on-site materials should be accomplished with conventional earthmoving or trenching equipment. Although unlikely, excavations in hard bedrock may require heavy-duty excavation and trenching equipment by a U-9 Cat equipped with a single ripper shank, or equal; and excavations for foundations and utilities may - require jackhammering. 5/9/89 WILLIAM R. MUNSON, INC./LOTUS CONBULTING RNGINERRB, INC. - Mr. and Mrs. Duane Cloud -20- - - - - - - - ,- ,- The walls of temporary construction excavations should be cut no steeper than 1H:lV to a depth of 1.5-feet, and no steeper than 1/2H:lV thereafter, unless otherwise approved for steeper inclinations by the Geotechnical Engineer and/or Engineering Geologist based on inspection of excavation exposures. Shoring of excavation walls or laying-back the construction cut inclination w be required if the planned depths ,are increased, if property line limitations restrict the recommended slope ratios, if inclement weather prevails, or if it is determined by the Geologist or Geotechnical Engineer that the presence of unsuitable fill, in-place earth, gravel pockets, excess moisture, and/or adverse dipping strata may cause severe localized instability. -~ - - - - All work, associated with trench shoring must conform to applicable State of California Safety Code sections and/or federal OSHA regulations. Native soils may be utilized for trench backfill, provided they are approved by the Goetechnical Engineer. Flooding of the trench backfill is not permitted, and compaction should be accomplished entirely by mechanical means. 2. Shrinkaae. Swell m Subsidence - In planning the proposed grading operations, we recommend that shrinkage and swell factors of about 15- and 'I-percent be used, respectively. That is 1.15 and 0.93 cubic yards of in-place soil and rock - materials will be required to yield 1 cubic yard of properly S/9/89 RILLIAM 8. MUNSON, INC./LOTUS CONSULTING ENGINEERS, INC. - Mr. and Mrs. Duane Cloud -29- - - - - - - densified fill, without wasting, at 90-percent relative compaction. In addition, approximately 0.00-foot of subsidence should be anticipated due to reworking of native soils. - - - - - S/9/89 3. Surface J&& Subsurface Drainaae Provisions - Positive surface and subsurface gradients should be provided to direct surface and subsurface water run-off away from structural foundations or walls and towards suitable collection/discharge facilities. Ponding of surface water should not be allowed anywhere on the property. We recommend the use of gutters, downspouts, area drain systems, French drains, and subsurface drains interconnected to a permanent subdrain system with multiple at-grade inlets, especially along those portions of the perimeter of each structure or wall bordered by landscaping. Alternate drainage schemes are subject to review by the Geotechnical Engineer. The use of planters without sealed bottoms or large trees with long laterally spreading root systems in the immediate vicinity of structural improvements, including pavements, shall not be pemitted unless previously approved in writing by the Geotechnical Consultant. Wore detailed criteria for subsurface drainage systems, were deemed necessary, will be provided on request. WILLIAN R. MUNSON, INC./LOTUS CONSULTING ENQINEERS, INC. - Mr. and Mrs. Duane Cloud -3o- - - - - ,- - - - C. - - - - - - 4. Geotechnical Field u - All demolition, grading and geostructural work should be performed while observed by a representative of this firm to assure proper subgrade preparation, selection of satisfactory materials, installation of geostructural elements, placement and compaction of all structural fill. Sufficient notification prior to stripping and earthwork construction is essential, to improve the certainty that the work will be adequately obsenred. All earthwork should be performed in accordance with applicable Code sections of the City of Carlsbad. FOUNDATION CRITERIA An evaluation of in-place soil characteristics has determined that the planned conventional and retaining wall footings would be most satisfactorily founded in dense undistributed terrace deposits OR in compacted .fill. Cut-fill transitions beneath an individual foundation unit should be avoided. 1. Foundations - The new improvements may be satisfactory supported on conventional continuous footings seated into competent marine terrace deposits, as approved by the Engineering Geologist. These footings may be designed for an allowable bearing value of 2000-pounds per square foot, which may be increased by one-third, if the Structural Engineer takes into consideration short duration structural loading conditions, such as those induced by wind or seismic forces. S/9/89 IILLIAN R. MUNSON, INC./LOTUS CONSULTINQ RNQINRERS, INC. Mr. and Mrs. Duane Cloud -31- - - - - - - - - - - - - - - Continuous retaining vall footings and other footings shall be uniformly founded at least la-inches into approved undisturbed terrace deposits OR compacted fill. Individual support5 outside the structural slab areas (i.e., in landscaped areas) may be seated into approved firm soils at an increased depth of 30-inches below verified exterior grade. Footings on or close to the slope shall observe a horizontal setback of 5'~d~lO'(d=horizontal distance from outer edge of footing to slope daylight = h/2; h = height of slope). All continuous foundations should be reinforced with at least two (2) No. 4 bars, one at the top and one at the bottom to provide structural continuity, and to permit spanning of local subgrade irregularities. The minimum footing width should be 12-inches. All visible cracks in the foundation excavations should be brought to the attention of the Geotechnical Engineer to determine the need for presoaking prior to placement of the foundation concrete. The use of a chemical admix in presoaking shall be approved prior to its use. 2. Slabs m Grade - Concrete floor slabs and flatvork may be directly supported on properly prepared subgrade (i.e., dense marine terrace deposits or compacted fill). Subgrade preparation shall be in accordance with the grading and earthwork recommendations, including proof-rolling just prior to construction, to provide a firm unyielding subgrade. (Refer to Figure 3). 5/9/89 WILLIAW R. MUNSON, INC./LOTUS CONBULTINQ WNQINRERS, INC. - Mr. and Mrs. Duane Cloud -32- - - - - - - - - - - - 5/9/89 At that time, in any area where shrinkage cracks appear, these could be effectively sealed by presoaking prior to slab construction. When moisture migration through concrete slabs is undesirable, an impervious membrane (6-mil plastic or equal) should be sandwiched between the floor slab and the supporting subgrade. A l- to a-inch thick layer of clean sand placed below and over the plastic is desired to permit the preparation of a more uniform subgrade to provide a cushioning effect, to prevent the sheeting from blowing away, and to assist in a more uniform curing of the concrete slab. Proper precautions should be taken not to puncture or tear the membrane, and to wrap the plastic (Visgueen) tightly around protruding pipelines. Other methods of slab construction, including post-tensioning, which are available, should be subject to close review by the undersigned Geotechnical Engineer prior to use. Based on laboratory test data, native subgrade materials are considered to be to non-expansive to low expansive. In order to minimize crack size and the distribution of tension stresses in the concrete floor slabs and flatwork, and in consideration of the potential for non-uniform foundation material and expansive subgrade soil conditions, we recommend that minimal reinforcement consist of 6~6/#1Ox#lO WWF or X3 bars at 18-inches on center each way. The reinforcing should be WILLIAN R. MUNSON, INC./LOTUS CONSULTINQ ENQINRERS, INC. - Mr. and Mrs. Duane Cloud -33- .- - .- - - - - - - ,- adequately supported during the placement of concrete to assure positioning near the center of the slab. In addition, the minimum slab thickness should be 4-inches (nominal). NOTE: Additional testing near the completion of earthwork will be necessary, which may result in modified recommendations. All concrete flatwork should be constructed with control joints at a maximum spacing of a-feet; control joints should also be installed to effectively bisect all corners and lesser angles: and the reinforcing steel in the concrete should extend through the control joints for the purpose of structural continuity. 3. Lateral Caoacity - Lateral loads may be resisted by friction, between the floor slab or footings and the supporting subgrade. For the final grade conditions expected for this property, a friction coefficient of 0.40 is considered applicable. -. - - - In addition, lateral resistance may be provided by passive pressures acting against the foundations. We recommend a passive capacity in native soils and/or compacted fill equal to a hydrostatic pressure developed by an equivalent fluid with a density of 250PCF and 340PCF for soft slopewash deposits stiff/firm terrace deposits, respectively. - 4. Retainina Walls - Retained native soils and compacted fill will exert lateral driving forces (active) against foundations and - backfilled walls. The Gtructural Engineer's design S/9/89 WILLIAM R. MUNBON, INC./MTUS CONBULTINQ WNQINRERB, INC. - - -. - - - - - - - - - - - - - Mr. and Mrs. Duane Cloud -34- considerations should include satisfactory drainage provisions, and resistance to long-term lateral equivalent fluid pressure with a density of 36- & 43-pounds per square foot per foot of depth for level and 2H:lV (horizontal to vertical) sloping surcharges, respectively. The level backfill has been assumed to consist of silty sand: however, modified design values will result when import backfill is placed rather than native soils. These design values do not include temporary overloading conditions which could result during construction due to the use of heavy compaction equipment operating directly adjacent to such structures. D. EXPANSION CONTROLS On the basis of visual laboratory tests performed on representative samples collected by our personnel, the native materials are considered non-expansive to low expansive. The contractor should be aware that graded and moisture-conditioned subgrade soils allowed to remain uncovered during summer and fall months of the year, will dry out over a period of several weeks. Therefore, additional reworking of the soil will be essential prior to geostructural (footings, slabs, pavement, hardscape, etc.) construction. All hardscape (including the driveway) shall have 5/9/89 - WILLIAM R. MUNSON, INC./LOTUS CONSULTINQ ENSINWERS, INC. Mr. and Mrs. Duane Cloud -35- - - - - - - - - - - - - - - - - - adequate concrete thickness and reinforcement, ample construction/expansion joints, and shall be underlain by subgrade soils with a moisture content of at least 110 to 115 percent of optimum moisture at a minimum relative compaction of 90 percent. RIgK BTATEMENT The property comprises natural terrain in an area of coastal Southern California with earth materials that have been problematic to the integrity of structures, and to slope stability. Accordingly, the owner/developer and all future owners of the subject property should be apprised of the additional risk of potential slope and structural distress that accompanies development on such terrain, and the importance of the prudent construction of site improvements, drainage control and disposition, landscape irrigation, and maintenance of terrain conditions and drainage facilities. CLOBURE: The undersigned warrant that the work performed in the preparation of this limited report was accomplished in accordance with generally accepted principles and practice in the field of engineering geology and geotechnical engineering. This warranty is in lieu of all other warranties, either expressed or implied. This report was prepared to augment and facilitate the design engineering of the planned project, and is not for the benefit of a S/9/89 - WILLIAW R. MUNSON, INC./LCTUB CONBULTINO BNOINEERB, INC. - - - - - - - - - - - - - - - - Mr. and Mrs. Duane Cloud -36- third party. The findings, conclusions and recommendations are based on information and data secured from the limited field exploration, reconnaissance geologic mapping, limited laboratory testing, the referenced plans and geotechnical published data, and interpretations made therefrom. Conditions may be encountered by the grading and/or construction that may differ from thosa presented herein. Thus, the consultants should be requested to provide inspection of all excavations. a: This report describes attendant conditions and renders opinions of site conditions and stability that were apparent during 12 April 1989, based on the exploratory trenches and field examination. Therefore, the undersigned assume no responsibility for the following circumstances: Attendant geotechnical conditions that are not represented by the exploratory trench data and attendant terrain features; financial gains or losses associated with the sale of the property or future improvements by the owner and/or interested third parties, including adjacent property owners: future work of a grading, geotechnical or construction nature done by others; and damage to property associated with the site development, and with inadequate maintenance by others. Moreover, the geotechnical data delineated on Figures 2 and 3 are based on data derived from the exploratory trenches and surficial geologic mapping, and interpretations therefrom. Accordingly, the delineation of subsurface conditions and relationships is based solely on projections and interpretations arrived at by use of 5/S/89 WILLIAW R. XUNSON, INC./LOTUS CONSULTING ENQINEERS, INC. -. -. -. - - - - - Mr. and Mrs. Duane Cloud -37- established geologic methods and logic. Thus, the degree of accuracy is limited thereby. Should you have any questions regarding this report, or if we may be of further service, please contact the undersigned at your convenience. Respectfully submitted, WILLIAM R. MUNSON, INC. LOTUS CONSULTING ENGINEERS, INC. SANPATH V. RAGHAVAN, Principal Geotechnical Eng. G.E. 000705 (Expires 3/31/91) - - WRN/SVR/slm Enclosures Distribution: (4) Addressee .- 5/9/89 WILLIAM R. MUNSON, INC./LOTUS CONSULTINQ NNGINNERS, INC. -~ - - -.. -. _.. - - - - - - - .- - - - - OCEAN i . . . LEGEND Km I J fOUlfS .n %I Alluvio~ &posits / Morine Terrace Deposits El TSO Ponds or LopOOns cl 1s @ Outcrop, bcotion Topoclraphic/Geoloqic Index Map I Scale :. 19’ =; t 3.16 Source: q&j&.&+ Figure 1 Son Moteo Formotion Wliocenel Son Onofre Formction (Miocene1 Sontiogo Formotion (Eocene) ‘?I1 ., ‘\, ‘> #! I, -:*L( w. L qb$&yt$ ..&..:,:.‘:.;;r’~‘~ .-v : - .--r/E k --4&J -7f=.F.t. -~-‘.i ~._ ~_. --. . .I’ -.-~. . . .~ CF LCT a., ~~.&w&‘T’ ,-. ‘V I _ J ,’ ,, +.~I:: ? * i -; $i& ! . - I. _ .-_ -- \ - PLAN / GEOTECHNICAL MAP - . :,,I - ,. SITE I - - .- LOGS OF EXPLORATORY TRENCHES i- - - - - - - FIOURE 4 _~ -- - -- - - - .- - - - - - - - .- EXPLORATORY TRENCH NO.! - ld by: a f LCtl4t-c 3 Proj*st: ‘ /& tn.“, : 4hnch Laotlon -G.dldL Dot,: - - 1”: k3.5’ Doivn : =TL-- truth Drlentotion : hl I f UNIT Nf Qd wrll 4 & TRENCH WALL SCHEMATIC DIAGRAM sd.: ,=* I I DESCRIPTION s4ll buSt*llCy/ I owdry other 5&d, --&p -tpd:V , M&v 7- lYr& (4 CyTiJ cii~ ,LIAM R. ML SON s,l ) !?I +-0cwi2l ‘2 “Orl.,,,,. .V’~ -A &I!. .LL ?i -t-h,& LkJ&J - LA:, y-+ - &.- Sc.9. c!wlij -~ - -. - - - - - - - - - - - - - EXPLORATORY TRENCH NO. 2 Loggmd by: b Epulpm.“, z l&Lo+ ri;rlcbsi +Gw-c 2 fl Trmeb LocatIon ProJlct: f$..ld /$hD,C D “, Tnr &“L Da?*: G-12- g9 tliuda 8’ *338 Do,“n : 5 CL. -- -- -- -- - - . . . . \ ’ ___ _. .- .- 8’ , 3 38 , ,;,, Orlmto(ion ~: ~ ‘; UNIT .LIAM R. MU -TRENCH WALL SCHEMATIC DI1 DESCRIPTION - ! >GO a ,--+&-4+.&J. S’ s.q .a/ -&a .t c 3 RAM &II coust*nq/ lhSl1Y other m&& d,,r LrnJ, -,, t-e-t ha,r-r h*.w, ,a _ - .- - - - - - - - - - - - - - - EXPLORATORY Tf?ffWi NG. L I Loggd by: L f== fquri z Projwt: amcl Jltow I- Lpuipnwd 1 w-d l&K&c rllack LOcDtlon crl, - /d E / / ,/ +d. -bLti 14 JIAzJ7 Y /, ‘7-J -JlloPlC. . x UNIT .LIAM R. MU - /-‘--F-J-^-A---- hcny. 4, *-. * - -- --- Md \ bulk _~I *,.,.g -*-- / NE TRENCH WALL SCHEMATIC DIAGRAM sdr: I‘.2 DESCRIPTION SolI cmmlst~tlcy/ Dwlsey 0 c : Y 2.5 : z c T L other hod&& L--w --h-d-.? Put Xais h,,:d - h,wrL - trsh OY/di d c L<. :~, b&J.@- L ! - DESIGN NOTES I’BACK FILL MATERIALS SHALL CONSIST OF:: SE = 36 2. APPROVED FREEDRAINING MATERIALS, (CLASS.2 OR CLASS.3 A. B. OR EWtVALENTl TOtZ INCHES MINIMUM THICKNESS WITH A 4” DIAMETER PERFORATED DRAIN PIPE (ABS OR EOIJIVALENT) TO INHIBIT HYDROSTA TIC PRESSURE BUILDUP SHDUL D BE ADDED FOR WALL DESIGN. 3’A LAYER OF RELATIVELY IMPERVIOUS SOIL (CLAYEY- SILTY TYPES) TO 15 INCHES MINIMUM THICKNESS SHOULD COMeRISE THE UPPERMOST LAYER OF BACKFILL VALUES OF SLOPE ANGLE* -DEGREES 4. A MINIMUM COVER OF& INCHES SHOUL 0 BE PROVIDED OVER THE FOOT/NC; TOE. 5. WEEPHOLES SHOULD BE PROVIDED AT_8 FEET ON CENTER, EACH AT LEAST 3 INCHES IN DIAMETER, WITH NONMETALLIC =4 SCREEN INSIDE.DYHERE 6.DESIGN RESULTANT OF ALL FORCES DES’RED) MUST PASS THRWCH THE CENTRAL ONE- THIRD OF FOOTING WIDTH “8: 0 7. COMPACT BACKFILL BY APPROVED MECHAN- ICAL MEANS, BY HAND OPERATED EOUtP- (ONLY WITH MENK TO NOT LESS THAN 90 % AND EXTER’oR PAVEMENT TO NO GREATER THAN A% RELATIVE COMPACTION; uAxtmuM DRY DENSITY BASED ON: AS TM TFST Dk557-78 8. MAXIMUM ALLOWABLE TOE-BEARING PRESS- URE SHOULD NOT EXCEED 2=o PSF 9.A COEFFICIENT OF FRICTION OF-!&+.? MAY BE USED TO RESIST WALL SLIDING IO.THE WALL MUST BE FREE TO YIELD LATERALLY WARNING- DO NOT MODIFY TYPE OF BACKFILL MA TERIA L DCStG.4 FORCE (PI-Y KM d * FRtCT/cW fDRCt lFj.4 X, X2 l I RETRINING WALL Ct?l TERIA LOW WALL WITH UNIFORM SLOPE FIGURE RrPORT DATE -~ - - - -. - - - - - - - - - - - - - SUMWgW OF TEST DATA Aw.5x SAMPLE IDE-NT/?-Y: =GLw ‘L +3 @ 5’4 ’ TEST METHOD II AS TM D-15.57; 3 LAYERS 2. ASTM. D-1557: 5 LAYERS 3 CAL/E IMPACT 5 ROCK CORRECTION: OPTIMUM MOISTURE CONTENT=% MAX DRY DENS/TY ITC PCF EST/MATED: BY TEST RESULTS MATERIAL L’ESCR/PJ/O p.UST SAIJJD , Q, s\crr APROX f=G?ClSf TV- lcixs 32f2!c CURVE NO t! MOISTURE CONTENT i%2 Im)wrr-c4 COARACJION JES J F’$E I TESTED BY DATE M-B MhY eL7 ‘~ G -~ - -~ - - - - - - - - - - - - - - - - I t t t SSllKfAPY 0 IIILD DllSITY TSlT# “’ I TABLS I ;--_______----_-__-_____________________------~~~~~~~~~~~~~~~~~~---------------------. ._______________________________________-----: : ,: : NIBVI : ! : FISLD ! PISLD I I TKST : 3BST : TEST : APPSOIIl4AtE : DSPTS XEF. : II D D ! I H C I I D D RC I I TlPE I I no. : DATS I LOCATIOn : IKKGI :cNsvsl : :~ : : BKIIAEKS ~________~ ! 1989 I lsee plan1 I feet : I pcf ! \ : pcf : \ : WDT:NCI I_____:______:__________________________------~-------:-----:-------;-------~-------~-----~------------------------------~--~--:--~ : 1 I -12 : Trench 1 18’ I A I 126 ! 3.31 1oo.k: 1.11 111.2: 5.2: 116.1: Ii 101.3: 911 qtn ! Trench I Trench ! Trench 1 I 8’ 3 1 32’ 126 I 126 i 126 : : A : 2 : I 3 : 91: qt1 981 qtm III : : ! I : A 981 qt1 :I: I I : : : I : I I : , : I I : : , , s 1 I I : I I I : I : : I : I : : : I : : I , I 0 I 8 : : : : : : : : : I : : : I I : I : I : I : I I : I : : : : : I : I I : : : : : : : I ~-______________________________________----------~--------------------------------------------------~~~~~--------~~~~~~~--~~-~~~~~ Where: HDD : Salimm Dry Density; IHC 7 In-situ Hoi&we Content; IDD : In-situ Dry Density; SC = Relative Compaction; SC = Sand Cane; DT = Drive Tube; NC : Nuclear Gauge; BFG = Below Fiaiahed Grade; F.G. = yiBi:bed Grade; ~.~____~__----------____________________~~~~~~~~~~~~~~~~~~~~----------------------------------------~--~~~~~~~~~~~~~~~~~~~~~~~-~~~~ :LOTD~ I APPLIAD I PROPOSED MAR YARD IIIPSOVKHESTS : SSOSE DBIVK, CASLSSAD, CALIPOENIA COlfiULTIIC l&IT1 :---------.-------.------.-.--------------------------------.-~ : PEOJBCT IO. : TAELS : :IcIIISns ! acIIICI8 I A9421 IC I Ml 19S9 I I :