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HomeMy WebLinkAbout; La Costa Valley Meadows Unit 1; Soils Report; 1970-10-07T. FUNNEKOTTER REGISTERED GEOLOGIST CERTIFIED ENGINEERING GEOLOGIST P.O. BOX 575 ESCONDIDO, CALIFORNIA 92025 SUBSURFACE INVESTIGATION - LINES A-6 to D-6, INCLUSIVE PROJECT NO. 70-4-1F OCTOBER 7, 1970 SlOlO .17.80 LINES A-6 to D-6, INCLUSIVE >- ; . \ in- : 6 3 ,.- i- z $ 9 L - i ‘0 ul z- a : Q) o- c : 3 is 2- E ,? 3 $- 0 3- 2 P < %I zl - Purpose: To evaluate subsurface conditions at two ridge structures In the La Costa Volley area in order to anticipate any excavation problems that might be encountered. Method: Refraction Seirmogmph - Geologic Reconnaissance. Dlrcusslon: The structure investlgoted is a double ridge complex which coalesces into a common draw downslope. The ridges are composed of the familiar Black Mountain Volcanics of this area. Total Seismic coverage for this proiect is 1650 lineal feet. High velocity volcanic rock was located on every Seirmlc run. The depth of this material is from 3 feet to 12 feet below the surface. The velocity range meosured for this volcanic materiol 1s 6500 to 9500 ft/sec. Some small localized softer pockets of decomposed and fractured volcanics were located with velocities between 4000 and 5000 ft/sec. Overlylng the volconics in the areas checked is o thin residual mantle of decomposed material wlth a velocity range of 2200 to 3000 ft/sec. Conclusion: This entire area investigated exhibits high velocity volcanic rock ver,y near to the surface (up to 12 feet deep). Small isolated pockets of softer material in the 4ooO to 5000 ft/sec velocity range is indicated at seveml locations. For this type of material, the following rippobility schedule should opply: Velocity Excavation Method 0 to 2000 ft/sec Scraper 2000 to 5000 ft/sec Ripper 5000 to 5500 ft/sec Marginal Over 5500 ft/sec Drill &Shoot T. FUNNEKOTTER REGISTERED GEOLOGIST CERTIFIED ENGINEERING GEOLOGIST P.O. BOX 575 ESCONDIDO, CALIFORNIA 92025 SUBSURFACE INVESTIGATION LINES A-7 to C-7, INCLUSIVE PROJECT NO. 70-4-l F OCTOBER 16, 1970 T. FUNNEKOTTER REGISTERED GEOLOGIST CERTIFIED ENGINEERING GEOLOGIST P.O. BOX 575 ESCONDIDO, CALIFORNIA 92025 SUBSURFACE INVESTIGATION LINES A8, B8, C8 & D8 PROJECT NO. 70-4-1F OCTOBER 28, 1970 LINES A-7 to C-7, INCLUSIVE i :-- b SL T .g !L z ‘si $, -c h; c- 1 h k- i c. li - : ‘L 0 OJ *;- i i i- 3 Purpose: To evaluate subsurface conditions at selected locations in order to anticipate ony excavation problems that might be encountered. Method: Discussion: Refraction Seismogroph - Geologic Reconnaissance. This Oreo is composed of volcanics with poorly consolidated Tertiary sediments on the flanks. Total Seismic coverage for this project is 1450 lineal feet located as shown on the enclosed mop. This report includes lines A7, 87, and C7. Line A7 was run both northeast ond southwest of the main volcanic structural feature. Lines B7 and C7 was run across this structure in order to delineate the configuration more clearly. Three to four layers were mapped - the upper soil cover, the adjoining decomposed and fractured volcanic moterial, and the basement volcanics. These three layers have a velocity ronge of 1300 to 1600 ft/sec, 3500 to 4300 ft/sec, and 6300 to 7500 ft/sec. One additional layer of poorly consolidated sediments wos encountered on both flanks of line A7. This material has a velocity range of 2000 to 2700 ft/sec and thickens away from the main structure. On line A7, this material is located a distance of opprox- imately 300 feet both east and west of referencestotion 0. It probobly pinches out on the west side of Station 0 between Stations 1 and 3. The high point of the velcanic feature appears to be in the vicinity of Stotion 2 east and falling off in all directions. This structure rises to within 16 feet of the surface here and many volcanic blocks are incorporated in the softer overburden. Line B7 indicates the high point is approximately 70 feet eastward of Station 0. Line C7 indicates the feature dipping southeast. Conclusions: The subsurface investigation indicates a volcanic structural high overloin with 16 feet or more of decomposed and fractured volcanic material. The flanks of this feature indicate the presence of poorly consolidated sediments pinching out against this feature. The overburden velocities measured were 4300 ft/sec or less. In terms of rippobility, the following schedule would apply based on the cop- ability of a D-9 Cot: Velocity Excavation Method 0 to 2000 ft/sec Scraper 2000 to 5000 ft/sec Ripper 5000 to 5500 ft/sec Marginal over 5500 ft/sec Drill and Shoot LINES A8, 88, C8 8 D8 3 z Ed- : 2 x-- i! s... H tr e >- r 0” e L- a cl 2 L- 9 ‘- P t Y c- 9- i 5- F: i- a 5 a - - - Purpose: To evaluate subsurface conditions at three select areas in order to determine what excavation problems may be anticipated. Method: Discussion: Refmction Seismograph, Geologic Reconnaissance. This report includes lines A8, B8, C8, and D8 - located OS shown on the enclosed plot. Total Seismic covemga is 1500 lineal feet. Lines A8 and D8 ore extensions of old line B and are in volcanic material. A high velocity stmto (6500-6808 ft/sec) was located here at depths of 4 feet to 12 feet. The overburden velocity meosured 2500 ft/sec here. Conclusion: Line C8 which is in Tertiary sediments indicates low velocity material to depths of 40 feet or more. The velocity range of this material is 2000 to 2500 ft/sec. Line D8 is in gmnitic moteriol and wos run across old line E2. High velocity granite wos located here between 5 feet and 11 feet deep with o velocity of 7500 ft/sec. Mony boulders ore scattered throughout this area. Lines A8 and 88 ore in a volcanic area with high velocity moteriol 4 to 12 feet deep. Line C8 is in Tertiory sediments and oil low velocity moteriol. Line D8 is in gmnitics with the high velocity moteriol 5 feet to 11 feet deep. The rippability schedule for this moteriol would be as follows: Velocity Excavation Method 0 to 2000 ft/sec Scraper 2000 to 5000 ft/sec Ripper 5000 to 5500 ft/sec Marginol Over 5500 ft/sec Drill 8, Shoot - Project No. 70-4-1F Ranch0 La Costa -2- Februory 15, 1971 It is recommended that the above reports of subsurface investigations be attached as Appendix C-2 to subject report along with the report on Lines A2 to D2, inclusive, and Lines A4 to D4, Inclusive. The general considerations previously foworded ore applicable to all the subsurface investigations. A copy of Drowing No. 1 of Project No. 70-4-lF, La Cost0 Meodows Units 1 - 4 revised Feb 15, 1971 is forwarded herewith. A current print of the Master Exploration Plan for Ranch0 Lo Costa is also enclosed. - Respectfully submitted, - BENTON ENGINEERING, INC. William G. Catlin, Civil Engineer - Distr: (4) Ranch0 La Costa Inc. (2) Roncho Lo Costa Inc. Attention: Mr. Burton L. Kramer - (2) Rick Englneering Compony (1) T. Funnekotter - - - - - BEliTON EN61NtEHINi. INS SUBSURFACE INVESTIGATION - -- .- For LA COSTA VALLEY LINES A-5 to C-5, INCLUSIVE - - T . Funnekotter Registered Geologist Certified Engineering Geologist P. 0. Box 575 Escondido, California 92025 .- - - PROJECT NO. 70-4-l F SEPTEMBER 26, 1970 LINES A-5 to C-5, INCLUSIVE a ,c j ? ;i t > i: ‘t -z. : * CL i? , t 2% , 13 - Purpose: To evoluate subsurface conditions in two new select areas in the La Costa Valley area in order to anticipate any excavation problems that might be encountered. Method: Discussion: Refraction Seismograph - Geologic Reconnaissance. Both areas are composed of the same similar Volcanics - Andesite to Rhyolite - as the previous projects ond also poorly consolidated sediments on the flanks of the Volcanics. The contacts between the two types of moterial was located at three areas. The totol Seismic coverage for this project is approximately 1400 feet. Lines A5 ond 85 ore situated on a knob composed almost entlrely of high velocity material - 10,ooO and 9500 ft/sec from 2 to 8 feet deep. Overlying this Volcanic material is a layer of similar moteriol, but slightly decomposed and fmctured, which has a velocity of boo0 to 6500 ft/sec. The Sedimentory - Volcanic contact occurs on line A5 between stations 1 and 2. The maximum velocity measured northeast of station 1 is 2500 ft/sec to a depth of 38 feet. The Volconics in this area dip steeply northeost. There is also a thin soil cover on the knob itself of up to 2 feet, however it is not continuous. Line C5 was run from the sedimentary areo, which is a mixture of sands, slits, and cloys, over the Volcanic material and bock into the sediments in order to determine the limits of the rock. These contacts were located approximately at stations 1.5 ond 7.5 on llne C5. Three to four velocity layers were mapped along this line. Northeast of station 1.5, the sedimentary velocity does not exceed 2500 ft/sec to a depth of 35 feet. At the other end of the line, southwest of station 7.5, another loyer is Indicated below the 2200 to 2700 ft/sec layer, that is, a stmto which has a velocity of 3500 to 3700 ft/sec and extends from a depth of 20 feet to o depth of 40 feet. Within these sedimentary boundaries the Volcanic material rises abruptly almost to the surface. The velocity of this material is from 8000 to 9088 ft/sec. Over- lying the high velocity materiol on both ends is a layer of decomposed and fmc- tured Volcanics with a velocity mnge of 5800 to 5100 ft/sec. The configuration of this layer is as shown on the velocity pmflle. Conclusions: High velocity material was located very near to the surface on lines A5 and 85, however a low velocity sedlmentory contact exists on the northeast end of the line. Line C5 indicates sedimentary contacts on both ends of the line with the high velocity Volcanics in between. The 5ooO ft/sec moteriol is marginal In terms of rlppability and should prove to be very hard ripping to light shooting prior to removal. Lines A-5 to C-5, Inclusive -2- September 26, 197(~ In terms of rippability, based on the capability of a D-9 Cot, the following schedule would apply: Velocity 0 to 2000 ft/sec 2ow to 5004 ft/sec 5000 to 5500 ft/sec Over 5500 ft/sec Exwvation Method Scraper Ripper Marginal Drill & Shoot -. - .- - - - - - - -. PHILIP HENKING BENTON PrlELIDENT Cl”lL ENWNEER BENTON ENGINEERING. INC. APPLIED 5011~ MECHlNlCS FOLINDA.TIONS 6749 EL C<JON BcJLlLFVARO SAN DIEGO CALIFORNIA 92,15 February 15, 1971 Roncho Lo Costa Route 1, Box 2550 Encinitas, Colifomio 920214 Subject: Project No. 70-4-l F Fifth Addendum to . . Pe ‘Is Investigation .~ Lo Cost0 Meadows Units 1 to 4, inclusive Svia Gentlemen: SAN DlELO 583 5654 LA Mb>, 469~565‘l Reference is mode to our report of June 15, 1970 some subject os obove,and subsequent addenda doted OS follows: July 7, 1970 which forwarded subsurface investigation on Lines A-2 to D-2, inclusive. September 4, 1970 which forwarded Drowing Nos. 29 ond 30. September 22, 1970 which forwarded subsurface investigation on Line A-4 to D4. November 20, 1970 which forwarded Drawing No. A - Slope Stability Analysis. , This is to formally forward the following subsurface investigations, each of which hove been hand delivered to Rick Engineering. Lines A5 to C5, inclusive, doted September 26, 1970 Lines A6 to D6, inclusive, dated October 7, 1970 Lines A7 to C7, inclusive, dated October 16, 1970 Lines A8 to D8, inclusive, dated October 28, 1970 Lines Al 1 to Dll, inclusive, doted February 4, 1971 T. FUNNEKOTTER REGISTERED GEOLOGIST CERTIFIED ENGINEERING GEOLOGIST P.O. BOX 575 ESCONDIDO, CALIFORNIA 92025 - - SUBSURFACE INVESTIGATION - - - - - LA COSTA MEADOWS LINES A-11 to D-11, INCLUSIVE PROJECT NO. 7%4-IF FEBRUARY 4, 1971 - LINES A-l 1 to D-l 1, INCLUSIVE - d -‘-. d 2 -5 -z 2 k -L I. . -0 i .:Fr Purpose: To evoluote subsurface conditions at two select areas in order to facilitate grading design by anticipating ony excavation problems that might exist. Method: Discussion: Refraction Seismograph - hammer impact method. Geologic reconnaissance. The areas investigated ore composed of volcanic moteriol - from ondesite to rhyolite. Four lines were investigated - All, Bll, Cl 1, and Dll which ore positioned as shown on the enclosed location plot. Total Seismic coverage is 1350 lineal feet. Lines Al 1 and Bll are in the first area and cross each other at right angles. In general, bath lines indicate comparable velocities in three layers. The uppermost layer is soil up to 8 feet thick and has a velocity range of 1400 to 1600 ft/sec. The middle layer of decomposed and fractured material has a velocity range of 3000 to 3500 ft/sec and extends from 12 feet to 40 feet deep. The lower layer is the porent rock with o velocity range of 8500 to 9000 ft/sec and was encountered as close as 12 feet from the surface. This material appears to dip north on line Bll and east on line Al 1 . Large blocks of hard material ore incorporated within the softer upper mantle. The second orea investigated (lines Cl 1 ond Dll) is considerably more complex. Four layers were mapped here - the soil layer (1400 to 1900 ft/sec), two de- composed and fractured layers (3000 to 3200 ft/sec and 5000 to 5200 ft/sec), and the underlying high velocity volcanic materiol (7600 to 9000 ft/sec). The high velocity material is from 4 feet to 30 feet deep. Most appears to overage approximately 15 feet deep. However, on added problem here is the presence of a considerable amount of marginal material with velocities of 5000 to 5200 ft/sec within a few feet of the surface. There appeors to be many hard knolls extending up into the softer mantle in this areo. The high velocity horizon is very uneven and rises and foils very rapidly within~short horizontal distances. Also, many large, hard blocks are common in this area. Conclusion: All lines encountered high velocity parent rock from depths of 6 feet to 40 feet. The configuration of this material is especially erratic in area hvo (lines Cl1 and Dll). It is also closer to the surface here. In addition, a considerable amount of marginal material was located here. This informo- tion points to the conclusion that in this area if substantial cuts are proposed, considerable difficulty can be anticipated. Lines A-l 1 ta D-l 1, inclusive -2- February 4, 1971 Conclusion: (Cont.) In terms of rippability, based on the performance of a D-9 Cot the following schedule would apply: Velocity (ft/sec) Excavation Method 0 to 2000 Scraper 2ooo to 5ooo Ripper 300 to 5500 Morginal Over 5500 Drill d Shoot - Submitted by (Signed) T. Funnekotter T. Funnekotter PH,LCP HENKING BENTON P.ES,DENT ClYlL ENGINEER BENTON ENGINEERING. INC. APPLIED SOIL MECHANICS - FOUND*T,ON* 5741 El CAJON BOVLEYARD SAN DIEGO. CALIFORNIA 92‘15 June 28, 1972 La Costa Land Company Costa Del Mar Road Ranch0 La Costa, California 92008 Subject: Praiect No. 70-lo-28D (Grading Permit L 3785) Final Report on an Diego, California Gentlemen: - - -1 -. This is to report the final resulk of tesk and observations made in order to inspect the comFoction of filled ground placed on certain areas of Lok 92 and 185 in La Costa Meadows Unit No. 1. The results of tests and observations made to%&t thecompaction of filled ground placed during the major grading of this subdivislon and special recommendations for construction on expansive soils were included in our interim report on this project dated October 12, 197i. This report includes the resulk of test Nos. 1377 to 1380, inclusive, taken in compacted filled ground placed on Lok 92 and 185. These fills were placed on April 24, 1972 and June 13, 1972. This report includes all test data and i&notion not previously reported and completes our final report on La Costa Meadows Unit No. 1. The approximate areas and depths of filled ground placed under our inspection in accordance w’ith the approved specifications are shown on the attached Drawing No. 1, entitled “Location of Compacted Filled Ground.” The grading plan used for the placement of filled ground was pre- pared by Rick Engineering Company and last revised January 29, 1971. The approximate locations at which test Nos. 1377 ta 1380, inclusive, were taken and the final test resutk were presented on page T-44, under the “Table of Test Resulk.” Test Nos. 1 to 1376, inclusive, were presented on pages T-l ta T-43, inclusive, of our previous report. The laboratary determinations of the maximum dry densities ond optimum moisture contenk of the major fill materials placed during this recent grading period are presented on page L-l under the “Lobora- tory Test Resul k.“ Test Nos. 1377 ta 1380, inclusive, reported herein, were taken on the dates indicated below: Test Number Date 1377 and 1378 April 24, 1972 1379 and 1380 June 13, 1972 --\ . . - f 1 - \ f - j Project NO. 70-lo-28D LaCosta Meadows Unit No. 1 -2- June 28, 1972 The final results of tests and observations indicate that the compacted filled ground has been placed at 90 percent of maximum dry density or greater. it hcrc been determined that the fill materials, compacted to 90 percent of the maximum dry density, have a safe bearing value of 1930 pounds per square foot for one foot wide continuous footings founded at a minimum depth and placed 5 feet or more inside the top of the compacted filled ground slopes. If footings are placed closer to the exposed slopes than 5 feet inside the top of compacted filled ground slopes, these should be deepened one foot below a 1 l/2 horizontal to 1 vertical line projected outward and downward from a point 5 feet horizontally inside the top of compacted filled ground slopes. Tesk indicate that the compacted filled ground is adequate to support the proposed wood frame dwellings without detrimental settlements. Critically expansive soils exist in the upper thnse feet below finished grade on Lok 92 and 185. Therefore the special design and precautions presented for Type “A” iok in our previous intx report dated October 12, 1971 are recommended for buildings constructed on these two iok. Respectfully submitted, BENTON ENGINEERING, INC. R. C . Remer Reviewed by Philip H. Beiton, Civil Engineer - Dlstr: (4) Addressee (1) La Costa Land Compony Attention: Mr. Burton L. Kmmer (1) Rick Engineering Company (2) San Diego County Building Inspection, Vista Office (1) San Diego County Engineering Department Attention: Mr. Joe Soveiia - RCR/PHB/ew - BENTON ENGlNEERING. INC. .~ -r - I - - - - - - PHlLlP “ENKING BENTON PIILIIDTHT ClVlL ENCINEEI BENTON ENGINEERING. INC. *PPLIE* 501L MECHANICS -- FO”No*TIONS 6741 EL CAJON BOULE”*RD s*N DIEGO. C*LIFORNI* 92115 June 28, 1972 sr* DiL.50 ,dJ.565d L. HCLA C69~5654 La Costa Land Company Costa Dei Mar Road Ranch0 La Costa, California 92008 Subject: Project No. 70-lo-28D (Grading Permit L 3785) Final Report on CompactecWllsb round /------ =-Y Lok 92 and 185 of - ‘SaCasta-Mwdodo . 1 an Diego, California 4 p_l;- J Gentlemen: fe‘ This is to report the final resuik of tesk and observations mode in order to inspect the compaction of filled ground placed on certain areas of Lok 92 and 185 in La Costa Meadows Unit No. 1. The resulk of tesk and observations made to%& thecompaction of filled ground placed during the malor grading of this subdivision and special recommendations for construction on expansive soils were included in our interim report on this project dated October 12, 197i. This report includes the results of test Nos. 1377 to 1380, inclusive, taken in compacted filled ground placed on Lok 92 and 185. These fills were placed on April 24, 1972 and June 13, 1972. This report includes all test data and information not previously reported and completes our final report on La Costa Meadows Unit No. 1, The approximate areas and depths of filled ground placed under our inspection in accordance w’ith the approved specifications are shown on the attached Drawing No. 1, entitled “Location of Compacted Filled Gmund.” The grading plan used for the placement of filled ground was pre- pared by Rick Engineering Company and last revised January 29, 1971. The approximate locations at which test Nos. 1377 to 1380, inclusive, were taken and the final test resulk were presented on page T-44, under the “Table of Test Resuik.” Test Nos. 1 to 1376, inclusive, were presented on page T-l to T-43, inclusive, of our previous report. The laboratory determinations of the maximum dry densities and optimum moisture contents of the major fill materials placed during this recent grading period are presented on page L-l under the “Labora- tory Test Resul k.” Test Nos. 1377 to 1380, inclusive, reported herein, were taken on the dates indicated below: Test Number Date 1377 and 1378 April 24, 1972 1379 and 1380 June 13, 1972 ..- -, -_ -[ Project NO. 70-l O-28D La Costa Meadows Unit No. 1 -2- June 28, 1972 The final resui k of tesk and observations indicate that the compacted filled ground has been placed at 90 percent of maximum dry density or greater. it has been determined that the fill materials, compacted to 90 percent of the maximum dry density, have a safe bearing value of 1930 pounds per square foot for one foot wide continuous footings founded at a minimum depth and placed 5 feet or more inside the top of the compacted filled ground slopes. if footings are placed closer ta the exposed slopes than 5 feet inside the top of compacted filled ground slopes, these should be deepened one foot below a 1 l/2 horizontal to 1 vertical line projected outward and downward from a point 5 feet horizontally inside the top of compacted filled ground slopes. Tests indicate that the compacted filled ground is adequate to support the proposed wood frame dwellings without detrimental settlements. Critically expansive soils exist in the upper three feet below finished grade on Lok 92 and 185. Therefore the special design and precautions presented for Type “A” lok in our previous intz report dated October 12, 1971 are recommended for buildings constructed on these two iok. Respectfully submitted, BENTON ENGINEERING, INC. Brz&?z&em R. C. Remer Reviewed by Philip H. Benton, Civil Engineer Dktr: (4) Addressee (1) La Costa Land Company Attention: Mr. Burton L. Kramer (1) Rick Engineering Company (2) San Diego County Building Inspection, Vista Office (1) San Diego County Engineering Department Attention: hlr. Joe Sovelia RCR/PHB/ew sENTON ENGINEERING. INC. BENTON ENGINEERING. INC. -r -1 Y - - - - .- &PPLIED 501L MECHANICS - FOUND*TIOMS 6741 EL CA,ON BcJ”LS”*RD *AN DIEGO. C*LIFORNI* 92115 PH,L,P HENKING BENTON PICSIDCHT C3”IL L*GINcErl La Costa Land Company Costa Dal Mar Road Rancho La Costa, California 92008 June 28, 1972 S.” OIECO 5*?-565a L. MLS. ‘b9.5654 Subject: Project No. 70-lO-28D (Groding Permit L 3785) Final Report on Compacted-EiilecL round /---- v Lok 92 and If35 of -- ‘- LbCs to-hhaddo . 1 an Diego, Califomio 4 /.* J Gentlemen: fl,” This is to report the final results of tesk and observatibns made in order to inspect the compaction of filled ground placed on certain areas of Lok 92 and 185 in La Costa Meadaws Unit No. 1. The results of tesk and observations mode to%&t thcvaction of filled ground placed during the maior grading of this subdivision and special recommendations for construction an evansive soils were included in our interim report on this project dated October 12, 1971. This report includes the resuik of test Nos. 1377 ta 1380, inclusive, taken in compacted filled ground placed on Lok 92 and 185. These fills were placed on April 24, 1972 and June 13, 1972. This report includes ail test data and information not previously reported and completes our final report on La Costa Meadows Unit No. 1. The approximate areas and depths of filled ground placed under our inspection in accordance with the approved specifications are shown on the attached Drawing No. 1, entitled “Location of Compacted Filled Ground.” The grading plan used for the placement of filled ground was pre- pared by Rick Engineering Company and last revised January 29, 1971. The approximate locations at which test Nos. 1377 ta 1380, inclusive, were taken and the final test resuik were presented on page T-44, under the “Table of Test Resuik.” Test Nos. 1 to 1376, inclusive, were presented on pages T-l ta T-43, inclusive, of our previous report. The laboratory determinations of the maximum dry densities and optimum moisture contenk of the maior fill materials placed during this recent grading period are presented on page L-l under the “Labora- tory Test Resutk.” Test Nos. 1377 to 1380, inclusive, reported herein, were taken on the dates indicated below: Test Number Date 1377 and 1378 April 24, 1972 1379 and 1380 June 13, 1972 - -~ ..- -, - i Project NO. 70-i O-28D La Costa Meadow Unit No. 1 -2- June 28, 1972 The final resui k of tesk and observations indicate that the compacted filled ground has been placed at 90 percent of maximum dry density or greater. it hm been determined that the fill materials, compacted to 90 percent of the maximum dry density, have a safe bearing value of 1930 pounds per square fgot for one foot wide continuous footings founded at a minimum depth and placed 5 feet or more inside the top of the compacted filled ground slopes. If footings are placed closer ta the exposed slopes than 5 feet inside the top of compacted filled gmund slopes, these should be deepened one foot below a 1 l/2 horizontal to 1 vertical line projected outward and downward from a point 5 feet horizontally inside the top of compacted filled ground slopes. Tests indicate that the compacted filled ground is adequate to support the proposed wocd frame dwellings without detrimental settlements. Critically expansive soils exist in the upper three fset below ftnished grade on Lok 92 and 185. Therefore the special design and precautions presented for Type “A” iok in our previous intx report dated October 12, 1971 are recommended for buildings constructed on these twa iok. Respectfully submitted, BENTON ENGINEERING, INC. BY z&? R. C. Remer Reviewed by Philip H. Be&on, Civil Engineer Dlstr: (4) Addressee (1) La Costa Land Company Attention: Mr. Burton L. Kramer (1) Rick Engineering Company (2) San Diego County Building Inspection, Vista Office (1) San Diego County Engineering Department Attention: hIr. Joe Sovella - - -~ RCR/PHB/ew eENTON ENGINEERING. INC. - - PHIL,? HENKING BENTON PRESIDENT. CIYIL ENGtUEFI BENTON ENGINEERING. INC. APPLIED 501L MECHANICS ~- FOUNDATIONS 6741 EL CAJON BOULEVARD *AN OIEGO. CILIFQRNIA 92115 June 28, 1972 La Costa Land Company Costa Dei Mar Road Ranch0 La Casta, California 92008 Subject: Project No, 70-10-28D (Grading Permit L 3785) Final Report on Compacted-Filled-Ground 92andi85of ‘\ -‘.i’-li- J Gentlemen: 43 p6 This is ta report the final resuik of tesk and observations mode in order to inspect the compaction of filled ground placed on certain areas of Lok 92 and 185 in La Costa Meadows Unit No. 1. The resuik of tests and observations made to%&t thzpaction of filled ground placed during the maior grading of this subdivision and special recommendations for construction on expansive soils were included in our interim report on this project dated October 12, 1971. This report includes the resuik of test Nos. 1377 ta 1380, inclusive, taken in compacted filled ground placed on Lok 92 and 185. These fills were placed on April 24, 1972 and June 13, 1972. This report includes all test data and information not previously reported and completes our final report on La Costa Meadows Unit No. 1. The approximate areas and depths of filled ground placed under our inspection in accordance with the approved specifications are shown on the attached Drawing No. 1, entitled “Location of Compacted Filled Ground.” The grading plan used for the placement of filled ground was pre- pared by Rick Engineering Company and last revised January 29, 1971. The approximate locations at which test Nos. 1377 ta 1380, inclusive, were taken and the final test resuik were presented on page T-44, under the “Table of Test Resuik.” Test Nos. 1 to 1376, inclusive, were presented on pages T-l to T-43, inclusive, of our previous report. The laboratory determinations of the maximum dv densities and optimum moisture contents of the major fill materials placed during this recent grading period are presented on page L-l under the “Labora- tory Test Resuik.” Test Nos. 1377 to 1380, inclusive, reported herein, were taken on the dates indicated below: Test Number Date 1377 and 1378 April 24, 1972 1379 and 1380 June 13, 1972 - Project NO. 70-10-280 -2- June 28, 1972 La Costa Meadows Unit No. 1 The final resulk of tests and observations indicate that the compacted filled ground has been placed at 90 percent of maximum dry density or greater. It has been determined that the fill materials, compacted to 90 percent of the maximum dry density, have a safe bearing value of 1930 pounds per square foot for one Foot wide continuous footings founded at a minimum depth and placed 5 feet or more inside the top of the compacted filled ground slopes. If footings are placed closer to the exposed slopes than 5 feet inside the top of compacted filled ground slopes, these should be deepened one foot below a 1 l/2 horizontal to 1 vertical line projected outward and downward from a point 5 feet horizontally inside the top of compacted filled ground slopes. Tesk Indicate that the compacted filled ground is adequate to support the proposed wood frame dwellings without detrimental settlements. Critically expansive soils exist in the upper three feet below finished grade on Lok 92 and 185. Therefore the special design and precautions presented for Type “A” lok in our previous intx report dated October 12, 1971 ore recommended for buildings constructed on these two iok. Respectful I y submitted, ; BENTON ENGINEERING, INC. - R. C. Remer - i Reviewed by Philip H. Benton, Civil Engineer - Dfstr: (4) Addressee (1) La Costa Land Company Attention: Mr. Burton 1.. Kramer (1) Rick Engineering Compony (2) San Diego County Building InspectIon, Visto Office (1) San Diego County Engineering Department Attention: b!r. Joe Sovello - RCR/PHB/ew BENTON ENGINEERING. INC. -h ,- - - - PHlLlP HENKING BENTON *.FSIOLHT. ClYlL ENGINLLI BENTON ENGINEERING. INC. APPLIED SOIL MECHANICS .- FOUNDLITIONS 6741 EL CI,ON BOULEYLiRD S&N DIEGO. CALIFORLNIA 91115 June 28, 1972 *.r DlECO 583.5654 ‘1 1LI. 469~565A La Cost0 Lond Company Costa Del Mar Road Ranch0 La Cc&a, California 92008 Subject: Project No. 70-10-280 (Grading Permit L 3785) Final Report on o. , / k”./ J Gentlemen: P’ J-8 This is to report the final resulk of tesk and observatibns mode in order to inspect the compaction of filled ground placed on certain ares of Lok 92 and 185 in La Costa Meadows Unit No. 1. The resufk of tesk and observations mode to-t thcompoction of filled ground placed during the major grading of this subdivision and special recommendations for construction on expansive soils were included in our interim report on this project dated October 12, 1971. This report includes the resulk of test Nos. 1377 to 1380, inclusive, token in compacted filled ground placed on Lok 92 and 185. These fills were placed on April 24, 1972 and June 13, 1972. This report includes all test doto and informotion not previously reported ond completes our final report on La Costa Meadows Unit No. 1. The approximate areas and depths of filled ground placed under our inspection in accordance with the approved specifications are shown on the attached Drawing No. 1, entitled “Location of Compacted Filled Ground.” The grading plan used for the placement of filled ground was pre- pared by Rick Engineering Company and last revised January 29, 1971. The approximate locations at which test Nos. 1377 to 1380, inclusive, were taken and the final test resuik were presented on page T-44, under the “Table of Test Resulk.” Test Nos. 1 to 1376, inclusive, were presented on pages T-l ta T-43, inclusive, of our previous report. The laboratory determinations of the maximum dry densities and optimum moisture contenk of the major fill moterials placed during this recent grading period are presented on page L-l under the “Labora- tory Test Resul k. ” Test Nos. 1377 to 1380, inclusive, reported herein, were token on the dates indicated below: Test Number Date 1377 and 1378 April 24, 1972 1379 and 1380 June 13, 1972 - Project No. 70-l O-280 -2- June 28, 1972 La Costa Meadows Unit No. 1 - 7 -, ~.. ,~. The final resulk of tests and obselvatlons indicate that the compacted filled ground has been placed at 90 percent of maximum dry density or greater. It has been determined that the fill materials, compacted to 90 percent of the maximum dry density, have o safe bearing value of 1930 pounds per square foot for one foot wide continuous footings founded at a minimum depth and placed 5 feet or more inside the top of the compacted filled ground slopes. If footings are placed closer to the exposed slopes than 5 feet inside the top of compacted filled ground slopes, these should be deepened one foot below a 1 l/2 horizontal to 1 vertical line projected outward and downward from a point 5 feet horizontally inside the top of compacted filled ground slopes. Tesk Indicate that the compacted filled ground is adequate to support the proposed wood frame dwellings without detrimental settlements. -j Critically expansive soils exist in the upper three feet below finished grade on Le and 185. Therefore the special design and precautions presented for Typa “A” lok in our previous intx report dated October 12, 1971 are recommended for buildings constructed on these two lots. Respectfully submitted, BENTON ENGINEERING, INC. R. C. Remer - Reviewed by Philip H. Be&ton, Civil Engineer - - Distr: (4) Addressee (1) La Costa Land Company Attention: Mr. Burton L. Kramer (1) Rich Engineering Company (2) San Diego County Building Inspection, Vista Office (1) San Diego County Engineering Department Attention: hlr. Joe Sovella RCR/PHB/ew BENTON ENGINEERING. INC. - -h I - Y - - -- I - - PHlLlP HENKING BENTON PIIKSIOLHT ClVlL L*IGINEEII BENTON ENGINEERING. INC. APPLIED SOlI. MECHANICS -- FO”ND*T,ON* 6741 EL c*,oLI BOULEVARD SAN DIEGO. CALIFORNIA 9t115 June 28, 1972 5.” DlLCO 5tl)3-565G L. YLb. 069~5554 La Costa Land Company Costa Del Mar Rood Ranch0 La Costa, California 92008 Subject: Project No. 70-10-280 (Grading Permit L 3785) Final Report on Compacter-FilledGround Gentlemen: Thb is to report the final resul k of tesk and observations made in order to inspect the canpaction of filled ground placed on certain areas of Lok 92 and 185 in La Costa Meadows Unit No. 1. The resulk of tests and observations made to%&t th=paction of filled ground placed during the moior grading of this subdivision and special recommendations for construction on expansive soils were included in our interim report on this project doted October 12, 197i. This report includes the resulk of test Nos. 1377 to 1380, inclusive, taken in compacted filled ground placed on Lok 92 and 185. These fills were placed on April 24, 1972 and June 13, 1972. This report includes all test data and information not previously reported and completes our final report on La Costa Meadows Unit No. 1. The approximate areas and depths of filled ground placed under our inspection in accordance with the approved specifications are shown on the attached Drawing No. 1, entitled “Location of Compacted Filled Ground.” The grading plon used for the placement of filled ground was pre- pared by Rick Engineering Company and last revised January 29, 1971. The approximote locations at which test NOS. 1377 b 1380, inclusive, were taken and the final test resulk were presented on page T-44, under the “Table of Test Resulk.‘! Test Nos. 1 to 1376, inclusive, were presented an pages T-l to T-43, inclusive, of our previous report. The laboratory determinations of the maximum dry densities ond optimum moisture contents of the maior fill materials placed during this recent grading period are presented on page L-l under the “Lobora- tory Test Resulk.” Test Nos. 1377 to 1380, inclusive, reported herein, were taken on the dates indicated below: Test Number Date i 37/ and 1378 April 24, 1972 1379 and 1380 June 13, 1972 - Project NO. 70-10-280 -2- June 28, 1972 Lo-Costa Meadows Unit No. 1 I- -, The final resulk of task and observations indicate that the compacted filled ground has been placed at 90 percent of moximum dry density or greater. It hce been determined that the fill materials, compacted to 90 percent of the maximum dry density, have a safe bearing value of 1930 pounds per square foot for one foot wide continuous footings founded at a minimum depth and placed 5 feet or more inside the top of the compacted filled ground slopes. If footings are placed closer to the exposed slopes than 5 feet inside the top of compacted filled ground slopes, these should be deepened one foot below a 1 l/2 horizontal to 1 vertical line projected outward and downward from a point 5 feet horizontally inside the top of compacted filled ground slopes. Tests indicate that the compacted filled ground is adequote to support the proposed wood frame dwellings without detrimental settlements. -; f Critically exponsive soils exist in the upper three feet below finished grade on Lots 92 and 185. Therefore the special design and precautions presented for Type “A” lob in our previous tntx report dated October 12, 1971 are recommended for buildings constructed on these hva lok. -. i Respectfully submitted, -i 1 BENTON ENGINEERING, INC. -. R. C. Remer ..- Reviewed by Philip H. Benton, Civil Engineer Distr: (4) Addressee (1) La Costa Land Company Attention: Mr. Burton L. Kramer (1) Rick Engineering Company (2) San Diego County Building Inspectton, Vista Office (1) San Diego County Engineering Department Attention: hti. Joe Sovello RCR/PHB/ew BENTON ENGINEERING. INC