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637, Construct new SFR with garages, Studies & Reports/Dist: Office 12.02 County of Los Angeles Department of Public Works DISTRIBUTION GEOTECHNICAL AND MATERIALS ENGINEERING DIVISION __ _ . - 2Dist. Office Sheet 1 of 2 - GEOLOGIC REVIEW SHEET . 1 Geologist 900 So. Fremont Ave., Alhambra, CA 91803 1 Soils Engineer TEL. (626) 458-4925 1 GMED File Grading Section 1 Inspector 1 Engineer/Arch. Tract 30345 Lot 2 Parent Tract Location City of Rolling Hills Site Address #1 Sagebrush Lane (#13 Upper Blackwater Canyon) Geologist Gale Hunt Developer/Owner Fan Soils Engineer Dale Hinkle, P.E., Inc. Engineer/Arch. Frank Politeo Processing Date on Grading Plans 11/10/04 Grading P.C. No. 0107160002 For: Grading (4650 c.y.) for future SFR (14,000 ft 2) Building P.C. No. (ref. 0408110068) Geologic Reports Dated Keene: 7/11/03, 1/13/01 Soils Engineering Reports Dated T.I.N Engineering: 8/01/03, 2/07/01 (000570) Geology and Soils Engineering Report Dated 10/11/04, 7/08/04, 3/24/04 Action: X Plan is recommended for approval from a geologic standpoint, subject to conditions below. _Plan is not recommended for approval for reasons below. Remarks/Conditions: 1. In -grading inspections must be made by the consulting geologist and soils engineer_ Monthly in -grading inspection reports must be submitted directly to the Geology and Soils Section by the consultants. • Rough grading must be approved by a final engineering geology and soils engineering report. An As -Built Geologic Map must be included in the final geology report. Provide a final report statement that verifies work was done in accordance with report recommendations and code provisions (Section 3318.1). The final report(s) must be submitted to the Geotechnical and Materials Engineering Division for review and approval. Foundation and wall excavations must be inspected and approved by the consulting geologist and soils engineer prior to the placing of steel or concrete. - 2. The Soils Engineering review dated (2(0/0 4 Is attached. Prepared by c 'Karin Vazq P:1Gmepub\Geology Review\Fomis\Foim08.doc 6/12/03 Reviewed by Date December 9, 2004 COUNTY OF LOS ANGELES_ DEPARTMENT OF PUBLIC WORKS • GEOTECHNICAL AND MATERIALS ENGINEERING DIVISION SOILS ENGINEERING REVIEW SHEET Address: 900 S. Fremont Ave., Alhambra, CA 91803 District Office 12.02 Telephone: • (626) 458-4925 Job Number B372001 Fax: (626) 458-4913 Sheet 1 of 1 DISTRIBUTION: Single Family Residence and Pile -Supported Retaining Walls _ Drainage _ Grading Location 1 Sagebrush Lane (13 Upper Blackwater), City of Rolling Hills - 1 Geo/Soils Central File Developer/Owner Fan 2 District Engineer Engineer/Architect Politeo & Chong . Geologist Soils Engineer Dale Hinkle, P.E. Inc. " 1 Soils Engineer Geologist Dale Hinkle, P.E. Inc. (Gail S. Hunt) 1 Engineer/Architect Grading Plan Check No. 0107160002 Review of: Grading Plan Dated By Processing Center 11/10/04 Geotechnical Reports Dated 10/11/04, 7/8/04, 3/24/04 Soils Engineering Reports By T.I.N. Engineering Dated 8/1/03, 2/7/01 Geologic Reports By Art Keene Dated 7/11/03, 1/13/01 Percolation Test Report By C&M Partnership Dated 3/30/04 Previous review sheet dated 10/27/04 ACTION: Plan is recommended for approval, subject to the condition below: REMARKS: Submit a rough grading report to the Soils Section for verification that the completed work complies with County codes and policies. NOTE(S) TO THE PLAN CHECKER/BUILDING AND SAFETY DISTRICT ENGINEER: A. ONLY THE SOILS AND FOUNDATION RECOMMENDATIONS DEPICTED ON THE PLANS ARE APPROVED. B. ON -SITE SOILS ARE CORROSIVE TO FERROUS METALS AND HAVE A VERY HIGH EXPANSION POTENTIAL. C. THE PLANS SHOW ALL FOOTINGS FOR THE PROPOSED RESIDENCE WILL BE EMBEDDED INTO BEDROCK. THIS MAY REQUIRE DEEPENED FOOTINGS, POSSIBLY EVEN WITHIN THE BASEMENT PORTION OF THE PROPOSED STRUCTURE. D. DETACHED STRUCTURES SHALL BE UNIFORMLY FOUNDED UPON COMPETENT DENSE NATIVE BEARING MATERIALS. E. PER THE SOILS ENGINEER, THE HIGHLY EXPANSIVE ON -SITE SOILS SHALL NOT BE PERMITTED IN WALL BACKFILL MATERIALS. repared by Reviewed by Brian D. Smith Gan Lem Date 12/6/04 NOTICE: Public safety, relative to geotechnical subsurface exploration, shall be provided in accordance with current codes for excavations, inclusive of the Los Angeles County Code, Chapter 11.48, and the State of California, Title 8, Construction Safety Orders. P:\gmepub\Soils Review\Smith\1 Sagebrush Lane, City of Rolling Hills, GP -A 6.doc Sent By: MATERIALS ENGINEERING; 626 458 4913; Jun-7-04 2:18PM; Page 1 • Dist. Office 12.02 Co y of Los Angeles Post -it• Fax Note 01 (0Bte4'?/b (pages► GEOTECHNiCAL AND MA To \/p f t.,,,7� From 6, ‘ t-o.,., Sheet 1 of 2 GEOLOGI Co./Dept. 1co. 900 So. Fremont r Phone ft Phone fi TEL. ( #(.� Fax (Ste) 31Y)— )2 2 Fax a Tract 30345 Lot 2 Parent Tract Location City of Rolling Hills Site Address #13 Upper Blackwater Canyon (1 Sagebrush Lane) Geologist Gale Hunt Developer/Owner Fan Soils Engineer Dale Hinkle, P.E.. Inc. Engineer/Arch. Frank Politeo Processing Center Date 4/01/04 Grading P.C. No. 0107160002 For: Grading (4650 c.y.) for future SFR (14,000 ft.2) Building P.C. No. N/A • Geologic Reports Dated 7/11/03, 1/13/01 Soils Engineering Reports Dated 8/01/03, 2/07/01 (000570) Geology and Soils Engineering Report Dated 3124/04 Action: Plan is not recommended for approval for reasons below. Remarks/Conditions: i Mf I91T ICel /Ai i:i i. 1. The consultant must show all structural data on the geologic map and cross -sections. including the current and previous geologic consultants work. This data must include the following: bedding attitudes, contact orientation, joint/fracture orientation, slide plane orientation, striae/slickenside orientation, fault orientation, corresponding depths, etc. 2. Based on USGS Professional Paper 207 (Woodring, Bramlette, and Kew, 1946), terrace deposits do not undedy the site. It is strongly suggested that the consulting geologist review the descriptions of the mapped terrace deposits, which do not appear to correspond to the material descriptions provided for the subject site, i.e. they lack the defining elements that are identified within the mapped terrace deposits. Please provide an explanation, based on the data presented, as to the origin of the 30-feet of colluvial materials. 3. The limits of the pre -historic landslide for the subject site must be determined. in making this determination, consider the following: a. On page 5 of the current report the consultant states that a possible landslide or fault in Boring 5 @ 50' was observed and goes on to state that the "old landslide feature could exist" under the building site. The consultant must provide a definitive conclusion based on the subsurface data obtained thus far. b. The current geologist identified a 3-inch thick slide plane in Boring B-41s at 61-feet and described stickensided bentonitic shale to 71-feet, indicating that the limits of the landslide extend to at least the vicinity of B-41s. c. Trench No 7, logged by Keene, strongly suggests the presence of a head scarp, which appears to correspond to Cleveland (1976). 4. Revise the geologic cross -sections to include the subsurface detail available for the subject site and 5 & 6 Sagebrush Lane. 5. Please clearly indicate on the boring logs for the subject site where the blue -black claystone was encountered, which was coincident with the slide plan at 5 & 6 Sagebrush. Please also indicate the depth at which coring was required for all logs. It was Indicated that caving/collapse occurred in B-4 (percolation test location), please indicate depth and interval affected. (It is important for the consultant to note that the Geology Section did not necessarily accept the location of the eastern limits of the landslide presented in the reports for 5 & 6 Sagebrush and during the review for these properties it was determined that the "shorter" configuration was more critical for the design of the buttress at 5 & 6 Sagebrush). 6. On page 7 of the current report the consultants indicate that "water appears to flow in joints in the claystone to eventually reach Sepulveda Canyon,' indicating that daylighting of effluent is anticipated. The consultant must demonstrate that the effluent for the proposed seepage pit capacity will not Influence the slide plane when the limits of the landslide are conclusively determined. Data must be provided that addresses the possible adverse impact of the private sewage disposal system relative to site stability and adjacent properties. including the buttress at 5 & 6 Sagebrush Lane. (Note: Rough grading of the buttress fill at 5 & 6 Sagebrush Lane has not been approved by the Geology and Soils Sections). Discuss the path of migration of effluent and whether daylighting of the effluent will occur. Stability calculations must consider the effect on:groundwater. Show on geologic cross section(s) the anticipated path and saturation from the effluent based on hydrogeology of the site. (continued on next sheet) Sent By: MATERIALS ENGINEERING; 626 458 4913; Jun-7-04 2:19PM; Page 2/4 • Sheet 2 of 2 7. The consulting engineering geologist and soils engineer must clearly state that the proposed grading and future structures will be free from landsllding, settlement, and slippage and will not adversely impact offsite properties. (Note: this statement falls under Section 111 of the 2002 Los Angeles County Building Code). 8. All recommendations of the consulting geologist and soils engineer must be incorporated into the design orshown as notes on the plans. • 9, The plan must be specifically approved by the consultant geologist and soils engineer by manual, original signatures and dates on each sheet prior to approval by the Geology Section. Submit two (2) sets for review. 10. Add the following as notes to the plan: In -grading inspections must be made by the consulting geologist and soils engineer. Monthly in -grading inspection reports must be submitted directly to the Geology and Soils Section by the consultants. Rough grading must be approved by a final engineering geology and soils engineering report. An As -Built Geologic Map must be included in the final geology report. Provide a final report statement that verifies work was done in accordance with report recommendations and code provisions (Section 3318.1). The final report(s) must be submitted to the Geotechnical and Materials Engineering Division for review and approval. Foundation and wall excavations must be inspected and approved by the consulting geologist and soils engineer prior to the placing of steel or concrete. 11. Show all proposed corrective measures (buttresses, stability fills, deep removals, etc.) on the plan. 12, The Soils Engineering review dated if i $101-4 Is attached. Prepared by c.� Karin Vazq P:1Gmepub\Geology RenewTonns'FOrmO©.doe .--Reviewed by Date May 5, 2004 Sent By: MATERIALS ENGINEERING; 626 458 4913; • Jun-7-04 2:19PM; Page 3/4 • Address: Telephone: Fax: Review No. 3 COUNTY OF LOS ANGELES DEPARTMENT OF PUBLIC WORKS GEOTECHNICAL AND MATERIALS ENGINEERING DIVISION SOILS ENGINEERING REVIEW SHEET 900 S. Fremont Ave. Alhambra, CA 91803 (626) 458-4925 (626) 458-4913 Single Family Residence and Pile -Supported Retaining Walls Tract 30345 Lot 2 Location 13 Ueoer Blackwater f 1 Sagebrush) . City of Rollin(' Hills Developer/Owner Fan Engineer/Architect Polite(' & Chong Soils Engineer Dale Hinkle. P.E. Inc. Geologist Same as above Grading Plan Check No. 0) 07160002 Review of: Grading Plan Dated By Processing Center 5/5/04 Soils Engineering and Geologic Report Dated 3/24/04 Soils Engineering Reports By T.I.N. Engineering Dated 8/1/03 and 2/7/01 Geologic Reports By Art Keene Dated 7/11/03 and 1/13/01 Percolation Test Report By C&M Partnership Dated 3130/04 Previous review sheet dated: 10/27/03 ACTION: Plan is not recommended for approval. District Office 12.02 Job No. B372001 Sheet 1 of 2 DISTRIBUTION: Drainage __ Grading 1 Geo/Soils Central File 2 District Engineer 1 Geologist 1 Soils Engineer 1 Engineer/Architect REMARKS: 1. Requirements of the Geology Section are attached. Additional slope stability analysis may be required when the geology of the site is conclusively determined. 2. Stability analyses presented in the 3/24/04 report utilized average shear strength parameters. Provide additional stability analyses utilizing the weakest shear strength parameters to substantiate that the slopes will have adequate factors of safety. Recommend mitigation if factors of safety are below County minimum standards. 3. Verify the pile embedment depth of the piles for the proposed pile -supported retaining walls when the limits and depth of the landslide at this site is conclusively determined. If the proposed walls are within or downstope of the landslide, then the walls may be subject to additional surcharge from the landslide. If so, provide slope stability analysis as part of the proposed soldier piles design in order to determine the additional resisting lateral force required to bring the static factor of safety to a minimum 1.50. Recommend revised soldier pile embedment depths, pile spacing, etc. as necessary. 4. Page 7 of the 3/24/04 report states that water seeps out of joints in the claystone and eventually discharge in Sepulveda Canyon, which suggest a potential hydraulic connection between the points of effluent discharge to the canyon downslope of the site. Therefore, discuss the path of migration of the effluent and whether ponding or daylighting of the effluent will occur, considering the above. Also, provide data on the possible adverse impact of the private sewage disposal system(s) relative to site stability and adjacent properties, including the as -built buttresses at 5 & 6 Sagebrush. Stability calculations must consider the effect of ponding/perched groundwater. 5. The 3/24/04 report recommends an Equivalent Fluid Pressure (EFP) of 42 pcf be used for the design of retaining walls for level backfill condition and for walls that will be backfilled with granular soils. However, an EFP of only 45 pcf is recommended for the design of retaining walls for level backfill condition and for walls that will be backfilled with on -site, highly expansive soils. Verify and recommend revised EFP's for walls that will be backfilled with on - site soils, considering that on -site soils have an Expansion Index of 185. Sent By: MATERIALS ENGINEERING; 626 458 4913; Jun-7-04 2:20PM; Page 4/4 • i.. • COUNTY OF LOS ANGELES DEPARTMENT OF PUBLIC WORKS GEOTECHNICAL AND MATERIALS ENGINEERING DIVISION SOILS ENGINEERING REVIEW SHEET Grading Plan Check No. 0107160002 REMARKS (CONT) Sheet 2 of 2 6. The 111 statement provided in the 3/24/04 report is incomplete. Indicate whether the proposed building site/grading constriction will be safe against hazard from future landsliding, settlement or slippage and whether the proposed building or grading construction will have on the geologic stability of property outside of the building site. Provide a revised 111 statement as necessary. 7. Show the following on the grading plans: a. Approximate limits and depth of removal and recompaction of slide debris/unsuitable soils. b. Grading required for construction of buttress/stabilization fills, as necessary. c. Detail of keying and benching for placement of fill over slopes steeper than 5:1 gradient. d. Location of private sewage disposal system(s). e. Revised pile:embedment depths, as necessary. f. All standard notes regarding fill compaction and soil density testing requirements g. All recommended mitigative measures of the sails engineer. 8, The Soils Engineer Of record must review the grading plans and sign and stamp the plans in verification of his recommendations. Original manual signature and wet stamp are required. 9. Submit two sets of grading plans to the Soils Section for verification of compliance with County codes and policies. 10. Include a copy of this review sheet with your response. NOTE(S) TO THE PLAN CHECKER/BUILDING AND SAFETY DISTRICT ENGINEER: A. ON -SITE SOILS ARE CORROSIVE TO FERROUS METALS AND HAVE A VERY HIGH EXPANSION POTENTIAL. B. PER THE SOILS ENGINEER, THE LOWER TIER RETAINING WALLS SHALL BE DESIGNED FOR AN ADDITIONAL 4.7 KIPS/LINEAR FOOT OF WALL: OR AN EQUIVALENT FLUID PRESSURE (EFP) OF 376 PCF FOR A 5 FEET HIGH WALL. C. THE PLANS SHOW ALL FOOTINGS FOR THE PROPOSED RESIDENCE WILL BE EMBEDDED INTO BEDROCK. THIS MAY REQUIRED DEEPENED FOOTINGS, POSSIBLY EVEN WITHIN THE BASEMENT PORTION OF THE PROPOSED STRUCTURE. • • • • repared by Gar1i Lem NOTICE: Public safety, relative to eeotechnicat subsurface exploration, shall be provided In accordance with current codes for excavations, Inclusive of the Los Angeles County Code, Chapter 11.48, and the State of California, Title 8, Construction Safety Orders. Date 5/18/04 Ganr.13-blackwater Sent By: MATERIALS ENGINEERING; 626 458 4913; } I Sheet 1 of 2 REVIEWER CALLING HOURS 8-9 a.m. & 3-4 p.m. Man,-Thurs. Jan-22-02 4:59PM; Page 1 Cou-••Los Angeles Department of Public We ' 411 LAND DEVELOPMENT DIVISION GEOLOGIC REVIEW SHEET 900 S. Fremont Ave,, Alhambra, CA 91803 TEL. (626) 458-4925 Tract/PM TR 30345 Parent Tract Site Address #13 Blackwater Canyon Geologist Art Keene Soils Engineer TIN Engineering Lot(s) 2 Location Rolling Hills / 5 f . h ►- r J, ®.t►_., I.e.... Developer/Owner Tony Fan Engineer/Arch. Politeo & Chong Review of: Grading P.C. No. 0107160002 For: SFR Geologic Report(s) Dated 1/13101 Soils Engineering Reports) Dated 2/7/01 Action: Plan is not recommended for approval for reasons below. 1 Dist. Office 12.02 F X NF DISTRIBUTION Dist. Office 1 Geologist 1 Soils Engr. 1 Section File _ Grading Sect. 1 Proc. Ctr. Remarks/Conditions: 1. A significant amount of data has been collected in the area that has not been incorporated into a geologic map, geologic cross sections, findings, conclusions and recommendations. Please review the files for Tract 30345 and properties along Blackwater Canyon Road and incorporate data. 2. An active landslide exists just downhill of the subject property. Provide this office with a geologic map and a whole series of geologic cross sections that depict the regional geologic conditions. It must be strongly noted that there Is a tremendous about of geologic data available for the lots 3 and 4 and the subject tract. All of this data must be incorporated into the geotechnlcal analysis of the subject property. Cross sections and geologic map must depict the entire area between Sepulveda Canyon to the ridge above Blackwater Canyon Road. 3. Any slope stability analyses must consider the shear strength data obtained from the active landslide and not utilize the active landslide mass in the analyses. Utilize geologic cross sections prepared by the consulting geologist (see item 2 above). The slope stability analysis must take into account the strength values obtained by the geotechnlcal consultants studying the active landslide west of the subject property and incorporate the regional groundwater and effluent plumes generated _by the existing and proposed seepage pits. 4. The limits of the active landsllding. inactive old landslide mass and in -place bedrock must be established with firm data. 5. The geotechnical consultants must completely discuss how future movement of the active landslide could impact the proposed project and how the project (ie seepage pits) could Impact the downslope properties. 6, The geologic consultant has stated that the a landslide plane was not observed in the trenches. It should be noted the trenches were relatively shallow and that the active landslide west of the subject property Is a least 60 feet deep. Provide this office with deep subsurface data which defines the structure and stratigraphy beneath the subject site and west facing descending slope to Sepulveda Canyon. 7, The geologic consultant has stated that the subject site is within a meadow- like depression which is a former eroded elevated surface. This sounds a lot like the backward tilted surface within a landslide mass. Trench Log No. 7 indicates that the subject property is underlain by a very thick accumulation of Adobe/Qsw. This sounds like the thick accumulation of material on the backward tilted surface within a landslide mass. Please respond and discuss in detail. 8. Please explain in more detail the statement made In paragraph 4, sentence 4, page 2. The sentence starts with 'The drainage ravine along Sagebrush ties into 9. Please explain in more detail the statement made in paragraph 7, sentence 4, page 3. The sentence starts with "The debris could be described as sedimentary tuffaceous breccia " It must be noted that the Palos Verdes area has never been under to a desert like climate or a lake type environment. The "ancient slope failures" could simply be failures within the ancient slide mass or within the back scarp of G.B. Clevelends (1976) landslide. 10. Based upon previously submitted geologic data and geologic references it appears as if the entire west facing slope below Blackwater Canyon Road is, underlain by bedrock/landslide debris dipping to the west with minor fluctations. Please comment . 11. All recommendations of the consulting geologist and soils engineer must be incorporated into the design or shown as notes on the plans. 12. The plan must be specifically approved by the consultant geologist and soils engineer by manual, original signature(s) and date(s) on each sheet prior to approval by the Geology Section. Sent By: MATERIALS ENGINEERING; 626 458 4913; , Shet 2 of2 - • #13 Biackwater CanyonRoad Grading P.C. No. 0107180002 13. Add the following as notes to the plan: Jan-22-02 5:00PM; Page 2/4 • In -grading inspections must be made by the consulting geologist and soils engineer. Monthly in -grading inspection reports must be submitted directly to the Geology and Soils Section by the consultants. Prior to rough grading approval a final engineering geology and soils engineering report must be submitted to the Geology and Soils Section. An As -Built Geologic Map must be included in the final geology report. The final reports must Include statements in accordance with Sections 7021.3, 7021.2 and 111 of the Los Angeles County Building Code Foundation, wall, and pool excavations must be inspected and approved by the consulting geologist and soils,engineer prior to the placing of steel or concrete. 14. Show all proposed corrective measures (buttresses, stability fills, deep removals, etc.) on the plan. 15. The engineering geology report shall contain a finding regarding the safety of the building site for the proposed structure against hazard from future landsliding, settlement or slippage and a finding regarding the effect that the proposed building or grading construction will have on the geologic stability of property outside of the building site. The statement must be substantiated by appropriate data and analyses. 16. Provide data on the possible adverse Impact of the private sewage disposal system relative to site stability and adjacent properties. Discuss the path of migration of effluent and whether daylighting of the effluent will occur. Stability calculations must consider the effect on groundwater. Show on geologic cross section(s) the anticipated path and saturation from the effluent based on hydrogeology of the site. 17. The Soils Engineering review dated 8/25/01 is attached. 18. According to the submitted geotechnical report bedrock/soil samples where taken and tested in order to obtain shear strength values. The consulting engineering geologist and soils engineer must provide a detailed discussion regarding the applicability of the strength values obtained and the failure modes utilized in the slope stability analyses. 19. According to the geologic information presented adversely oriented bedding could impact the design of the proposed retaining wall. Please discuss and provide design recommendations as warranted. Support all discussions and recommendations with the appropriate data. 20. According to the submitted report the consultant engineering geologist has not reviewed the proposed grading plan. The consulting engineering geologist must review the plan and make specific findings, conclusions and recommendations. Note: Because of the fact that the submitted reports do not incorporate data on file at this office this does not represent a complete review of the proposed project. Pre A. Montgomery wed by , Date 8/7101 The 'Manual for Preparatl of Geotechnleal Reports' prepared b aunty of los Angeles. Department of Public Works is available on the Internet at the following address: http:/Idpw.co.la.ca. slmedfmartual.pdf p:4nepubnevhgeoiapy revlewVonmssFomL2 11/23199 Sent By: MATERIALS ENGINEERING; • 626 458 4913; Jan-22-02 5:00PM; • • Page 3/4 Address: Telephone: Fax: Calling hours • COUNTY OF LOS ANGELES DEPARTMENT OF PUBLIC WORKS LAND DEVELOPMENT DIVISION SOILS ENGINEERING REVIEW SHEET 900 S. Fremont Ave. Alhambra, CA 91803 (626) 458-4925 (626) 458-4913 - Monday through Thursday 8-9 a.m. & 3-4 p.m. Single Family Residence, Guest House, and Stable Tract Map 30345 Lot 2 Location 13 Blackwater Canyon Road. City of Rollin° Hills -5%+m.•'1 Developer/Owner Tony Fan • / C 1,1- . ). Engineer/Architect Politeo & Chona Soils Engineer T.I.N. (F.N. 000570) Geologist Art Keene Grading Plan Check No. 0107160002 Review of: Grading Plan Dated By Processing Center 07/31/01 Soils Engineering Report Dated 02/07/01 Geologic Report Dated 01/13/01 ACTION: Plan is not recommended for approval. REMARKS: District Office 12.02 Job No. B372001 Sheet 1 of 1 DISTRIBUTION: 1 Drainage 1 Grading 1 Geo/Soils Central File 1 District Engineer 1 Geologist 1 Soils Engineer 1 Engineer/Architect 1. Requirements of the Geology Section are attached. 2. Additional slope stability analysis may be required when the geology of the site is conclusively determined. 3. Address the recently activated landslide located at the adjacent property at 5 Sagebrush. Address any impact that the failure may have on the proposed development. 4. Provide appropriate data to conclusively determine the presence or absence of a regional deep seated landslide. Note that the subsurface exploration performed was relatively shallow and the active landslide on the adjacent property is approximately 60 feet in depth. 5. Provide static and seismic slope analyses for any deep seated landslide present. Also, provide a geotechnical cross section, for each section analyzed, showing the critical failure plane used in the analyses. Indicate the various shear strength parameters used in the analyses, in the appropriate segments of each failure plane. Show locations of the cross sections used in slope stability analyses on the geotechnical map. Recommend mitigation if factors of safety are below County minimum standards. 6. Provide references for all previous geotechnical reports reviewed for adjacent properties. Utilize the data in these reports in formulating the regional geologic characteristics for the subject site. No references list was contained in the report submitted. 7. Provide data on the possible adverse impact of the private sewage disposal system(s) relative to site stability and adjacent properties. Discuss the path of migration of the effluent and whether ponding or daylighting of the effluent will occur. Stability calculations must consider the effect of ponding/perched groundwater. Sent By: MATERIALS ENGINEERING; 626 458 4913; Jan-22-02 5:01PM; Page 4/4 • ' • COUNTY OF LOS ANGELES DEPARTMENT OF PUBLIC WORKS LAND DEVELOPMENT DIVISION SOILS ENGINEERING REVIEW SHEET Grading Plan Check No. Sheets 2 of 2 REMARKS (cont.): 8. The soils report shall contain a finding regarding the safety of the building site/grading construction against hazard from future landsliding, settlementorslippage and a finding regarding the effect that the proposed building or grading construction will have on the geologic stability of property outside of the building site. The finding must be substantiated by appropriate data and analysis. 9. Show the following on the grading plans: a. Approximate limits and depth of removal and recompaction of slide debris/unsuitable soils. b. Detail of keying and benching for placement of fill over slopes steeper than 5:1 gradient, c. Grading required for construction of any buttresses. d. All notes regarding fill compaction and density testing requirements. e. All recommend mitigation measures. 10. The Soils Engineer of record must review the grading plans and sign and stamp the plans in verification of his recommendations. Original manual signature and wet stamp are required, 11. Submit two sets of grading plans to the Soils Section for verification of compliance with County codes and policies. 12. Include a copy of this review sheet with your response. NOTE(S) TO THE PLAN CHECKER/BUILDING AND SAFETY DISTRICT ENGINEER: ON SITE SOILS ARE HIGHLY CORROSIVE TO FERROUS METALS AND HAVE A MEDIUM EXPANSION POTENTIAL. JJi Prepared by -e ;; •. �.' Date 08/25/01 / it •M. Alom `-.',rl t;;, t'.--' "x: c _Of: r,' : s NOTICE: Public safety, relative to g°technical subsurface exploration, shall `be prov'Ided in accordance with current codes for excavations, inclusive of the Los Angeles County Code, Chapter 11.48, and the State of California, Title 8, Construction Safety Orders. AMIR:13a