FINAL REPORT OF TESTING AND OBSERVATION SERVICES PERFORMED DURING SITE GRADING

Transcription

1 FINAL REPORT OF TESTING AND OBSERVATION SERVICES PERFORMED DURING SITE GRADING QUARRY FALLS (CIVITA UNITS B AND C, LOTS 1, 2, 3, 4, AND 5) I. O. NO P. T. S. NO DRAWING NO D SAN DIEGO, CALIFORNIA PREPARED FOR QUARRY FALLS, LLC SAN DIEGO, CALIFORNIA JULY 29, 2014 PROJECT NO B

2 GROCON INCORPORATED GEOTECHNICAL ENVIRONMENTAL MATERIALSO Project No B July 29, 2014 Quarry Falls, LLC 5465 Morehouse Drive, Suite 260 San Diego, California Attention: Subject: Mr. Mark Radelow FINAL REPORT OF TESTING AND OBSERVATION SERVICES PERFORMED DURING SITE GRADING QUARRY FALLS (CIVITA UNITS B AND C, LOTS 1, 2, 3, 4, AND 5) I. O. NO ; P. T. S. NO ; DRAWING NO D SAN DIEGO, CALIFORNIA Dear Mr. Radelow: In accordance with your request, we have provided compaction testing and observation services during grading of Quarry Falls (Civita) Units B and C. Our services were performed during the period of August 23, 2012, and August 12, The scope of our services included the following: Observing the grading operation, including the processing of the surface of existing previously placed fill soil. Performing in-place density tests in fill placed and compacted at the site. Performing laboratory tests to aid in evaluating the compaction and expansion characteristics of various soil types encountered and/or used for fill. Additionally, laboratory tests were performed on samples of soil present near finish grade in Lots 1, 2, 3, and 5 to evaluate expansion characteristics and water-soluble sulfate content. Preparing an As Graded Geologic Map. Preparing this final report of grading. GENERAL Quarry Falls Units B & C are located along the southern portion of the overall Quarry Falls (Civita) property that comprises approximately 215 acres of land situated north of Friars Road between Mission Center Road and I-805 (see Vicinity Map, Figure 1). The grading contractor was F. J. Willert Contracting Company, Inc. Rick Engineering prepared the project grading plans titled Grading Plans 6960 Flanders Drive San Diego, California Telephone Fax

3 for Quarry Falls (Civita) Units B and C, San Diego, California, I.O. No , P.T.S. Number , Drawing No D. The project geotechnical report, prepared by Geocon Incorporated, is titled Geotechnical Investigation, Unit B and C, Quarry Falls (Civita), San Diego, California, dated April 24, 2012 (Project No ). References to elevations and locations herein were based on surveyors or grade checkers stakes in the field and interpolation from the referenced plans. Geocon Incorporated did not provide surveying services and, therefore, has no opinion regarding the accuracy of the elevations or surface geometry with respect to the approved plans. PREVIOUS GRADING Vulcan Materials used the property previously to mine and produce sand and aggregate products. Mining occurred over several decades resulting in the removal of rock and soil deposits from deep excavations. The deep excavations were backfilled with waste soils generated during mining activities, which resulted in relatively thick undocumented fill deposits with abrupt, near-vertical, sidewall contact with the adjacent geologic formation. In 2003, reclamation grading commenced with the removal of undocumented fill. Placement of compacted fill started in April 2004 and continued through Geomatrix Consultants, Inc., and AMEC Geomatrix, Inc., performed compaction testing and observation during reclamation grading. Geomatrix and AMEC Geomatrix reported that the fill was compacted to at least 90 percent of the laboratory maximum dry density. A summary of compaction test results is provided in Geomatrix s and AMEC Geomatrix s annual reclamation grading reports (see References). Overall reclamation grading resulted in compacted fills up to approximately 130 feet thick. Cut and fill slopes with inclinations of 1.5:1 and 2:1 (horizontal to vertical), respectively, with maximum heights up to 70 feet were constructed along perimeter of sheet-graded pads. Reclamation grading on lots within Units B and C resulted in compacted fills up to approximately 30 to 40 feet thick. Fill slopes with inclination of 2:1 (horizontal:vertical) or flatter, and maximum heights of 25 feet were also constructed south of the pad for the detention basin during grading for the adjacent Civita Phase A project. GRADING Recent grading on Units B and C resulted in the placement of approximately 2 to 12 feet of additional compacted fill above reclamation grades. Prior to placing new fill, the upper approximately 1-foot of previously placed fill was scarified, moisture conditioned as necessary, and compacted. Fill soil, derived from excavations within Units B & C or the adjacent Unit F, were then placed and compacted Project No B July 29, 2014

4 in layers until the design elevations were achieved. The fill soils generally consisted of silty clay and clayey sand. Lot No. 4 was partially graded and left at a rough elevation varying from 57 feet above Mean Sea Level (MSL) at the southwest corner to rough elevation of 62 feet MSL at the northeast section per field verifications by a Geocon representative in a field memo dated January 8, Subsequent to this field memo, the lot was used as a disposal site for excess soil from adjacent Civita projects. The disposal soils were placed without observation and compaction testing and were considered nonstructural fill. Subsequently, the nonstructural fill and previously documented fill was removed to an elevation of approximately 3 to 5 feet below the previous documented structural fill elevation. It is estimated that the structural fill elevation is at approximately 55 feet MSL. Recently, additional nonstructural fill has been placed across Lot 4. The as-graded geotechnical map (Figure 2) shows this area as undocumented fill that will require complete removal during future grading operations. Grades on Lot 5 were left approximately 1 to 3 feet below finish sheet grades shown on the grading plan. Any additional fill placed on the lot should be placed and compacted as recommended in the project geotechnical report under the observation and compaction testing of Geocon Incorporated. During grading operations, Geocon Incorporated observed compaction procedures and performed in-place density tests to evaluate the dry density and moisture content of the fill soil. We performed in-place density tests in general conformance with the current versions of ASTM D 6938, Standard Test Method for Density of Soil and Soil-Aggregate in Place by Nuclear Methods. The results of the in-place dry density and moisture content tests are summarized in Table I. Where fill soil contained rock larger than ¾-inch, a correction was made to the laboratory maximum dry density and optimum moisture content using methods suggested by AASHTO T The values of maximum dry density and optimum moisture content presented on Table I reflect these corrections. In general, the results of the in-place dry density tests indicate that the fill soil has a dry density of least 90 percent of the maximum dry density near or slightly above optimum moisture content at the locations tested. The approximate locations of the in-place dry density tests are shown on the As-Graded Geologic Map, Figure 2 (map pocket). We performed laboratory tests on samples of soil used for fill to evaluate moisture-density relationships, optimum moisture content and maximum dry density (ASTM D 1557), expansion potential (ASTM D 4829), and water-soluble sulfate content (California Test No. 417). The results of the laboratory tests are summarized on Tables II through IV. Project No B July 29, 2014

5 Slopes In general, fill slopes have planned inclinations of 2:1 (horizontal:vertical) or flatter, with maximum heights of approximately 30. The slopes were constructed by cutting into the previously placed fill soil or placing new fill. All slopes should be planted, drained, and maintained to reduce erosion. Slope irrigation should be kept to a minimum to just support the vegetative cover. Surface drainage should not be allowed to flow over the top of the slope. Finish Grade Soil Conditions Observations and laboratory test results indicate that the prevailing soils within the upper approximately 3 feet of finish grade are considered to be expansive (expansion index [EI] of greater than 20) as defined by 2013 California Building Code (CBC) Section Table 1 presents soil classifications based on the EI in accordance with ASTM D A summary of the laboratory results are presented on Table III. TABLE 1 SOIL CLASSIFICATION BASED ON EXPANSION INDEX ASTM D 4829 Expansion Index (EI) Soil Classification 0 20 Very Low Low Medium High Greater Than 130 Very High We performed laboratory tests on samples of the site soils to evaluate the percentage of water-soluble sulfate content. The test results are presented in Table IV and indicate that the on-site soils at the locations tested possess Not Applicable or S O sulfate exposure to concrete structures as defined by 2013 CBC Section 1904 and ACI Sections 4.2 and 4.3. The presence of water-soluble sulfates is not a visually discernible characteristic; therefore, other soil samples from the site could yield different concentrations. Additionally, over time landscaping activities (i.e., addition of fertilizers and other soil nutrients) may affect the concentration. Geocon Incorporated does not practice corrosion engineering. Therefore, if improvements that could be susceptible to corrosion are planned, further evaluation by a corrosion engineer may be needed. Project No B July 29, 2014

6 SOIL AND GEOLOGIC CONDITIONS The soil and geologic conditions encountered during grading were found to be similar to those described in the project geotechnical report. The grading was performed in accordance with recommendations provided in the project soil reports. The site is underlain by compacted fill with a maximum thickness up to approximately 40 feet. The compacted fill is comprised of previously placed fill for reclamation grading and compacted fill placed during recent Quarry Falls (Civita) Units B & C grading. The fill overlies the Stadium Conglomerate. The As-Graded Geologic Map depicts the general geologic conditions observed. CONCLUSIONS AND RECOMMENDATIONS 1.0 General 1.1 Based on observations and test results, it is the opinion of Geocon Incorporated that the grading that has occurred to date has been performed in substantial conformance with the recommendations of the referenced project soil report. Soil and geologic conditions encountered during grading that differ from those expected by the project soil report are not uncommon. Where such conditions required a significant modification to the recommendations of the project soil report, they have been described herein. 1.2 Geocon Incorporated certifies that the soil engineering and engineering geologic aspects of the grading are in compliance with the approved geotechnical report and the grading plans, Drawing No D. The term certify or certification used in this report is defined by Section of the State of California Professional Engineers Act, effective January 1, 2005, which states: The use of the word "certify" or "certification" by a registered professional engineer in the practice of professional engineering or land surveying constitutes an expression of professional opinion regarding those facts or findings which are the subject of certification, and does not constitute a warranty or guarantee, either expressed or implied. 1.3 No soil or geologic conditions were observed during grading that would preclude the continued development of the property as planned. Based on laboratory test results and field observations, it is the opinion of Geocon Incorporated that the compacted fill observed and tested as part of the grading for this project was generally compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content. Project No B July 29, 2014

7 2.0 Future Grading 2.1 Any additional grading performed at the site should be accomplished in conjunction with our observation and compaction testing services. Geocon should review future grading plans prior to finalizing. Trench and wall backfill should be compacted to a dry density of at least 90 percent of the laboratory maximum dry density near or above optimum moisture content. This office should be notified at least 48 hours prior to commencing additional grading or backfill operations. 3.0 Site Drainage and Moisture Protection 3.1 Adequate site drainage is critical to reduce the potential for differential soil movement, erosion and subsurface seepage. Under no circumstances should water be allowed to pond adjacent to footings. The site should be graded and maintained such that surface drainage is directed away from structures in accordance with 2013 CBC or other applicable standards. In addition, surface drainage should be directed away from the top of slopes into swales or other controlled drainage devices. Roof and pavement drainage should be directed into conduits that carry runoff away from the proposed structure. 3.2 In the case of basement walls or building walls retaining landscaping areas, a waterproofing system should be used on the wall and joints, and a Miradrain drainage panel (or similar) should be placed over the waterproofing. The project architect or civil engineer should provide detailed specifications on the plans for all waterproofing and drainage. 3.3 Underground utilities should be leak free. Utility and irrigation lines should be checked periodically for leaks, and detected leaks should be repaired promptly. Detrimental soil movement could occur if water is allowed to infiltrate the soil for prolonged periods of time. LIMITATIONS The conclusions and recommendations contained herein apply only to our work with respect to grading, and represent conditions on the date of our final observation on August 12, Any subsequent grading should be done in conjunction with our observation and testing services. As used herein, the term observation implies only that we observed the progress of the work with which we agreed to be involved. Our services did not include the evaluation or identification of the potential presence of hazardous or corrosive materials. Our conclusions and opinions as to whether the work essentially complies with the job specifications are based on our observations, experience and test results. Subsurface conditions, and the accuracy of tests used to measure such conditions, can vary greatly at any time. We make no warranty, express or implied, except that our services were performed in accordance with engineering principles generally accepted at this time and location. Project No B July 29, 2014

8 We will accept no responsibility for any subsequent changes made to the site by others, by the uncontrolled action of water, or by the failure of others to properly repair damages caused by the uncontrolled action of water. The findings and recommendations of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and should not be relied upon after a period of three years. If you have any questions regarding this report, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED Rodney C. Mikesell GE 2533 Garry W. Cannon RCE CEG 2201 RCM:GWC:dmc (2) Addressee (1) Devcon CPM Attention: Mr. Matt Adams (3/del) Rick Engineering Company Attention: Mr. Troy Bales Project No B July 29, 2014

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11 Test No. Date Location TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Elev. or Depth (ft) 1 08/23/12 Russell Parkway W /23/12 Russell Parkway /23/12 Russell Parkway /23/12 Russell Parkway /23/12 Russell Parkway /23/12 Russell Parkway /23/12 Russell Parkway /23/12 Russell Parkway /23/12 Russell Parkway /23/12 Russell Parkway /23/12 Russell Parkway /24/12 Russell Parkway /24/12 Russell Parkway /24/12 Russell Parkway /24/12 Russell Parkway /24/12 Russell Parkway /27/12 Lot /27/12 Lot /27/12 Lot /27/12 Lot B /27/12 Lot /27/12 Lot /28/12 Lot /28/12 Lot /28/12 Lot /28/12 Lot /28/12 Lot /28/12 Lot /29/12 Lot /29/12 Lot /30/12 Lot Curve No. Plus 3/4" Rock MDD OMC Dry Dens. Moist. Cont. Req'd. Project No B July 29, 2014

12 Test No. Date Location TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Elev. or Depth (ft) 32 08/30/12 Lot /30/12 Lot /30/12 Lot /30/12 Lot /30/12 Lot /30/12 Lot /30/12 Lot /31/12 Lot /31/12 Lot /31/12 Lot /31/12 Lot /31/12 Lot /31/12 Lot /31/12 Lot /31/12 Lot /04/12 Lot /04/12 Lot /04/12 Lot A 09/04/12 Lot /04/12 Lot /04/12 Lot /04/12 Lot /04/12 Lot /04/12 Lot /05/12 Lot /05/12 Lot /05/12 Lot /05/12 Lot /05/12 Lot FG 60 11/01/12 Lot FG 61 11/01/12 Lot Curve No. Plus 3/4" Rock MDD OMC Dry Dens. Moist. Cont. Req'd. Project No B July 29, 2014

13 Test No. Date Location TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS FG 62 11/01/12 Lot FG 63 11/01/12 Lot FG 64 11/01/12 Lot FG 65 11/01/12 Lot /01/12 Lot Elev. or Depth (ft) 67 11/01/12 Civita Boulevard /01/12 Civita Boulevard /07/12 Civita Boulevard /07/12 Civita /07/12 Lot /07/12 Lot /07/12 Lot /07/12 Lot /07/12 Lot /07/12 Civita Boulevard /07/12 Civita Boulevard /09/12 Lot /09/12 Lot /09/12 Lot /09/12 Lot /09/12 Lot /09/12 Lot /09/12 Lot /09/12 Lot A 11/09/12 Lot /09/12 Lot /09/12 Lot B /09/12 Lot B /09/12 Lot B /13/12 Lot B /13/12 Lot B Curve No. Plus 3/4" Rock MDD OMC Dry Dens. Moist. Cont. Req'd. Project No B July 29, 2014

14 Test No. Date Location TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Elev. or Depth (ft) 92 11/13/12 Lot B W of Bio-swale /13/12 Lot B E of Bio-swale /13/12 Lot B W of Bio-swale /14/12 Lot B E of Bio-swale /14/12 Lot B S End /14/12 Lot B /14/12 Lot B /14/12 Lot B /14/12 Lot B /16/12 Lot B /16/12 Lot B /20/12 Lot 4 W Edge /20/12 Lot 5 W Edge /20/12 Lot 4 W Edge /20/12 Lot 5 W Edge /26/12 Lot 4 S End /26/12 Lot 4 S End A 11/26/12 Lot 4 S End /26/12 Lot 4 S End /26/12 Lot 4 S End /27/12 Lot 4 S End /27/12 Lot 4 S End /27/12 Lot 4 S End /28/12 Lot 4 S End /28/12 Lot 4 S End /28/12 Lot 4 E End /28/12 Lot 4 E End ST /11/12 S Lot ST /11/12 S Lot ST /11/12 S Lot /19/13 SE Corner of Lot 1 Basin Refill Curve No. Plus 3/4" Rock MDD OMC Dry Dens. Moist. Cont. Req'd. Project No B July 29, 2014

15 Test No. Date Location TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Elev. or Depth (ft) /19/13 SE Corner of Lot 1 Basin Refill /19/13 SE Corner of Lot 1 Basin Refill A 03/19/13 SE Corner of Lot 1 Basin Refill /19/13 SE Corner of Lot 1 Basin Refill /19/13 SE Corner of Lot 1 Basin Refill /26/13 Road Between Lots 4 & /26/13 Road Between Lots 4 & /26/13 Road Between Lots 4 & /26/13 Road Between Lots 4 & /26/13 Road Between Lots 4 & A 06/26/13 Road Between Lots 4 & /26/13 Road Between Lots 4 & A 06/26/13 Road Between Lots 4 & /26/13 Road Between Lots 4 & /26/13 Road Between Lots 4 & /26/13 Road Between Lots 4 & /27/13 Basin Lot /27/13 Basin Lot /27/13 Between Lots 4 & /27/13 Between Lots 4 & /27/13 Between Lots 4 & /08/13 Lot /08/13 Lot /08/13 Lot /08/13 Lot /08/13 Lot /08/13 Lot /09/13 Lot /09/13 Lot /09/13 Lot /09/13 Lot Curve No. Plus 3/4" Rock MDD OMC Dry Dens. Moist. Cont. Req'd. Project No B July 29, 2014

16 Test No. Date Location TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Elev. or Depth (ft) /09/13 Lot A 08/12/13 Lot /12/13 Lot /12/13 Lot A 08/12/13 Lot /12/13 Lot /12/13 Lot /12/13 Lot /12/13 Lot Curve No. Plus 3/4" Rock MDD OMC Dry Dens. Moist. Cont. Req'd. Project No B July 29, 2014

17 - TEST SUFFIX TABLE I EXPLANATION OF CODED TERMS A, B, C,... : Retest of previous density test failure, following moisture conditioning and/or recompaction. - STRIKE-OUT Fill in this area was removed. - PREFIX CODE DESIGNATION FOR TEST NUMBERS FG - CURVE NO. Corresponds to curve numbers listed in the summary of laboratory maximum dry density and optimum moisture content test results table for selected fill soil samples encountered during testing and observation. - ROCK CORRECTION For density tests with rock percentage greater than zero, laboratory maximum dry density and optimum moisture content were adjusted for rock content. For tests with rock content equal to zero, laboratory maximum dry density and optimum moisture content values are unadjusted. - TYPE OF TEST - FINISH GRADE ST - SLOPE TEST SC: Sand Cone Test (ASTM D 1556) NU: Nuclear Density Test (ASTM D 6938 and D 2950) OT: Other - ELEVATION/DEPTH Test elevations/depths have been rounded to the nearest whole foot. Project No B July 29, 2014

18 Sample No. TABLE II LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST RESULTS ASTM D 1557 Description Maximum Dry Density Optimum Moisture Content (% dry weight) 8 Light yellowish brown Clayey SAND with little silt Lot No. TABLE III SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS ASTM D 4829 Sample No. Moisture Content Before Test After Test Dry Density Expansion Index ASTM Classification 1 EI Low 2 EI Low 3 EI Low 5 EI Very Low TABLE IV SUMMARY OF WATER SOLUBLE SULFATE LABORATORY TEST RESULTS CALIFORNIA TEST NO. 417 Lot No. Sample No. Water Soluble Sulfate Sulfate Exposure 1 EI Not Applicable 2 EI Not Applicable 3 EI Not Applicable 5 EI Not Applicable Project No B July 29, 2014

19 LIST OF REFERENCES 1. Geomatrix, Progress Report 1, Vulcan Materials Company Mission Valley Facility Rework Project, San Diego, California, dated April 12, Geomatrix, Progress Report 2, Vulcan Materials Company Mission Valley Facility Rework Project, San Diego, California, dated July 5, Geomatrix, Progress Report 3, Vulcan Materials Company Mission Valley Facility Rework Project, San Diego, California, dated March 30, Geomatrix, Progress Report 4, Vulcan Materials Company Mission Valley Facility Rework Project, San Diego, California, dated March 28, Geomatrix, Progress Report 5, Vulcan Materials Company Mission Valley Facility Rework Project, San Diego, California, dated June 1, AMEC Geomatrix, Inc., Progress Report No. 6, Vulcan Materials Company, Mission Valley Facility Rework Project, San Diego, California, dated April 22, AMEC Geomatrix, Inc., Progress Report No. 7, Vulcan Materials Company, Mission Valley Facility Rework Project, San Diego, California, dated June 15, AMEC Geomatrix, Inc., Progress Report No. 8, Vulcan Materials Company, Mission Valley Facility Rework Project, San Diego, California, dated May 10, Historic and Future Pit Floor, Mission Valley Plant, prepared by Vulcan Materials Company, dated February 7, Project No B July 29, 2014