ARCHIVED REPORTS LEC APPLICATION FOR CERTIFICATION

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2.0 EXISTING GEOTECHNICAL REPORT REVIEW AND FIELD EXPLORATION 2.1 REVIEW OF EXISTING GEOTECHNICAL REPORTS A report titled Geotechnical Investigation Proposed Combustion Turbine Project No. I was performed by Kleinfelder Inc for the adjacent site in February, 1993. This report identified potential hazards specific for that site and the general area. Values contained in this section should not be used for design and are referenced here for informational purposes only. Kleinfelder, Inc. performed subsurface exploration using 8" augers using the mud-rotary technique. Samples were collected using a Modified California Sampler and Standard Penetration Sampler. Laboratory testing was performed on collected disturbed and relatively undisturbed samples. The logs of boring indicate the surface soils encountered generally consisted of loose silty and clayey sands and soft to medium stiff sandy silts and sandy silty clays extending to approximately 2 to 3 feet below ground surface. Two borings however had loose,silty sands extending to depths of approximately 8 feet below ground surface. Below these depths, alternating layers of medium stiff to hard sandy and silty clays,sandy and clayey silts,and medium dense to very dense silty,clayey,and relatively clean sands were encountered. Groundwater was encountered in all of the borings at depths of approximately 7 feet below ground surface. The report identifies isolated pockets of loose,near-surface,sandy soils beneath their site. Based on this information, it was their opinion that the liquefaction potential of some soils at the site is moderate to high. To mitigate the damage potential as a result of liquefaction, They recommended the site be over- excavated by 3 feet across the entire site, and 5 feet below heavily loaded structures and the material be recompacted as engineered fill. Based on these recommendations, Kleinfelder opinioned the risk of damage to structures from differential settlement would be reduced to tolerable levels. Kleinfelder anticipated that engineered fill compacted to 90 percent of the maximum dry density would have an allowable bearing capacity of 3,000 psf. Areas that were to support heavier structures was anticipated to have an allowable bearing capacity of 4,000 psf, provided the top 5 feet beneath these structures be over-excavated and recompacted to a minimum of 95 percent of the maximum dry density prior to the placement of 3 additional feet of engineered fill also compacted to a minimum of 95 %of the maximum dry density. Based on these site preparation recommendations, Kleinfelder anticipated total settlements on the order of 1/ inch and differential settlements of 1/ inch for spread foundations. 2.2 FIELD EXPLORATION Four Cone Penetrometer Test borings were sounded on June 2, 2008 within the project site as shown on the attached site plan (F2). The test boring locations are approximate based on estimated distances to prominent landmarks. The test borings were advanced to depths of approximately 50 feet under the supervision of Ms. Moranda Kellogg of Carlton. Borings were performed using a 20 ton capacity cone with a tip area of 15 square centimeters. Data was logged every 0.05 meters. Gregg Drilling provided correlations of subsurface conditions based on data collected during the CPT sounding. Additional subsurface testing was performed during the CPT sounding, including pore pressure dissipation tests and Shear wave velocities. The pore pressure dissipation tests were performed to evaluate the depth of groundwater, potential consolidation characteristics, and permeability at the Project No.5593-01-05 C A A LT O 7/29/2008 3 Eng ; n n n i , NCPA GFS.doc