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File: 218267 November 30, 2018 Subsurface Exploration On November 8, 2018 we drilled four borings at the site at the locations shown on Figure 4. The borings were drilled using a Mobile B-24 truck-mounted drilling rig equipped with 4.0 inch diameter, helical flight augers. Logs of the soils encountered during drilling record our observations of the cuttings traveling up the augers and of relatively undisturbed samples collected from the base of the advancing holes. The final boring logs are based upon the field logs with occasional modifications made upon further laboratory examinations of the recovered samples and laboratory test results. The final logs are attached in Appendix A. The relatively undisturbed samples were obtained by driving a 3.0 inch (outer diameter) Modified California Sampler into the base of the advancing hole by repeated blows from a 140 pound hammer lifted 30 inches. On the logs, the number of blows required to drive the sampler the final 12 inches of the 18 inch drive, have been recorded as the Blow Counts. These blows have not been adjusted to reflect equivalent blows of any other type of sampler or hammer, Subsurface Conditions Borings 1, 2, and 4 penetrated stiff to very stiff silty clay down to their terminated boring depths of 12.5, 18.5, and 19.5 feet. Boring 3 first penetrated 10.5 feet of very stiff silty clay. The clay was underlain by silty sand with gravel down to the terminated boring depth of 11.5 feet. Please refer to Appendix A for a more detailed description of each boring. No free groundwater was encountered during the drilling of the holes. However, during periods of heavy rain or late in the winter, groundwater seepage may exist at shallower depths, most likely as perched water atop the stiffer clays, or within a deeper sandy layer (e.g. BH-3). Laboratory Testing The relatively undisturbed samples collected during the drilling process were returned to the laboratory for testing of engineering properties. In the lab, selected soil samples were tested for moisture content, density, and plasticity. The results of the laboratory tests are attached to this report in Appendix B. Plasticity Index (PI)testing performed on the clayey materials produced Pi results of 21, 24, 34, and 41. This testing indicated that the near surface materials have high plasticity and are highly expansive, while the deeper samples (below about 6 feet) were of moderate plasticity and were judged to be moderately expansive. 4