2019-01-18_REVISION - M1974086 (16)

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Ralston Quarry Slope Stability were constructed along the toe of the fill slope. These features are indicated in the historical Google Earth® image (above right). SUBSURFACE EXPLORATION Subsurface exploration for the project was conducted in August and October, 2018. Twelve (12) test holes were drilled with a conventional, track-mounted drilling rig advancing 4-inch diameter auger to evaluate the subsurface conditions and retrieve samples for laboratory testing. The test holes were advanced at the approximate locations shown on the Google Earth® image on the next page and in Figure 1 and Figure 2 following the text, to depths of approximately 19 to 35 feet below existing grade. (Test Hole 5, however, met refusal on coarse materials at a depth of about 5 feet. Test Hole 9 met refusal at a depth of about 16 feet; and Test Hole 11 at a depth of about 6 feet.) A GROUND engineer directed the subsurface exploration, logged the test holes in the field, and prepared the samples for transport to our laboratory. Samples of the subsurface materials were retrieved with a 2-inch I.D. California liner sampler. The samplers were driven into the substrata with blows from a 140-pound hammer falling 30 inches, a procedure similar to that described by ASTM Method D1586. Penetration resistance values, when properly evaluated, indicate the relative density or consistency of soils. Depths at which the samples were obtained and associated penetration resistance values are shown on the test hole logs. Logs of the test holes are presented in Figures 3, 4 and 5. The logs of Test Holes 1 through 4 are re-drawn to elevation in Figure 6. Construction details of the groundwater monitoring and observation points installed at Test Holes 1 through 4 are provided on Figures 7 through 10. Explanatory notes and a legend are provided in Figures 11 and 12. Job No 18-3046 GROUND Engineering Consultants, Inc. Page 3