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• <br /> Kennedy/Jenks Consultants <br /> The following are basic facts about coarse-grained soil classification: <br /> • The basic symbol G is used if the estimated percentage of gravel is greater than that for <br /> sand. In contrast, the symbol S is used when the estimated percentage of sand is greater <br /> than the percentage of gravel. <br /> • Gravels range in size from 3-inch to 0.25-inch (No. 4 sieve). Sands range in size from No. 4 <br /> sieve to No. 200 sieve. Use the grain size scale used by engineers (ASTM Standards <br /> D422-63 and D643-78) to further classify grain size as specified by the USCS. <br /> Note: This grain size scale differs from the Modified Wentworth Scale used in teaching most <br /> geologists. Also, it introduces a distinction between sorting and grading. <br /> • The modifying symbol W indicates good representation of all particle sizes. <br /> • The modifying symbol P indicates that there is a predominant excess or absence of particle <br /> sizes. <br /> • The symbol W or P is only used when there is less than 15 percent fines in a sample. <br /> • Modifying symbol M is used if fines have little or no plasticity (silty). <br /> • Modifying symbol C is used if fines have low to high plasticity (clayey). <br /> • The following rules apply for the written description of the soil group name: <br /> Types of Soil Rule <br /> Sands and gravels (clean) Less than 5 percent fines <br /> Sands (or gravels) with fines 5 to 15 percent fines <br /> Silty (or clayey) sands or gravels Greater than 15 percent fines <br /> • Other descriptive information includes: <br /> • Color <br /> • Maximum grain size <br /> • Composition of grains <br /> • Approximate percentage of gravel, sand, and fines (use a percentage estimation chart) <br /> Modifiers Description <br /> Trace Less than 5 percent <br /> Few 5 to 10 percent <br /> Little 15 to 25 percent <br /> Some 30 to 45 percent <br /> Mostly 50 to 100 percent <br /> • Mineralogy <br /> • Grain shape (round, subround, angular, subangular) <br /> • Moisture (dry, moist, wet) <br /> • Structure <br /> • Organic material <br /> • Odor <br /> Monitoring Well Installation Work Plan SOG 2 <br /> Delicato Family Vineyards, Manteca, California Page 3 <br /> g,*-WwpWdmmVob1071W65001.00_delk•Io109+fsMw s•N• pMlaMOx N26 hdek90 <br />