Laserfiche WebLink
4 f A-�NCONSTRUCTION <br /> qAA1PLI <br /> TESTING SERVICES <br /> Infiltration rates were calculated from the percolation data according to the Porchet Method. It should be <br /> noted that the percolation rate is related to, but not equal to,the infiltration rate. While an infiltration rate <br /> is a measure of the speed at which water progresses downward into the soil, the percolation rate measures <br /> not only the downward progression but the lateral progression through the soil as well.This reflects the fact <br /> that the surface area for infiltration testing would include only the horizontal surface while the percolation <br /> test includes both the bottom surface area and the sidewalls of the test hole. The Porchet Method is a <br /> relationship used to convert the values obtained by a percolation test to an approximate infiltration rate. <br /> The results of the interpreted percolation tests and computed infiltration rates are presented in the table <br /> below. <br /> Percolation i Infiltration Rates <br /> Testing Test Depth to Roorte Reporte Averaged • <br /> Location Hole Top of Percolation Percolation Percolation Infiltration Rate <br /> Total Bedding Rate on Data Rate from Rate (in/hr)4 <br /> Depth • reading <br /> PT-1 52.0 48.0 42.9 30 50.0 0.06 <br /> PT-2 51.5 46.5'MF 36.9 60 36.9 0.07 <br /> PT-3 50.5 47.0 52.5 60 40.0 0.03 <br /> PT-4 51.0 47.0 20.6 20 16.7 0.20 <br /> 'Reported percolation rate are the average of all the readings performed over the period of the test with valid data. <br /> 'Reported percolation rate from final reading is per the San Joaquin County Environmental Heald Department Policy <br /> for Percolation Test Procedure 98-01 <br /> 3Percolation rate is the avera ee of the final 3 readinjs. <br /> 4Infiltration rate computed from the change in head, time interval, borehole diameter, and average Head data <br /> collected during the percolation test. <br /> Subsurface soils are inherently variable both laterally and with depth. As such, an additional factor-of- <br /> safety should be included in the final design. <br /> If you have any questions regarding the contents of this letter, or if we could provide further assistance, <br /> please contact the undersigned. <br /> Sincerely, <br /> CONSTRUCTION TESTING SERVICES <br /> Bradford Quon, GE <br /> Principal Geotechnical Engineer <br /> Attachments: Plate 1 Vicinity Map <br /> Plate 2 Test Locations <br /> SJCEHD Approved Test Results <br /> 400 Yankee Hill Road,Rocklin,CA 95677•Phone(916)419-4747•Fax(916)419-4774 <br /> 2118 Rheem Drive,Pleasanton,CA 94588•Phone(925)462-5151 •Fax(925)462-5183 <br />