2021-04-27_PERMIT FILE - C1996083 (2)

Home Browse Search

�� Huddleston-Bers7 �i. Based upon the available data, the following parameters were utilized for the compacted gob. • ,1= 104.6 pcf • c' = 0 psf • �' = 34° Native Foundation Soils In general, the soil parameters utilized for the native foundation soils have been fairly consistent within the reviewed documentation. As a result, based upon the available data, the following parameters were utilized for the native foundation soils. • y = 125 pcf • c' = 100 psf • �' = 34- 3.3 Piezometric Surface In general, based upon our review of the available data, HBET does not believe that there is a free water surface, such as a static groundwater table, within the gob pile. However, the pore pressures recorded by the vibrating wire piezometers are not zero. As a result, the pore pressure data from the piezometers was used to generate a piezometric surface consistent with that data in order to evaluate the impacts of the pore pressures on the stability of the gob. HBET utilized data from VWP-05, VWP-06, and VWP-08 collected during June 2014 to generate the piezometric surface. It is important to note that VWP-09 is at a similar elevation to VWP-05; however, the pore pressures in VWP- 09 are lower than in VWP-05 making our use of the VWP-05 data conservative. Beyond the limits of the available piezometer data, HBET assumed a phreatic surface for the area of gob pile #2 below VWP-05. Beyond the toe, the phreatic surface was assumed to intersect and follow the ground surface. This is a conservative assumption. 3.4 Results Based upon DRMS Rule 4.10.4(2), a minimum Factor -of -Safety (FS) of 1.5 is required for the analyses to indicate a stable condition. below. The results of the analyses are included in Appendix A and are summarized • Gob Pile 42 Circular — minimum FS = 1.568 • Gob Pile #2 Block — minimum FS = 1.622 \2009 ALL PROJECTS OO439 - JE Slaser Associates Ir<00489-0003 Bono ohne'?00 - Geo Gob bFull Buildoui 007890003 8073061 Jo. 4