ARCHIVED REPORTS_1989 - Laserfiche WebLink

Home Browse Search

w The engineering properties of the refuse fill and foundation soils were evaluated either indirectly by empirical methods, or from EMCON's experience with similar materials on other projects. The strength parameters used in the stability analy- ses for each material are presented in Table 1. The following section summa- rizes the engineering properties of the materials evaluated. 3.1 LANDFILL REFUSE Shear strength properties of refuse -soil mixtures are not easily determined be- cause refuse materials are difficult to sample and generally unsuitable for con- ventional laboratory strength testing. Figure 2 shows a relationship of cohesion and friction strength parameters developed from the results of a full-scale load test on a typical refuse landfill (Converse, 1975). The average strength parameter of the refuse -soil mixture used in the slope sta- bility analysis of the landfill were a cohesion of 400 pounds per square foot (psf), and an internal friction angle of 20 degrees. When compacted in place, a com- bined refuse -soil mixture average unit weight of about 60 pounds per cubic foot (pcf) was assumed for analysis. Engineering properties of the foundation soils are primarily based on evaluation of the boring logs, which were performed by EMCON and JHKA. 3.2.1 Clayey and Silty Sand Stratum The clayey and silty sand stratum was assumed to be a medium dense clayey and silty sand extending from the ground surface (approximately 120 feet MSL) to 100 feet deep (approximately 20 feet MSL). This stratum was interbedded with layers of sandy clay and sandy silt. For static and seismic stability, the sand stratum was assumed to be weakly cemented and to have a 350 psf cohesion with a friction angle of 35 degrees and a total unit weight of 125 pcf. PJ9 9390217.00W 6 Rev. 0 May 23, 1989