Shear Strength Behavior of Soil-Sized Material Obtained from Landfill Mining, Waste-To-Energy Plants, and C&D Processing Plants

Abstract

The quantity of waste produced in Delhi is around 10,000 tons/day, and all the existing landfills are running out of their capacity. Due to the scarcity of available land, the focus is on reuse of waste. The bulk utilization/high-volume reuse of waste material is possible in geotechnical applications such as earthfills and embankments. For assessing the potential of a waste material, shear strength behavior has to be studied. In this experimental study, strength behavior of soil-sized material (less than 4.75 mm) obtained from (a) landfill mining of aged waste (mined MSW), (b) waste-to-energy plant (MSW incineration bottom ash), and (c) C&D processing plant (C&D waste) has been evaluated. The shear strength behavior of these soil-like materials from MSW is compared with that of locally available soil, i.e., Badarpur sand and Delhi silt. Direct shear tests (DST) on dry samples of all the materials and DST (saturated) on mined MSW, Delhi silt and triaxial tests on saturated samples of MSWI bottom ash, C&D waste, and Badarpur sand were conducted. From the results, it was observed that all three materials exhibit effective angle of shearing resistance (ϕ’) in the range of 36º–49º. The maximum value of shear strength was obtained for C&D waste (ϕ’ in the range of 45º–49º) followed by MSWI bottom ash (ϕ’ in the range of 42º–43º) and then by mined MSW (ϕ′ in the range of 36º–42º).