Shear Strength Characteristics of Municipal Solid Waste

Disposal of Municipal Solid Waste (MSW) has become a serious problem all over the world which is affected by the rising population and rapid urbanization. Most of the developed countries tend to proceed with engineered landfilling or incineration of solid waste while developing countries continue with open dumping. Most of these open dump sites are located on marshy lands or low lying land areas due to the high demand for prime lands in city areas, and they are expanded in vertical direction, saving the horizontal spaces. Therefore, physical, chemical and shear strength properties of MSW are timely important to overcome the stability failures of the dump sites during the operational period and after the closure of the dump sites. In this study, engineering properties of MSW were investigated using several laboratory experiments for disturbed waste samples collected from Meethotamulla dump site. In order to represent the aging effect of MSW, samples were extracted at different depths and variation of geotechnical properties with aging was analysed. Based on the laboratory test results, it can be noted that MSW in open dump sites in wet zone of Sri Lanka mainly consists of fine residue, aggregated soil, polythene and textiles. Further, higher shear strength parameters were obtained for MSW due to presence of textiles within the waste body. As such, it can be concluded that, it is necessary to consider the influence of textiles in analyzing the stability of open dump sites.