Engineering Properties of Municipal Solid Waste

Project Summary: This study was conducted to investigate engineering properties of municipal solid waste (MSW). Large-scale tests were conducted to determine hydraulic conductivity, shear strength, and compressibility of MSW as a function of placement conditions. Placement conditions were simulated by varying compaction (i.e., unit weight and moisture content) of test samples. Hydraulic conductivity decreased by more than two orders of magnitude as moisture content increased from the dry of optimum to the wet of optimum. The hydraulic conductivity was measured under constant head at a hydraulic gradient of 1 and decreased asymptotically from approximately 1.3x10-2 cm/s to 8x10-5 cm/s as the moisture content increased to optimum. The hydraulic conductivity of the MSW increased slightly wet of optimum. The internal angle of friction of the MSW was measured at 15% shear strain and decreased from approximately 40° to 30° with increasing moisture content. Test results demonstrated that both the compaction moisture content and dry unit weight had significant impact on the MSW geotechnical properties. However, compaction moisture content ultimately controlled the behavior. Overall trends were comparable for MSW and soil and included: increased dry density and increased stiffness to optimum moisture content; decreased hydraulic conductivity with increased compaction moisture content; and decreased shear strength with increased compaction moisture content. The results of the test program have environmental and economic implications for design and operation of landfills as well as post closure use.

Principal Investigator: Jim Hanson

Funding Agency: National Science Foundation (Partial Funding)

Publications:
Yesiller, N., Hanson, J. L., and Cox, J. T., (2013), “Determination of Specific Gravity of Municipal Solid Waste,” Waste Management, Elsevier, in review.

Hanson, J. L., Wong, W. W., and Yesiller, N., (2012), “Shear Strength of Municipal Solid Waste as a Function of Placement Conditions,” Proceedings, 2012 Global Waste Management Symposium, p. 1-4. 

Hanson, J. L., Yesiller, N., Von Stockhausen, S. A., and Wong, W. W., (2010), "Compaction Characteristics of Municipal Solid Waste," Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 136, No. 8, p. 1095-1102.  
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Yesiller, N., Wong, W. W., and Hanson, J. L., (2010), "Hydraulic Conductivity of Municipal Solid Waste as a Function of Placement Conditions," Proceedings Sixth International Conference on Environmental Geotechnics, New Delhi, India.