Modeling the flow behavior of a simulated municipal solid waste

Abstract

Flow slides in the municipal solid waste (MSW) landfill are common geological disasters that have the potential to cause loss of life, destruction of property, and damage to the natural environment in the surrounding region. In this work, a mixture of peat, kaolin clay and quartz sand was used as a model test material to simulate MSW. A series of physical model tests on MSW simulant flows was carried out to capture the run-out behavior of the waste and analyze its mobility. The testing assembly consisted of a transparent model box, a steel frame and a highspeed camera. Flow failure was induced by lifting up a baffle to cause the MSW simulant to collapse and flow. Images of the flowing mass were taken by the high-speed camera. The series of images clearly displays the propagation of MSW simulant flows. The final profile of the MSW simulant and the shape of the deposition area were observed and measured. The run-out distances, final deposit shapes, flow depth, velocities and angle of reach showed significant variation between test configurations, indicating the strong influence of moisture content on overall mobility. The test results obtained can aid in the prediction of distal reach, flow depth and maximum velocity of solid waste following a landfill slope failure, which are necessary for hazard assessment and mitigation planning, and also to provide physical data for theoretical and numerical model verification.

The catastrophic landfill flowslide at Hongao dumpsite on 20 December 2015 in Shenzhen, China

“…Landfill slope failure at MSW dumpsites can be found in previous studies, wherein six reported cases between 1993 and 2005 resulted in approximately 500 deaths and significant economic loss (Blight, 2008;Blight and Fourie, 2005;Eid et al, 2000;Kjeldsen and Fischer, 1995;Kocasoy and Curi, 1995;Merry et al, 2005;Mitchell et al, 1990). The deadliest event in history killed 278 people in Manila, Philippines, in 2000, and the second deadliest event killed 143 people and buried 71 houses on 21 February 2005 at the Leuwigajah dumpsite near Bandung, Indonesia (Lavigne et al, 2014).…”

“…The porosity and water content of MSW is typically high in an unregulated landfill because of inadequate drainage system, and therefore failures of MSWs commonly exhibit flowlike behaviors, i.e., flowslide, with extremely high mobility (e.g., Dai et al, 2016;Huang and Cheng, 2017). Landfill slope failure at MSW dumpsites can be found in previous studies, wherein six reported cases between 1993 and 2005 resulted in approximately 500 deaths and significant economic loss (Blight, 2008;Blight and Fourie, 2005;Eid et al, 2000;Kjeldsen and Fischer, 1995;Kocasoy and Curi, 1995;Merry et al, 2005;Mitchell et al, 1990).…”

“…Shear strength of MSW is a function of various parameters, including the type and composition of the waste, disposal rate, water content, surcharge, and compaction (Eid et al, 2000;Huvaj-Sarihan and Stark, 2008). The movement of waste failure is complex and still poorly known due to the lack of field monitoring data.…”

“…An energy balance approach was presented to estimate the maximum flow velocity of MSW slope failure (Blight and Fourie, 2005). The empirical-statistical method still has widespread use in practical applications, but the accuracy is model-dependent (Dai et al, 2016;Huang and Cheng, 2017). A mixture of peat, kaolinite, and quartz sand was used in laboratory tests to study the interplay between water content of filling and MSW failure, of which the results shown that, with increased water content of the MSW, the mobility increases while the maximum and final flow depth decrease (Dai et al, 2016).…”

“…The empirical-statistical method still has widespread use in practical applications, but the accuracy is model-dependent (Dai et al, 2016;Huang and Cheng, 2017). A mixture of peat, kaolinite, and quartz sand was used in laboratory tests to study the interplay between water content of filling and MSW failure, of which the results shown that, with increased water content of the MSW, the mobility increases while the maximum and final flow depth decrease (Dai et al, 2016). Numerical simulation has been widely used in landfill slope stability analysis (e.g., Chang, 2002Chang, , 2005Chugh et al, 2007;Huang and Cheng, 2017); some of the more advanced methods include the application of the smoothed-particle hydrodynamics (SPH) method (e.g., Huang et al, 2013) and the moving-particle semi-implicit (MPS) method (e.g., Huang and Zhu, 2014) for runout distance analysis of landfill flowslide.…”