Field monitoring and analysis of municipal solid waste landfill settlement

Settlement monitoring of a field-scale municipal solid waste landfill site in Shanghai Laogang Landfill was conducted since September 2006. The landfill site covered an area of 200 mx125 m and accepted about 150 000 tones of municipal solid waste from Shanghai. Maximum height of the wastes is about 9 m. Settlements at different depths of the landfill site during filling and after closure were monitored through horizontal inclinometers. The working principle of the horizontal inclinometer was introduced. Two years' monitoring data showed that bottom horizontal inclinometers settled from -3.6 cm to -5.7 cm. Wastes under the middle horizontal inclinometers experienced large compression due to the deposition of overlying wastes. The compression strain from the beginning of the overlying wastes' deposition to three months after the end of the deposition was about 0.197-0.242. Monitoring data from the top and middle horizontal inclinometers indicated that the time needed for the primary compression of wastes in the test site was about 3 months. Modified secondary compression index C' a was about 0.066-0.070, and was relatively large compared to published data which might due to the large amount of organic matter in the landfilled wastes.