Department of Civil and Environmental Engineering, University of Michigan, 2358 GG Brown Laboratory, 2350 Hayward Street, Ann Arbor, MI 48109, USA.
Waste Manag. 2010 Aug-Sep;30(8-9):1544-55. doi: 10.1016/j.wasman.2010.01.024. Epub 2010 Feb 11.
Large direct shear testing (300 mm x 300 mm box) of municipal solid waste (MSW) collected from a landfill located in the San Francisco Bay area was performed to gain insight on the shear response of MSW. The study investigated the effects of waste composition, confining stress, unit weight, and loading rate on the stress-displacement response and shear strength of MSW. The amount and orientation of the fibrous waste materials in the MSW were found to play a critical role. The fibrous material had little effect on the MSW's strength when it was oriented parallel to the shear surface, as is typically the case when waste material is compressed vertically and then tested in a direct shear apparatus. Tests in which the fibrous material was oriented perpendicular to the horizontal shear surface produced significantly stronger MSW specimens. The test results indicate that confining stress and loading rate are also important factors. Based on 109 large-scale direct shear tests, the shear strength of MSW at low moisture contents is best characterized by cohesion=15 kPa, friction angle=36 degrees at a normal stress of 1 atmosphere, and a decrease in the friction angle of 5 degrees for every log-cycle increase in normal stress.
对取自旧金山湾区垃圾填埋场的城市固体废物（MSW）进行了大型直接剪切试验（300mmx300mm 盒），以深入了解 MSW 的剪切响应。该研究调查了废物组成、围压、容重和加载速率对 MSW 应力-位移响应和剪切强度的影响。MSW 中纤维状废物材料的数量和方向被发现起着关键作用。当纤维材料平行于剪切面取向时，对 MSW 的强度几乎没有影响，因为当废物材料垂直压缩然后在直接剪切仪中进行测试时，通常就是这种情况。当纤维材料垂直于水平剪切面取向时，产生的 MSW 试样强度明显更高。试验结果表明，围压和加载速率也是重要因素。基于 109 个大型直接剪切试验，低含水量下 MSW 的剪切强度特征最佳，可表示为凝聚力=15kPa，摩擦角=36 度，在 1 个大气压的正常应力下，摩擦角随正常应力每对数循环增加 5 度而减小。
