为了获得扩建垃圾堆体稳定分析所必需的抗剪强度参数,通过现场钻孔取样,利用改装的三轴压缩剪切仪,进行了不同填埋龄期垃圾原状样的室内三轴固结排水试验,着重研究填埋龄期对垃圾抗剪强度的影响规律。试验结果表明:垃圾土抗剪强度参数不仅与破坏应变取值相关,而且与填埋龄期之间有较好的规律性。随着填埋龄期的增加,垃圾中加筋成分(塑料及纤维等)减少,而渣土成分显著增加,导致其凝聚力随龄期增加而减小,而摩擦角随龄期增加而变大。可见,进行垃圾堆体稳定分析时,不仅要选择合适的破坏应变水平,也要根据填埋龄期分层取抗剪强度参数值。
To provide shear strength parameters for slope stability analyses of expanded landfills, borehole samples of MSW with different fill ages obtained from a landfill were used in consolidated drained triaxial shear tests. Two conventional triaxial apparatus were modified to account for the high compressibility of MSW specimens. On the basis of the test results, the relationship between the shear strength of the MSW and the fill age was developed. The test results demonstrated that the shear strength parameters (c' and φ' ) were related to not only the strain level but also the fill age. As the fill age increases, the cinder content of the MSW increases while the amount of reinforcing components such as plastics and fiber decreases, resulting in decrease of the cohesion and increase of the friction angle of the MSW. The test results indicated that different values of c and φ should be chosen for the sub-layers of MSW with different fill ages for slope stability analysis of the landfill body.