垃圾填埋场边坡稳定可靠度分析

RELIABILITY ANALYSIS OF STABILITY OF A MUNICIPAL SOLID WASTE LANDFILL

高度非均质是垃圾土最突出的性质,其物理力学参数在时间和空间上均具有很大的变异性。基于现场取样进行室内测试,对垃圾土重度和抗剪强度参数的变异规律和概率特性进行研究,按分层概率特性和总体概率特性生成随机参数,采用蒙特卡罗法分析填埋边坡可靠度。研究结果表明,随埋深增加垃圾土有效黏聚力减小,有效内摩擦角增加,二者呈负相关特性,但在各个分层中,可认为二者彼此独立;按分层概率特性进行可靠度分析所得安全系数标准差较小,按总体概率特性进行分析标准差较大,前者分析结果更加准确可靠,说明对于高度非均质的垃圾土,为进行填埋边坡可靠度分析,首先必须研究和掌握其参数的变异规律和概率特性。

Waste is heterogeneous and its physico-mechanical parameters are characterized by extreme variability. Unit weight and shear strength of waste were measured by laboratory test on boring samples and the corresponding variation trend and probability characteristics were analyzed. Random parameters were generated according to the stratified and the overall probability characteristics. Reliability analyses were carried out using Monte Carlo method. The results show that as buried depth increases, effective cohesion of waste decreases whereas effective internal friction angle increases. There is a negative correlation between them. However, they are independent of each other in each waste layer. Standard deviation of safety factor obtained from reliability analyses considering stratified probability characteristics is smaller than that corresponding to overall probability characteristics. This illustrates that the variation trend and probability characteristics of waste parameters must be examined before a reliability analysis.