基于土石坝潜在滑裂面上等效地震系数的概念,在城市垃圾填埋场防渗层的二维滑动面上定义了水平等效加速度(时程)ahec(t)和ahed(t),以最大水平等效加速度ahecm和ahedm代表地震在填埋场覆盖层和衬垫层引起的荷载水平,与屈服加速度进行比较来评价填埋场的地震稳定性;假定沿填埋场底部衬垫层的潜在滑动体由3个刚性滑块组成,对基础具有一定坡角的填埋场进行极限平衡分析,推导了填埋场衬垫层屈服加速度系数的计算公式;将等效线性化方法与拟静力方法相结合,给出城市垃圾填埋场沿防渗层失稳的2D拟静力分析步骤;对振动台试验用到的模型填埋场进行非线性数值计算,结合试验结果验证了提出的2D拟静力分析方法能够给出相对保守的地震稳定性评价结果。
Based on the concept of the equivalent seismic coefficient on the potential sliding surface of soil-rock dams,the horizontal landfills equivalent accelerations(time-history) ahec(t) and ahed(t) are defined for the top covers and base linings.The maximum horizontal equivalent accelerations ahecmand ahedm,which are regarded as the loading levels induced by earthquakes,are compared with the yield accelerations of covers and linings respectively to evaluate the seismic stability of landfills.Supposing that the potential sliding mass above the landfill base linings is composed of three rigid blocks,a formula to estimate the yield acceleration of base linings of landfills approximately is derived based on the limit equilibrium analysis.By combining the equivalent linearization method with the pseudo-static analysis,the process of pseudo-static analysis to evaluate the earthquake stability of 2D landfills is given.Nonlinear numerical calculation of the landfill models used in table tests indicates that the conservative results can be given by the proposed pseudo-static analysis method.