垃圾坝和界面强度对填埋场沿底部衬垫系统滑动的影响

为研究垃圾坝和界面强度对填埋场沿底部衬垫系统滑动的影响,将填埋场分为主动楔体、被动楔体和垃圾坝3个部分,对其进行极限平衡分析,建立平衡方程,求解填埋场的安全系数。考虑条间力的变化,可以计算填埋场的最大安全系数FSmax和最小安全系数FSmin,并且采用平均安全系数FSave来代替真实安全系数FStrue。填埋场的安全系数随着垃圾坝高度和底部摩擦角的增加逐渐增大,如果不考虑垃圾坝的作用,填埋场的稳定计算偏于保守。具有最小安全系数的潜在滑动面并不能仅仅通过比较衬垫中不同界面的黏聚力和内摩擦角来确定,随着衬垫界面摩擦角和黏结力的增加,FSave都在逐渐增大,衬垫界面黏结力对填埋场的整体稳定性影响较大,尤其是对于摩擦角较小、黏结力较大的情况。

EFFECTS OF RETAINING WALL AND INTERFACE STRENGTH ON TRANSNATIONAL FAILURE OF LANDFILL ALONG UNDERLYING LINER SYSTEM

To investigate the effects of retaining wall and interface strength on translational failure of landfill along the underlying liner system,a three-part wedge analysis is used to calculate the safety factor for the waste mass against possible translational failure.The landfill can be divided into three discrete parts:an active wedge lying on the back slope that tends to cause failure;a passive wedge;and retaining wall resting on the foundation or liner system that helps to resist failure.With the change of the interwedge forces,the upper and lower bound solutions for the landfill stability,i.e.FSmax and FSmin,can be readily determined.Using an average safety factor FSave to replace the true factor FStrue,the differences between FSave and FStrue are within 5% for all cases considered.The safety factors increase with the increase of the height of retaining wall and the friction angle beneath the retaining wall.It is found that the retaining wall affects significantly the stability of landfill,if not consider the retaining wall,the stability analysis of landfill is relatively conservative.A potential failure phase with a minimum safety factor cannot simply be determined by comparison of the values of inner friction angles and cohesions for a multilayer liner.The safety factor increases with the increase of inner friction angle and cohesion of the liner interface.The cohesion of the liner interface seriously affects the safety factor,especially for a liner interface with inner a low friction and high apparent cohesion.