设垃圾坝填埋场的三楔体滑动分析

THREE-PART WEDGE METHOD FOR TRANSLATIONAL SLIDING ANALYSES OF LANDFILLS RETAINED BY A TOE DAM

提出新建及扩建设垃圾坝填埋场的三楔体极限平衡分析法,给出安全系数的近似解,使得填埋场沿背部、底部及垃圾坝内坡处衬垫界面的三折线型滑动分析大为简化,发现其具有较好的工程适用性。该方法与精度较高的Spencer法所给出的计算结果吻合良好,且能考虑填埋体内摩擦角的影响。研究结果显示,衬垫界面的强度直接影响填埋体沿衬垫界面的稳定性,而填埋场各坡坡度、填埋场高度和宽度以及垃圾坝的高度对安全系数均有较大的影响。对扩建填埋场的分析结果表明,扩建填埋体沿新老场交界面的安全系数较低,在扩建填埋场的设计中应引起重视。另外,扩建填埋场的横向扩建宽度越大,则其界面安全稳定性越好。

The three-part wedge method for translational failure analyses of landfills retained by a toe dam was presented;and the approximate solution of the factor of safety was also given. With this approximate solution,analyses of the stability of new and expanded landfills along the back and bottom linings can be considerably simplified. Thus it is an acceptable method for the engineering application. Computed results by the proposed method are in good agreement with those by the Spencer′s method. Moreover,it can take into account the effect of the internal friction angle of the waste on the factor of safety. Parametric studies show that the interface strength of the lining determines the stability of the landfill along the lining. The angles of slopes,the height and width of the landfills and the height of the toe dam also greatly influence the sliding of the landfill along the lining. For the expanded landfill,more attentions should be paid to the failure along the intermediate lining between the existing and expansion wastes. Additionally,the wider the landfill expands horizontally,the better the stability along the intermediate lining is.