混凝土防渗墙对坝坡稳定作用机理的有限元分析

Simulation of working mechanism of concrete cut-off wall on stability of earth-rock dam by FEM

土石坝中建设防渗墙后，墙身会对坝体的渗流场和应力场产生一定的隔断作用，从而改变了相应的渗流场和应力场，对坝坡的整体稳定产生影响。依托大型非线性有限元软件ABAQUS，运用有限元强度折减法，对增建防渗墙前后的上、下游坝坡稳定安全系数进行比较分析，并引入计算收敛、土体位移、塑性贯通等3种失稳评价标准对比分析坝坡的安全系数。分析得出：建设防渗墙后，上游坝坡的稳定安全系数有所降低，下游坝坡稳定安全系数增加，从而使得整个坝体的稳定性得到提高。

As the lower permeability of the cut-off wall, the stress field and the seepage field of the slope would change after the cut-off wall is built. And the affect of the cut-off wall on the slope stability exists definitely. In order to analyze the mechanism of concrete cut-off wall working on the stability of the earth-rock dam, the strength reduction finite element method is adopted, in accordance with the ABAQUS. Besides, the difference and validity of the evaluating methods are analyzed by comparing to the three kinds of evaluating standard such as calculation, displacement and plastic through areas. The result reveals that the stability safety factor of the downstream slope increases while the upstream slope decreases after building a cut-off wall.