库水位骤降时坝体渗流场及坝坡稳定性分析

An Analysis of the Seepage Field and the Stability of Dam Slope During Rapid Drawdown of Reservoir Water Table

为了研究水位骤降时影响上游坝坡稳定性的因素,模拟坝坡在水位骤降时的渗流场及稳定性变化。基于土体渗透性,材料的非线性特性及水位下降率,利用有限元法对库水位变化下的渗流场进行瞬态分析,得出的自由水面线和孔隙水压力耗散等结果应用于上游坝坡稳定性分析,坝坡稳定分析采用极限平衡法。实例分析表明:计算区域渗流场变化滞后于水位下降的时间;坝体渗透系数越小,水位骤降对其稳定性的不利影响越显著;水位下降速率越大,上游坝坡稳定性降低越快。

In order to study the effect of water table drawdown upon the factors of upstream dam slope stability,it is necessary to simulate the seepage field and changes in stability in the case of dam slope in water table drawdown.Based on soil permeability non-linearity of materials and rate of water table,the finite element method is used to carry out the transient analysis of the seepage field in the case of changes in reservoir water table,whereby obtaining that the results of free water surface line and dispersion of pore water pressure,etc,can be used to analyze the upstream dam slope stability,but the limit equilibrium method is used to analyze the dam slope stability.The real example analysis indicates that the changes in seepage field in the calculated zone delay in time of reservoir water table drawdown,the smaller the osmotic coefficient of dam body is,the greater the effect of disadvantages of water table drawdown upon the stability is;the greater the rate of water table drawdown is,the faster the stability of upstream dam slope decreases.