基于流固耦合的某水库垂直防渗墙合理深度的确定

Determination of reasonable depth of vertical antiseep wall of a reservoir based on fluid-solid coupling

基于比奥固结理论,借助ADINA流固耦合模块和Slope/w进行数值模拟,计算得出渗流参量、竖向位移、抗滑稳定安全系数,探讨土石坝坝基中防渗墙的合理深度.研究表明:防渗墙的贯入度为0.6时,渗流量小于0.01倍的河道多年平均来水量;出逸坡降和防渗墙底部渗透坡降皆小于允许渗透坡降;上、下游坝坡抗滑稳定安全系数皆大于最小抗滑稳定安全系数,位移量满足规范要求.因此,防渗墙的贯入度0.6为该水库防渗墙的最优深度.此外,当防渗墙底部接触基岩时,渗流通道极小,局部水头损失大,该水头损失叠加到防渗墙底部的水头差上防渗墙底部渗透坡降出现极大值,工程中防渗墙应嵌入基岩3~5 m.

Based on the Biot’s consolidation theory,the earth-rock dam is numerically simulated by means of fluid-solid coupling module of ADINA and Slope/w;seepage parameters,vertical displacement,and safety factor of stability against sliding of dam slopes are calculated;the reasonable depth of vertical antiseep wall under earth-rock dam foundation is explored.The research result shows that when penetrativity of antiseep wall equals to 0.6,the seepage discharge will be less than one percent of average annual water inflow of river.Exit gradient and seepage gradient at bottom of cutoff wall will be less than permissive permeability gradient.Safety factor of stability against sliding of dam slopes at both upstream and downstream will be greater than the minimum safety factor against sliding,and the displacement will satisfied with the requirement of the standard as well.Therefore,the antiseep wall penetrative of 0.6 will be the optimal depth.In addition,seepage channel will be very narrow when antiseep wall is in contact with bed-rock,the local head loss will be large;when this head loss is added to the head difference at bottom of antiseep wall,the seepage discharge at bottom of antiseep wall will approach its maximum value,so that the antiseep wall should be embedded in bedrock from 3 to 5 m.