库水位变化对库岸边坡稳定性的影响

在假定坡体孔隙水水位为水平线且不考虑渗透作用影响的基础上,基于极限平衡法考察了水位上升及下降的快慢对边坡安全系数的影响。对比计算表明:在水位缓慢变化即坡体内外水位线等高的条件下,边坡的安全系数随着水位坡高比的增大先略减小后急剧增大,且在水位坡高比为0.3处取得最小值,在边坡完全淹没于水中时取得最大值。当边坡完全淹没于水中后,水位高于坡顶的多少对边坡安全系数没有影响;在水位骤降或陡升条件下,相同库水位对应的边坡安全系数基本上均小于水位缓慢变化情况下的安全系数,故工程实际中无论是排水还是蓄水,都应尽量保持水位缓慢变化,这样才能使边坡处于较安全的状态。

The Influence of Water Level Fluctuation on the Bank Slope Stability

Based on assumption of the pore water level is horizontal line and no seepage occurred in the slope,the influence of water-level fluctuation on stability of slope is presented through limit equilibrium method.It is shown that the factor of safety(FOS) of slope changes from slow decrease to rapid increase with water level slow raise,which get minimum value when ratio of water level-height of slope at 0.3,on the contrary,which get maximal value when water level as height as slope.There is no influence on FOS when the water level higher than slope.Further more,the FOS became less at water level rapid drawdown or rapid raise up than slow fluctuation.In order to avoid failure of slope,it is advised that water level fluctuated as slowly as human could controlled.