基于非稳定渗流有限差分的库岸滑坡稳定分析

三峡水库蓄水及水位波动,将极大地改变库岸滑坡体内的水文地质条件,库水位骤降和暴雨入渗是诱发滑坡的主要因素。目前,库水位骤降时的滑坡稳定性评价是滑坡防治中的一个难题。根据三峡水库水位调控方案,以某库岸滑坡为实例,利用有限差分法模拟库水位从175 m骤降至145 m时各时段的滑坡暂态渗流场,将计算得到的暂态水压力分布用于滑坡的稳定分析,建立了渗透力作用下滑坡稳定性评价的不平衡推力法,探讨不同工况下滑坡体稳定性变化规律。研究表明:库水位下降时,坡体稳定性先减小后增大,且在库水位降低至160 m左右时滑坡的稳定性达到最低值;当暴雨强度为200 mm/d时,该库岸滑坡的临界降速1 m/d。该成果将为库区滑坡治理提供科学依据。

The Stability Analysis of Coast in Reservoir's Bank Based on Non-Steady Seepage's Finite Difference

The sluice and water level's fluctuation will change the hydrographic geological conditions in coast of reservoir's bank greatly.The abrupt reduce of water's level and show's permeance is the main cause of coast.The assessment on coast's stability as the abrupt reduce of water's level is a great problem for coast's prevention.The paper takes one reservoir's bank coast as an example,uses finite difference to imitate the coast's seepage field when the water level drops down from 175 m to 145 m,and analyzes the coast's stability based on the calculated water pressure distribution,and sets up the imbalance thrust method of coast's stability assessment under the seepage.The research tests to be: when the water level drops down,the slope's stability decreases first and increases later,and reaches the minimum when water level drops to 160 m.When the show's intensity reaches 200 mm/d,the critical speed of the reservoir's bank coast reduces to 1 m/d.The achievement can provides some scientific reason for the prevention of reservoir's bank coast.