降雨条件下体积含水率对堆积体边坡渗流特性的影响研究

INFLUENCE OF VOLUMETRIC WATER CONTENT ON SEEPAGE CHARACTERISTICS OF SLOPE DEPOSIT UNDER RAINFALL CONDITIONS

锦屏水电站对外交通专用公路K48＋722～800段滑坡受降雨影响明显，其深层稳定性关系到工程安全。本文依据实验数据，采用Fredlund-Xing方法拟合出滑坡体材料的土水特征曲线，以体积含水率反应土体初始湿润状态，研究了降雨条件下边坡压力水头的演化规律，体积含水率对压力水头以及边坡稳定性的影响。结果表明，降雨初期，坡体表面以及滑面处压力水头先增大，并向坡体内部逐渐扩展。雨停一段时间后，坡体表面以及前缘区压力水头逐渐消散，滑面后缘局部地区压力水头会有所升高，压力水头随着体积含水率的增大而增大。体积含水率较小时，在一定的时间内，边坡的稳定性系数先保持稳定，后缓慢降低；当体积含水率较大时，雨停一定时间后边坡的稳定性系数会出现上升的趋势。

The highway slope of K48 + 722 ~ 800 in Jinping hydropower station is greatly affected by rainfall. The deep stability of this slope is related to the safety of the station project. On the basis of the experimental data,this paper uses Fredlund-Xing method to fit the SWCCs of the slope soils. The volumetric water content is used to represent the initial moist station of the soil. Then the evolution rules of pressure head,the influence of volumetric water content on pressure head and slope stability under rainfall conditions are researched numerically. The results show that,the pressure head at the slope surface and slip increases gradually at early rains. Then the area with increasing pressure head can expend toward the inside of slope body. For a period of time after rainfall,the pressurehead of the slope surface and inferior region dissipates,while the pressure head of partial trailing area of slip increases. The pressure head would increase with the volumetric water content. And when the volumetric water content is little,the stability coefficient of slope can keep unchanging for a certain time and then slowly decreases.However,when volumetric water content increases,the stability coefficient of the slope can have an upward trend after rainfall.