不同降雨工况下红黏土边坡持水响应规律与稳定性分析

以江西区域内典型红黏土边坡为研究对象,基于岩土非饱和渗流理论,建立红黏土边坡有限元计算模型,对4种典型降雨工况下红黏土边坡稳定性进行分析。结果表明,降雨强度、降雨持续时间均是影响红黏土边坡稳定性的重要因素;前期为常态时,边坡各参数指标均维持在初始稳定状态;降雨开始后,边坡安全系数呈减小态势,岩土体强度和稳定性降低,边坡中土体的孔隙水压力变大,体积含水量升高;越接近地表的土体降雨入渗响应越强烈,边坡不同位置处土体的降雨入渗影响程度依次为:坡肩>坡顶>坡面>坡脚>坡底;降雨入渗和互渗过程具有明显的滞后性,越靠近地表,孔隙水压力短期内变化越明显;土体干湿循环对边坡稳定性整体表现为负作用,且作用效果不可逆。

Water Holding Response and Stability Analysis of Red Clay Slope under Different Rainfall Conditions

Taking the typical red clay slope in Jiangxi as research object and based on the unsaturated seepage theory of rock and soil,the finite element calculation model of the red clay slope is established to analyze the stability of the red clay slope under four typical rainfall conditions.The results show that,(a)both rainfall intensity and duration are important factors affecting the stability of red clay slope;(b)when the initial stage is normal,all the parameters of the slope remain in the initial stable state;(c)after the rainfall,the safety factor of slope decreases,the strength and stability of rock mass decrease,the pore water pressure of soil mass increases,and the volume water content increases;(d)the closer the soil is to the surface,the stronger the rainfall infiltration response is,and the influence degree of rainfall infiltration of soil at different positions on the slope is in the order of slope shoulder>slope top>slope face>slope foot>slope bottom;(e)the rainfall infiltration and infiltration process have obvious hysteresis,the closer to the surface,the more obvious the change of pore water pressure in a short term;and(f)the dry-wet circulation of soil has a negative effect on the stability of slope,and the effect is irreversible.