不同降雨入渗条件下预应力锚索加固边坡稳定性分析

为了研究不同降雨条件下边坡安全系数及预应力锚索轴力变化规律,以省道S303沿线某边坡为研究对象,考虑土体饱和-非饱和渗流与非饱和强度理论,基于有限元分析,对不同降雨工况下的孔隙水压分布、锚索轴力及采用强度折减法计算的边坡安全系数变化规律进行了研究。结果表明: 降雨量一定时,降雨入渗范围随雨强增大而减小,暂态饱和区域随雨强增加而增大; 边坡在加固前后的安全系数均随降雨量增加而不断减小,采用预应力锚索加固能有效提高边坡安全系数,并减小降雨对边坡稳定性的影响; 随着降雨量增加,各锚索轴力均增大,当降雨量一定时,雨强越小,对应的锚索轴力提升幅度越大,靠近底部的锚索轴力对降雨最为敏感。

Stability Analysis for Slope Reinforced by Prestressed Anchor Cable with Different Rainfall Infiltration

In order to study the safety factor of slope and the changing rule of the axial force of the prestressed anchor cable under different rainfall conditions, the slope along the provincial highway S303 was taken for study. Taking theories of saturated-unsaturated seepage and unsaturated strength of the soil into consideration, the pore water pressure distribution, the axial force of the anchor cable, and the changing rule of the slope safety factor calculated by the strength reduction method under different rainfall conditions were studied based on the finite element analysis. The results show that when the amount of rainfall is constant, the range of rain infiltration decreases with the increasing of rainfall intensity, and the transient saturation area increases with the increasing of the rain intensity. The safety factor of the slope before and after the reinforcement decreases continuously with the increasing of the amount of rainfall, and the reinforcement with prestressed anchor cable can effectively improve the safety factor of the slope and reduce the impact of rainfall on the stability of the slope. As the amount of rainfall increases, the axial force of each anchor cable increases. When the amount of rainfall is constant, the lower the rainfall intensity, the greater the corresponding increase in the axial force of the anchor cable, and the axial force near the bottom of anchor cable is most sensitive to the rainfall intensity.