坡地区域摩擦隔离桩作用机理及斜坡稳定性研究

Study on action mechanism of friction-isolated pile and slope stability in sloping area

为减小坡地区域桥梁基桩对边坡的不利影响,通过在潜在滑动面以上桩身进行摩擦隔离处理,利用ABAQUS有限元软件分析摩擦隔离桩的作用机理及斜坡稳定性。研究结果表明:四种情况下斜坡安全系数从小到大为:自然无桩<有桩有载<有桩有载且摩擦隔离<有桩无载;摩擦隔离桩的桩身最大内力(弯矩和剪力)位置与无摩擦隔离桩的位置相比下移,且下移至套筒底部附近位于稳定土层中;潜在滑动面以上的摩擦隔离桩桩侧净土压力和桩身侧摩阻力较小,保护了上部土体;一定桩长或桩径范围下,桩长或桩径尺寸与斜坡安全系数成正比,超过范围后将不再提高斜坡安全系数;坡中布桩安全系数最大,但坡中下部位置(L_x/L=13~12)布桩最佳。

In order to reduce the adverse impact of bridge piles in sloping area on slope stability,the friction isolation treatment is carried out on the pile body which above the potential sliding surface,and the mechanism of friction-isolated pile and slope stability are analyzed by ABAQUS.The results show that the safety factor of the slope varies from small to large in four cases:naturally no pile<pile is loaded<friction-isolated pile is loaded<pile is unloaded.The position of maximum internal force(bending moment and shear force)of friction-isolated pile is lower than the non-friction-isolated pile,and it is located in stable soil which is near the bottom of sleeve.The net earth pressure and side friction resistance of friction-isolated pile above the potential sliding surface are smaller,which protect the upper soil.In a certain range of pile length or diameter,the length or diameter of pile is directly proportional to the safety factor of slope,and it will not improve the safety factor of slope after exceeding the range.The safety factor of pile placement in the middle of the slope is the largest,but the pile placement in the middle and lower of the slope is the best.