加固膨胀土边坡的单排抗滑桩受力性能分析

根据边坡浅表层的膨胀力随深度变化模型,将膨胀力引入到抗滑桩受力分析及膨胀土边坡稳定性分析中。基于4类经典的边坡稳定性极限平衡条分法并考虑桩间局部土体对抗滑桩的摩阻作用,给出膨胀土边坡抗滑桩的剪力计算方法—在给定设计安全系数下以桩身剪力取得最大值为条件迭代计算,得到了是否考虑抗滑桩桩间土体摩擦作用的桩身剪力上、下边界值的解,以及在给定安全系数下的加桩边坡潜在最危险滑面位置的圆弧型滑面搜索算法。对云桂铁路一工点膨胀土路堑边坡实例分析结果表明:考虑膨胀力时桩身剪力较不考虑膨胀力时显著增大,膨胀力越大剪力也越大;若不考虑膨胀力剪力约降低80%~90%,偏于不安全;通过简化Bishop法、Morgenstern-Price法和Spencer法分析得到的抗滑桩剪力结果较为接近,而Fellenius法的计算结果则大于前三者,最大偏差约20%。

Analysis on Mechanical Performance of Single Row Stabilizing Piles for Reinforcing Expansive Soil Slope

According to the model of the expansive pressure varying with the depth,which located at the shallow surface of the slope,the expansive pressure was introduced into the stress analysis of the stabilizing pile and the stability analysis of the expansive soil slope.Based on the four classical limit equilibrium method of slope stability and considering the friction effect of local soil between adjacent piles against stabilizing piles,the shear force calculation method of stabilizing pile in expansive soil slope was derived.In the case of a specified factor of safety,the iterative calculation should under the condition that the maximum shear force of pile body was obtained.Additionally,the solutions of the upper and lower boundary values of the pile body shear force with or without considering the soil friction between the stabilizing piles were obtained.Moreover,the search algorithm of arc-shaped sliding surface at the location of the most potentially dangerous sliding surface of the pile slope was obtained,under the given safety factor.The analysis results of the expansive soil cutting slope in Kunming-Nanning railway construction site show that the pile shear force increases significantly when the expansive pressure is considered,and the larger the expansive pressure is,the larger the shear force is.If the expansion force is not considered,the shear force will be reduced by 80%~90%,which is unsafe.The results of shear force of stabilizing pile obtained by simplified Bishop method,Morgenstern price method and Spencer method are close,while the results of Fellenius method are larger than the first three,with the maximum deviation of about 20%.