基于位移控制的双排桩桩后滑坡推力计算方法

Method for calculating landslide thrusts behind double-row piles based on displacement control

工程实践中,普遍以极限状态下的传递系数超载法获取单排桩桩后滑坡推力后再人为分配双排桩桩后滑坡推力,这与实际处于非极限状态的前后排桩的受力情况不符。从桩土变形协调出发,考虑位移与土拱效应之间的相关关系,结合莫尔圆坐标平移法和斜微分单元法,建立了基于竖向土拱理论和水平土拱理论的非极限状态下双排桩桩后滑坡推力的计算方法。与室内离心模型试验结果相比,前排桩桩后土体位移7,21 mm对应的前排桩桩后滑坡推力理论值与实测值基本相等,而后排桩桩后滑坡推力理论值与实测值误差为1.08%,6.42%,一定程度上说明了本方法的合理性和适用性。计算方法可以为任意桩后土体位移下双排抗滑桩桩后滑坡推力的计算和设计提供理论依据。

In engineering practices,the transfer coefficient overload method in the limit state is generally used to obtain the landslide thrusts behind one-row piles,and then the landslide thrusts behind double-row piles are manually distributed,which is inconsistent with the actual bearing forces behind the front-and rear-row piles in the non-limit state.Based on the coordination of pile-soil deformation,considering the correlation between displacement and soil arching effects,combining with the Mohr's circular coordinate translation method and the inclined differential element method,a method for calculating the landslide thrusts behind double-row piles in non-limit state is established based on the vertical soil arching theory and the horizontal soil arching theory.Compared with the indoor centrifugal model test results,the theoretical and measured landslide thrusts behind the front-row piles compatible with the soil displacements of 7 mm and 21 mm are basically the same,and the error between the theoretical and measured landslide thrusts behind the rear-row piles are 1.08%and 6.42%,which shows the rationality and applicability of the proposed method to a certain extent.The proposed method may provide a theoretical basis for determining the landslide thrusts behind double-row piles compatible with any soil displacement.