基于土拱效应的支护桩间距确定方法

Discussion on determination of spacing between retaining piles based on the soil arching effect

在分析桩间土体成拱效应的基础上,从均布荷载作用下抛物线土拱计算模型出发,利用合理拱轴线和起拱点处土体破坏面等几何特征,通过桩间土拱静力平衡条件与强度条件共同控制来确定桩间距,从而推导出支护桩的间距计算公式.公式表明:桩间距随着桩后土压力的增大而减小,却桩后土体粘聚力或内摩擦角的增大而增大.最后通过工程实例计算,得到了比较合理的结果,具有一定的工程参考价值.

Based on the analysis of the soil arching effect, starting from calculation model of parabolic soil arch under distributed loading, taking geometrical features of rational arch line and the failure surface of soil at the edge of arch foot to account, the static equilibrium equation and intensity condition of the soil arch were used to determine spacing between adjacent pile.Thus the rational calculation formula of spacing between adjacent piles was obtained.It is shown that the spacing is decreasing with increase of soil pressure behind piles and increasing with increase of cohesion or internal friction angle of soil behind piles. In the end, the calculation procedure of spacing between adjacent piles is illustrated by a practical project and the resuh is rational, and the method is of certain value for engineering application.