全埋式抗滑桩合理桩间距确定方法探讨

Method for determining rational spacing between adjacent embedded anti-slide piles

基于已有的桩间土拱简化计算模型,利用传递系数法确定作用于单位厚度土拱上的线分布压力q。考虑跨中截面前缘土体实际处于三向受压状态,由此建立土体抗剪强度条件,并在此基础上,提出以桩间静力平衡条件、跨中截面前缘土体抗剪强度条件以及拱脚处截面强度条件确定桩间距,推导出符合工程实际的桩间距计算公式。通过具体的工程实例,阐述抗滑桩桩间距的计算过程,得到比较合理的计算结果;进行距宽比L/b影响参数的敏感性分析,研究结果表明:在其他因素不变的情况下,边坡稳定系数Fsd的选取,对距宽比L/b的取值有显著影响。桩周土体的黏聚力c对距宽比L/b的取值有较大影响,内摩擦角φ对距宽比L/b值有影响,但影响程度较弱。

Using the transfer coefficient method,the linearly distributed pressure q acting on the soil arch per unit thickness were determined based on the existing simplified calculation model of soil arch between piles.Considering the fact that the front soil of the mid-span section is in triaxial compression,the strength criterion of the soil was established.On this basis,a calculation formula for rational spacing between adjacent anti-slide piles that conforms to the actual engineering situation was derived according to the static equilibrium condition between piles,the shear strength condition of the soil at the front edge of the cross section and the section strength condition at the arch foot.Then,a calculation process to determine rational spacing between adjacent anti-slide piles was demonstrated with the engineering practice,and the reasonable calculation results were obtained.The sensitivity of L/b to those influencing parameters was analyzed and it was found that without consideration of other factors,the selection of the stability coefficient Fsd has a significant effect on the value of L/b.The cohesion c of the soil around the pile has a great influence on the value of L/b,and the internal friction angleφalso has an effect,but rather small,on the L/b value.