中文摘要：

在考虑桩土相互作用的基础上,对确定合理桩间距的土拱的形成过程和成拱条件进行分析。根据桩受到的侧摩阻力等于桩间滑坡推力的平衡条件,提出同时存在桩侧土拱和桩后土拱,其拱厚为桩侧实际拱厚和桩后有效拱厚之和,在此基础上建立滑坡推力与抗滑桩相互作用的土拱受力模型,推导出临界桩间距的计算公式,最后通过算例进行验证,计算结果较为合理。研究结果表明：同时考虑桩侧土拱和桩后土拱比较合理。

英文摘要：

On the basis of considering the interaction between the pile and soil,the formation process and corresponding conditions of soil arch were analyzed to determine the reasonable pile spacing. According to the equilibrium condition that the side friction force exerted on the pile is equal to the landslide thrust force,soil arch in the pile side and soil arch behind the pile were proposed and existed at the same time. The total arch thickness equates to the sum of above two soil arch. On this basis,the soil arch model under pressure was established with the interaction of landslide thrust and anti-slide pile being taken into consideration,by which the computational formula of critical pile spacing was derived. The calculation results show the reasonability and validity through examples by considering the effect of lateral soil arch and soil arch behind the pile simultaneously. The results show that it is reasonable to take into account the pile side arch and the soil arch behind the pile at the same time.