基于土拱效应下的地震作用与抗滑桩桩间距关系分析

An analysis of the relationship between seismic action and pile spacing of anti-slide piles based on soil arch effect

基于抗滑桩桩间土土拱效应,建立在地震作用下土拱效应的力学分析模型,在Mononobe-Okabe理论的基础上,将土拱作用等效为挡土墙作用,提出在一定地震设防烈度下土拱面上水平地震力的计算方法;在考虑滑坡推力和地震力两种外力作用下,依据桩间土在极限平衡状态下的静力平衡条件和强度条件,得出桩间净距理论计算公式。工程实例和系列试算表明,同等条件下,考虑地震作用比不考虑地震作用桩间净距要减小4%~23%,由此得出不同抗震设防等级下桩间净距计算的折减系数和桩间净距直接折减计算公式,以指导抗滑桩工程设计。

Based on the soil arch effect among anti-slide piles,the mechanics analysis model of soil arch effect for seismic action is established.On the basis of the Mononobe-Okabe theory and assuming that the soil arch effect is equivalent to retaining wall effect,the calculation method of the horizontal seismic force in the soil arch surface is presented under the seismic fortification intensity.According to the static equilibrium condition and strength condition of piles soil in the limit equilibrium state,the landslide thrust and seismic force is considered and the theoretical calculation formula of spacing between piles are otabined.Under the same conditions,engineering examples and series of trial show that spacing between piles reduce from 4% to 23% when the seismic action is considered.The calculation formula of direct reduction factor and reduction coefficient for spacing between piles in different seismic fortification levels are attained.