抗滑桩水平地震作用修正系数分析——汶川地震典型抗滑桩破坏工点分析

桩板墙是一种重要的新型支挡结构,已被广泛应用于边坡加固。过去规范中针对桩板墙采用的设计方法主要是拟静力法,较少涉及动力设计方法。选用汶川地震中的典型抗滑桩板墙工点,利用有限元软件ABAQUS对其进行分析。计算中选取"5.12"汶川地震卧龙台站记录作为激励,分析得到抗滑桩的弯矩、剪力、土压力分布等,并把分析结果与规范结果进行比较。比较结果表明,当采用规范计算时,地震综合影响系数应取0.4才能使工程满足设计要求。在此基础上,将汶川波的PGA(峰值地震动加速度)折换到7度(0.1g)、8度(0.30g)、9度(0.40g),分别对抗滑桩进行分析,将分析结果与规范对比发现,当按照规范计算时,地震综合影响系数分别取0.30(7度)、0.35(8度)、0.40(≥9度)时,能保证工程设计要求。

Seismic analysis of horizontal seismic coefficient of lateral loaded pile

Lateral loaded pile is a type of widely used retaining structures for stabilizing slope.Although various static design method for lateral loaded pile are recommended in design codes,few seismic design methods for the pile were developed in the past.In this paper,the deformation and load acted on the lateral loaded piles with 3 degree of tilt caused by the ground shaking from the 2008 Wenchuan earthquake are analysed by using software ABAQUS.To truly obtain the deformation and load of the pile,back-analysis and trial and error approaches are taken and measured pile displacements are used as control criteria.By using the back-analysis,we get the bending moment and shear force of the piles and earth pressure distribution on the piles.By compared with the values recommended from Chinese code,our results show that seismic coefficient of 0.4 can work very well for evaluating seismic response of the piles subjected to the 2008 Wenchuan earthquake.On the basis,we re-analyze the seismic response of the lateral loaded piles when subjected to PGA=0.1g(7 degrees),0.3g(8 degrees) and 0.4g(9 degrees) respectively.Results show that seismic coefficient of 0.3 is suitable for 7 degree,0.35 for 8 degree,0.4 for equal to and greater than 9 degree areas.In the paper,some impacted factors for lateral loaded pile design are also studed.Finally,a seismic design method for lateral loaded pile subjected to strong shaking is proposed.