振动条件下EPS缓冲层对挡土墙受力与变形影响的水平条分法模型研究  

Horizontal slice method for force and displacement analysis of EPS geofoam seismic buffers for rigid retaining walls

作　　者：汪益敏[1] Bathurst R J 

机构地区：[1]华南理工大学,广东广州510640 [2]Royal Military College of Canada,Kingston Ont.,

出　　处：《土木工程学报》2008年第10期73-80,共8页China Civil Engineering Journal

基　　金：国家留学基金(2004844009)

摘　　要：基于考虑时间因素的显示有限差分原理,提出水平条分法数值模型,分析铺设在挡土墙背的EPS(Expanded Polystyrene)土工泡沫缓冲层对振动作用下挡土墙的受力与变形的减震作用。模型中EPS缓冲层为线弹性材料,墙背填土滑楔体被划分为若干个水平土层,每一个水平土层的边界受力与变形分别采用与应力相关的线性弹簧模拟。计算得出振动加速过程中挡土墙背不同高程位置各土条随时间而变化的压力和压缩变形值。以加拿大皇家军事学院岩土工程中心完成的3个室内缩小比例的EPS缓冲层挡土墙振动试验为计算实例,对比研究不同弹性模量的EPS缓冲层减震作用的理论计算结果和试验监测结果。研究结果显示,在水平振动加速度达到0.9g的整个加速过程中理论模型分析预测的沿挡土墙背高程分布的压缩变形以及最大压力与试验监测结果相当一致。该模型的提出,为分析和预测采用EPS土工泡沫作为抗震缓冲层的挡土墙受力和变形提供了可行的方法,对挡土墙的抗震设计有较好的应用价值。Based on an explicit time-marching finite difference approach, a multiple horizontal layer model is proposed to calculate the compression-load-time response of EPS geofoam seismic buffers placed against rigid walls to attenuate earthquake-induced dynamic loads. The seismic buffer is modeled as a linear elastic material. The soil wedge is divided into a number of horizontal slices, the boundaries of which are connected to a series of stress-dependent linear springs. The distributions and magnitudes of compressive displacement of and load on the EPS geofoam buffer are calculated. Three physical tests, carried out at the Royal Military College of Canada, are used to investigate the accuracy of the model. The numerical results and physical test results for the displacement of and load on EPS geofoam buffers with different elastic moduli are compared and analyzed. The model is shown to be capable of capturing the trends observed in three physical dwonscaled model shaking table tests carried out with similar boundary conditions and up to a base excitation level of about 0.9 g. Model predictions are shown to be in reasonable agreement with the physical test results. The model provides a possible method for analyzing and predicting the force and deformation distributions of EPS geofoam seismic buffers placed against rigid retaining walls.

关 键 词：振动力 EPS土工泡沫 挡土墙 水平条分法 理论模型 

分 类 号：U416.162[交通运输工程—道路与铁道工程]