循环荷载下路基红黏土临界应力水平分析  

Analysis of critical stress level of subgrade red clay under cyclic loading

作　　者：廖化荣[1,2] 汤连生[1] 刘增贤 张庆华[1,2] 

机构地区：[1]中山大学地球科学系,广州510275 [2]中山大学应用力学与工程学系,广州510275 [3]广东省公路建设有限公司,广州510600

出　　处：《岩土力学》2009年第3期587-594,共8页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.40872205;No.50279056);全国高等学校博士学科专项科研基金资助项目(No.20070558032);广东省自然科学基金资助项目(No.07003738);广东省科技计划资助项目(No.2008B030303009;No.2004B32801002;No.2003C33301)

摘　　要：根据设计改装的循环动单轴压缩试验,研究不同含水率、不同轴向应力水平、不同循环加载次数、不同应力加载路径条件下路基土的塑性力学行为,并结合shakedown概念,界定了循环动荷载作用下红黏土的安定界限(shakedown limit)和临界应力水平,系统地分析了影响循环动荷载作用下路基土力学行为的因素和永久变形的发展趋势,以及路基土在循环载荷作用下的力学行为发展规律。通过试验结果的分析,把红黏土的塑性变形分为稳定、破坏和临界3个阶段,并按3个阶段划分出可接受状态和不可接受状态,由此确定路基红黏土在循环荷载作用下的临界应力水平为41.8%。The shakedown and plastic behaviors of cohesive subgrade soil under cyclic loading are described. Based on the shakedown concept, various mechanical behaviors of subgrade red clay are discussed by repeated loading tests. The tests are performed with various conditions of subgrade soil, including different moisture contents, stress levels, numbers of repeated loadings and stress paths. According to the test results, the factors responsible for various mechanical behaviors of subgrade soil are analyzed in detail. The influence factors of the subgrade red clay mechanical behavior under cyclic loading and its permanent deformation trend as well as the mechanical behavior development rules are also analyzed systemically. The shakedown limit and critical stress level of subgrade red clay under cyclic loading with different moisture contents are presented. The plastic mechanical behavior can be divided into three phases： stable, failure and critical phrases, which are further divided into accepted condition and unaccepted condition. The critical stress level of subgrade red clay under cyclic loading is 41.8 %.

关 键 词：循环荷载 临界应力水平 安定界限 塑性行为 路基红黏土 永久变形 

分 类 号：TU446[建筑科学—岩土工程]