外荷载作用下软土压缩模量的动态演化规律研究  

Research on dynamic evolution law of compression modulus of soft clay under external loads

作　　者：周翠英[1,2] 林春秀[1,2] 林鲁生[3] 杨锡鎏[1,2] 

机构地区：[1]中山大学工学院,广州510275 [2]中山大学岩土工程与信息技术研究中心,广州510275 [3]深圳市水务局,深圳518036

出　　处：《岩土力学》2010年第7期2040-2044,共5页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.59809008;No.40672194);国家863计划课题(No.2007AA11Z112);广东省自然科学基金重点项目(No.013188;No.06104932);教育部博士学科点基金项目(No.4115260;No.20060558060);广东省科技攻关十五重点专项(No.2001B30803);广东市科技支撑计划项目(No.10A12051369);广东粤东高速公路实业发展有限公司委托项目(No.7101043);中山大学后备重点课题(No.1132169)

摘　　要：在软土地基的压缩性评价和变形计算中,压缩模量是一个重要的土性参数,目前一般是通过室内侧限压缩试验曲线得到,通常是一个常数。实际上,压缩模量在地基固结过程中会随着土体固结度的增加而逐渐增大,因此,探讨外荷载作用下软土压缩模量的变化规律显得十分必要。以珠江三角洲地区某高速公路代表性软土地基为研究对象,采集天然状态和超载预压后两种状态的淤泥质土样,分别开展不同压力条件下的室内固结试验,通过分析比较两种状态土样的试验数据,得出了两种状态下淤泥质土压缩模量随压力变化的定量关系和压缩模量随压力及时间演化的规律。在此基础上,结合天然状态和超载预压后的淤泥质土样在室内再压缩前后的微观结构图像,分析了两种状态下淤泥质土压缩模量随压力和时间演化的机理。从而为软土变形计算的参数合理取值提供了有用的参考,且对软基堆载预压过程中控制加荷速率和分级荷载的大小具有重要的现实意义。During the compression estimation and deformation calculation of soft ground, compression modulus is an important soil parameter which is generally obtained from compression curve of lateral confined compression test; and it usually is a constant. But actually, during the process of foundation consolidation, compression modulus will develop gradually along with the growing up consolidation degree; therefore, it is necessary to study the variation law of compression modulus of soft clay under external loads. Two kinds of silt soil samples of natural state and after overloading pre-compression were taken from a typical soft ground of a certain highway in Pearl River delta to carry out consolidation tests with different pressure levels respectively. By analyzing the experimental results, the quantitative relations between compression modulus and pressure of these two kinds of silt soil are obtained; and the evolution law of compression modulus with pressure and time is summarized. On this basis, combined with the microstmcture images of natural state and after overloading pre-compression silt soil samples before and atter indoor compression, the evolution mechanism of compression modulus with pressure and time of these two kinds of silt soil is analyzed. It provides a useful reference for giving reasonable values of deformation calculation parameters of soft clay and has important significance for controlling loading rate and various stages loads during the surcharge preloading process of soft foundation.

关 键 词：软土 压缩模量 固结试验 演化规律 

分 类 号：TU45[建筑科学—岩土工程]