考虑固结过程的软土地基承载力数值分析  

Numerical analysis on bearing capacity of soft soil foundation with consideration of soil consolidation

作　　者：尹利强[1] 王元战[1] YIN Li-qiang;WANG Yuan-zhan(National Key Laboratory of Water Conservancy Engineering Simulation and Security,Collaborative Innovation Center for Advanced Ship and Deep-sea Exploration,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学水利工程仿真与安全国家重点实验室高新船舶与深海开发装备协同创新中心,天津300072

出　　处：《水道港口》2018年第4期477-482,共6页Journal of Waterway and Harbor

基　　金：国家自然科学基金(51279128);国家自然科学基金创新研究群体科学基金(51321065);交通运输部交通建设科技项目(2013328224070)

摘　　要：深厚软黏土地基在受到上部结构传递的荷载作用时将会发生进一步固结,进而影响软土地基的承载特性,因此考虑荷载作用下软土地基的固结特性对地基承载力分析有重要意义。文章以室内静三轴试验所得软黏土抗剪强度指标c、φ随固结度和静偏应力变化规律为基础,利用大型有限元软件ABAQUS,通过用户子程序USDFLD对土体材料进行二次开发,建立考虑土体抗剪强度指标随固结度和静偏应力变化的有限元模型,进而对重力沉箱式防波堤软土地基承载力进行数值分析。有限元计算结果表明:静偏应力作用下地基土体发生进一步固结,土体固结度随时间增长而增大,抗剪强度指标出现明显增长。依据极限承载力、允许变位的判别标准分别对软土地基承载力进行分析:伴随着土体的不断固结,两种判别标准下的承载力安全系数均明显增大,且后者计算结果相对安全,建议采用允许变位的判别标准来计算实际工程中的承载力安全系数。The thick soft clay foundation tends to continue consolidating under the applied load of the upper structure, which has a great influence on the bearing capacity of the foundation. Hence, considering the further consolidation due to the upper load, the analysis of the bearing capacity of soft clay foundation is of great significance. In this paper, based on the variation law of the soil indexes of soft clay under load action by laboratory test, the finite element software ABAQUS was used to make a secondary development for soil material by applying the user subroutine-USDFLD. The finite element model was built to consider the variation of shear strength index due to the consolidation degree and static deviator stress ; then the bearing capacity of the foundation was analyzed. The numerical analysis results show that the consolidation deglve of foundation soil increases with time under the static deviator stress, and the shear strength indexes increase obviously. The bearing capacity of foundation was analyzed according to the standard of ultimate bearing capacity and allowable displacement of structure. The safety coefficient for bearing capacity increases dramatically along with the consolidation of foundation soil, and a relatively safe calculation result is shown for the latter one, which is recommended to calculate the safety coefficient of the soft clay foundation.

关 键 词：地基承载力 抗剪强度指标 固结度 静偏应力 有限元分析 二次开发 

分 类 号：TU471.8[建筑科学—结构工程]