A modified creep index and its application to viscoplastic modelling of soft clays  

作　　者：Qi-yin ZHU Ze-xiang WU Yan-ling LI Chang-jie XU Jian-hua WANG Xiao-he XIA 

机构地区：[1]Department of Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China [2]School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, China [3]Research Center of Coastal and Urban Geotechnical Engineering, Zhejiang University, Hangzhou 310058, China

出　　处：《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》2014年第4期272-281,共10页浙江大学学报（英文版）A辑（应用物理与工程）

基　　金：Project supported by the National Natural Science Foundation of China （Nos. 41240024, 41372285, 41272317, 51278449, and 51238009）, the Research Fund for the Doctoral Program of Higher Education of China （No. 20110073120012）, and the European Project CREEP （PIAPP-GA-2011-286397）

摘　　要：Conventional consolidation tests on reconstituted specimens of numerous natural soft clays show a decreasing of creep index Cae with increasing soil density. Based on all selected and conducted experimental results, a modified creep index Cae＊ defined in double logarithmic plane lge-lgt, was plotted for various clays, from which Cae＊ can be assumed as a constant for different soil densities. Then, the modified creep index was applied to a newly developed elastic viscoplastic model. In this way, the modified creep index Ca＊ can naturally take into account the nonlinear Cae revealing the influence of soil density in the soil assemblies without additional parameters. Finally, the enhanced model was incorporated into the finite element code ABAQUS and used to simulate a consolidation test and a test embankment. The improvement of simulations by the modified creep index was highlighted by comparing simulations using the conventional creep index Cae.研究目的:提出一个更优的描述黏土非线性蠕变的方法。创新要点:1.提出了一个修正的蠕变系数,该系数与土体的密度相关,物理意义明确;2.将修正的蠕变系数嵌入到新开发的一个黏塑性模型中,实现了基于ABAQUS的本构二次开发;3.为工程实例的计算提供更为有效的模型。研究方法:1.总结广泛的调查土体蠕变试验结果,提出修正的蠕变系数(图3);2.给出修正的蠕变系数表示方法以及力学特性(图4);3.将所提系数嵌入到有限元程序中,验证了其准确性(图5)。重要结论:1.修正的蠕变系数可以很好地描述软黏土蠕变系数随孔隙比变化的规律;2.通过工程案例证实了修正系数的优越性。

关 键 词：Clays CREEP Consolidation test EMBANKMENT Finite element method VISCOPLASTICITY 

分 类 号：TP391.7[自动化与计算机技术—计算机应用技术] TU37[自动化与计算机技术—计算机科学与技术]