膨胀性非饱和土本构模型的隐式和显式积分算法的比较  

Implicit and explicit integration schemes of a constitutive model for unsaturated expansive clays

作　　者：李舰[1,2] 王鹏月 海路 朱彦华 蔡国庆[1,2] LI Jian;WANG Pengyue;HAI Lu;ZHU Yanhua;CAI Guoqing(School of Civil Engineering,Beo＇ing Jiaotong University,Beijing 100044,China;National Demonstration Center for Experimental Civil Engineering Education,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京交通大学土木建筑工程学院,北京100044 [2]北京交通大学土木工程国家级实验教学示范中心,北京100044

出　　处：《岩石力学与工程学报》2018年第7期1731-1740,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金青年基金项目(51608033);中央高校基本科研业务费专项资金项目(2016RC043);北京交通大学大学生科研训练资助项目(170130049)~~

摘　　要：对比膨胀性非饱和土本构模型的隐式和显式积分算法的精度和收敛性。该模型区分了膨胀性非饱和土宏观、微观孔隙的力学行为间及持水特性间的差异,并考虑力学与持水行为间的相互影响。模型较为复杂,建立过程中采用边界面理论、多重塑性机制、多个硬化参数、耦合硬化方程等。利用Euler向前算法,并结合自动分步技术及多重塑性机制发生判断方法,对该模型提出一种显式应力积分算法。其次,利用该算法及已有的隐式算法对不同计算步长的应变控制试验进行计算及对比,以此讨论2种算法的精度和收敛性。对比结果为复杂模型的应力积分算法的选取提供了依据。Comparative studies on the accuracy and convergence of implicit and explicit integration schemes of a constitutive model for unsaturated expansive clays are conducted. The differences and interactions between mechanical and water retention behaviours of macrostructure and microstructure are considered in the model. The model is rather complex due to the adoption of bounding surface theory,multi-plastic mechanism,multiple hardening parameters,coupling hardening law,etc. Based on the Euler forward method,an explicit integration scheme combining an automatic sub-stepping scheme with a method to determine the number of active plastic mechanisms is proposed. Comparisons on the accuracy and convergence of the explicit integration scheme and existing implicit integration scheme are carried out according to the calculated results with different strain increment size on control-strain tests,which provides a basis for selecting the stress integration scheme of complex models.

关 键 词：土力学 非饱和土 双尺度结构 多重塑性机制 隐式积分算法 显式积分算法 

分 类 号：TU43[建筑科学—岩土工程]