考虑剪胀与软化的接触面弹塑性模型  

ELASTO-PLASTIC CONSTITUTIVE MODEL OF INTERFACE INCORPORATING STRAIN SOFTENING AND DILATANCY

作　　者：彭凯[1,2,3] 朱俊高[2] 冯树荣[1] 蔡昌光[1] 朱晟[3] 

机构地区：[1]中国水电工程顾问集团中南勘测设计研究院,湖南长沙410014 [2]河海大学岩土工程科学研究所,江苏南京210098 [3]河海大学水工结构研究所,江苏南京210098

出　　处：《岩石力学与工程学报》2013年第S2期3979-3986,共8页Chinese Journal of Rock Mechanics and Engineering

基　　金：水利部公益性行业科研专项经费项目(200801133);国家自然科学基金资助项目(50825901);"十一五"国家科技支撑计划课题(2008BAB29B02)

摘　　要：采用大型单剪仪进行粗粒料与混凝土接触面在混合土泥皮(膨润土中掺入水泥)条件下的剪切试验,揭示混合土泥皮条件下接触面的力学特性与机制。试验结果表明,存在混合土泥皮时,接触面表现出明显的剪胀及应力–应变软化现象。峰值强度以及发生剪胀所对应的剪应变与法向应力大小有关,相同法向应力下,峰值强度所对应的剪应变滞后于产生剪胀的位置。为反映接触面的这一变形特性,基于广义位势理论,建立考虑剪胀以及应变软化的接触面弹塑性本构模型。利用塑性状态方程取代传统屈服面,采用分段函数,对剪应力与剪应变关系曲线和法向应变与剪应变关系曲线均用双曲线函数以及似正态函数分别进行拟合,从而确定模型中的各个参数。结合部分试验结果表明,模型计算的剪应力与法向应变与试验值的误差分别在10.5%,12.7%以内,从而验证模型的合理性。The mechanical behaviors of the interface between coarse-grained soil and concrete are investigated by large-scale simple shear tests under conditions of mixed soil slurry(bentonite mixed with cement grout). The results indicate that phenomena of dilatancy and stress-strain softening are significant with presence of mixed soil slurry. The peak strength and the position where the dilatancy occurs are related to normal stress. The shear strain corresponding to the shear dilatation appears to be ahead of that corresponding to the peak value of shear stress under the same normal stress. In order to describe the interface deformation behavior,a elasto-plastic constitutive model of soil-structure interface in considering of dilatancy and strain softening is formulated in the framework of generalized potential theory;and plastic state equations are used to replace the traditional yield surface. The relation curves of shear stress and shear strain are fitted by a piecewise function composed by hyperbolic functions and resembling normal functions,as well as the relation curves of normal strain and shear strain. The entire model parameters can be identified by experimental tests. Combined with measured values,the maximum error between the results of shear stress and normal strain calculated by the model and the test values is within 10.5%and 12.7%respectively. So the validity of the model is verified.

关 键 词：土力学 单剪试验 混合土泥皮 广义位势理论 本构模型 

分 类 号：TU43[建筑科学—岩土工程]