饱和砂砾土动残余变形的新模型  

A New Residual Deformation Model of Saturated Sandy Gravel Under Cyclic Loadings

作　　者：赵凯[1] 蓝天 周建军[2] 孙田[1] 刘德洋 陈国兴[1] ZHAO Kai;LAN Tian;ZHOU Jianjun;WU Qi;SUN Tian;CHEN Guoxing(Institute of Geotechnical Engineering,Nanjing University of Technology,Nanjing,210009,China;State Key Laboratory of Shield Machine and Boring Technology,China Railway Tunnel Group Co,Ltd,Zhengzhou 450001,China)

机构地区：[1]南京工业大学岩土工程研究所,江苏南京210009 [2]中国中铁隧道集团有限公司,盾构及掘进技术国家重点实验室,河南郑州450001

出　　处：《应用基础与工程科学学报》2019年第5期1102-1114,共13页Journal of Basic Science and Engineering

基　　金：国家自然科学基金项目(51608267);国家863计划课题(2012AA041802,2012AA041803)

摘　　要：土体在循环荷载作用下的残余变形特性是进行土体地震永久变形分析的基础.利用GDS循环扭剪试验系统,针对5种级配的砂砾土,考虑含砾量、排水条件、有效固结应力、循环动应力比、渗透系数等因素的影响,进行了60个工况组合的循环三轴试验,研究了饱和砂砾土的动残余变形特性,结果发现:饱和砂砾土的动残余体应变与lg(1+N)呈明显的非线性关系;其他试验条件相同时,动残余剪应变随排水面增多、含砾量增大而减小,渗透系数对其影响不可忽略;动残余体应变随排水面数增多而增大,随含砾量的增大而减小.在沈珠江模型基础上,引入排水通畅指数概念,建立了一个新的饱和砂砾土动残余变形模型,该模型能较好地反映含砾量、排水条件、渗透系数对饱和砂砾土动残余变形特性的影响.The accuracy of numerical results of soil seismic permanent deformation depends on the rationality of soil residual deformation model.Using the Hollow Cylinder Apparatus(HCA),60 dynamic triaxial tests were performed on the saturated specimens to investigate the effects of gravel fraction,effective confining stress,cyclic stress ratio and permeability coefficient on the residual deformation characteristics of sandy gravel.5 different graded sandy gravels were chosen as specimens.The results indicate that there is an obvious nonlinear relationship between the residual volumetric strain and lg(1+N)(N is the number of cycles).When other conditions are fixed,the residual shear strain decreases while the residual volumetric strain increases with the increasing drainage faces,however,both of them decrease with the growing of gravel content.Notably,the effect of permeability coefficient on dynamic residual shear strain is not negligible.On the basis of the Shen’s model,a new residual deformation model for saturated sandy gravel was developed,in which a new concept of permeability index was introduced.The results show that the new model can well describe the influences of gravel fraction,drainage condition and permeability coefficient on residual deformation characteristics of sandy gravel.

关 键 词：砂砾土 动残余变形模型 排水条件 含砾量 排水通畅指数 

分 类 号：TU43[建筑科学—岩土工程]