胶结砂砾石料剪切二元强度准则与本构模型研究  

Bimodal strength criterion and constitutive model for cemented sand and gravel

作　　者：武颖利[1] 任红磊 郭万里 WU Yingli;REN Honglei;GUO Wanli(Geotechnical Engineering Department,Nanjing Hydraulic Research Institute,Nanjing 210024,China;Materials and Structural Engineering Department,Nanjing Hydraulic Research Institute,Nanjing 210024,China)

机构地区：[1]南京水利科学研究院岩土工程研究所,江苏南京210024 [2]南京水利科学研究院材料与结构研究所,江苏南京210024

出　　处：《岩土工程学报》2025年第3期516-524,共9页Chinese Journal of Geotechnical Engineering

基　　金：广东省水利科技创新项目(2024-01);中国科协青年人才托举工程资助项目(YESS20200361)。

摘　　要：为探究胶结砂砾石料复杂的力学特性,开展不同围压、不同掺量的胶结砂砾石料大型三轴剪切试验,并建立了适用于胶结砂砾石料的二元剪切强度准则和双屈服面本构模型。结果表明:(1)胶结砂砾石料具有一定的胶结力和结构性,宏观上表现出显著的软化、强剪胀等力学特性;(2)基于二元介质理论建立了剪切强度准则,该准则可描述不同胶凝掺量下的胶结砂砾石料的强度演化规律;(3)将剪切强度准则合理转化为本构模型中的剪切屈服面,并在修正剑桥模型基础上考虑材料的抗拉特性得到体积屈服面,同时本构模型重点描述了胶结砂砾石料的应变软化及强剪胀性;(4)推导了本构模型在一般应力状态下的刚度矩阵,并证明了其对胶结砂砾石料三轴剪切试验具有良好的拟合效果。该研究结果可为胶结砂砾石坝的应力变形计算提供更好的理论指导。In order to explore the intricate mechanical properties of the cemented sand and gravel(CSG),large-scale triaxial shear tests are conducted on the specimens with varying confining pressures and gel contents.A bimodal shear strength criterion and a double-yield surface constitutive model applicable to the CSG are established.The main conclusions are as follows:(1)The CSG exhibits a certain level of cohesive strength and structural integrity,demonstrating notable mechanical characteristics such as softening and pronounced shear dilatancy at the macroscopic scale.(2)The shear strength criterion,based on the binary medium theory,is developed to describe the evolution of strength in the CSG under varying gel contents.(3)The shear strength criterion is appropriately transformed into the shear yield surface within the constitutive model,and by considering the tensile resistance of materials a volumetric yield surface is established based on the modified Cam-clay model.Additionally,the constitutive model emphasizes to describe the strain softening and strong dilatancy of the CSG.(4)The stiffness matrix of the constitutive model is derived for the general stress states,and its excellent fitting with the triaxial shear tests on the CSG is demonstrated.The findings of this study can provide better theoretical guidance for stress-deformation calculations in CSG dams.

关 键 词：胶结砂砾石料 强度准则 应变软化 剪胀性 双屈服面模型 

分 类 号：TV641[水利工程—水利水电工程] TU452[建筑科学—岩土工程]