水泥土剪胀特性三轴试验与数值模拟验证  

Triaxial test and numerical simulation verification of dilatancy characteristics of cemented soils

作　　者：许胜才[1] 蔡军 甘彬宏 XU Shengcai;CAI Jun;GAN Binhong(College of Architecture and Electric Engineering,Hezhou University,542899 Hezhou,China)

机构地区：[1]贺州学院建筑与电气工程学院,贺州542899

出　　处：《应用力学学报》2023年第3期643-653,共11页Chinese Journal of Applied Mechanics

基　　金：广西自然科学基金资助项目(No.2018GXNSFBA281129);广西高校中青年教师基础能力提升项目(No.2018KY0559)。

摘　　要：水泥土材料在剪切破坏过程中常会产生剪胀现象,但目前基于Mohr-Coulomb强度理论的恒定剪胀角模型不能正确表达水泥土材料在变形破坏过程中的非线性体积变化行为。因此,根据不同水泥掺入比和围压条件下的水泥土三轴压缩试验,结合塑性力学理论,采用非线性拟合方法建立了能同时考虑单轴抗压强度、平均应力和等效塑性应变影响的剪胀角模型,并运用有限元技术进行了数值模拟验证。结果表明,水泥土三轴试验的应力-应变曲线呈软化型,水泥土发生破坏后会伴随着明显的体积膨胀。水泥土的剪胀行为通常用剪胀角来量化,考虑平均应力和等效塑性应变影响的剪胀角模型能够合理表达水泥土在峰后的非线性体积变化行为,模拟结果与试验结果具有较好的一致性。而将剪胀角取为恒定值会出现高估或低估剪胀效应的情况,不能正确反映水泥土峰后的非线性体积变化规律。The dilatancy usually occurs in cemented soils materials when it is at failure by shear,but the constant dilatancy angle model based on Mohr-Coulomb strength theory at present cannot correctly express the nonlinear volume change behavior of cemented soils materials during deformation and failure.Therefore,according to the triaxial test of cemented soils under different cement ratios and confining pressure conditions,combined with the theory of plastic mechanics,the model of dilatancy angle affected by the uniaxial compressive strength,equivalent pressure stress and equivalent plastic strain simultaneously is established with a nonlinear fitting method,and then,the model of the dilatancy angle is verified by numerical simulation using finite element technology.The results show that the stress-strain curves of the cemented soils triaxial test is a softening type,and an obvious volume expansion will be generated when the cemented soils is damaged.The dilatancy behavior of cemented soils is usually quantified by the dilatancy angle.The dilatancy angle model under the influence of equivalent pressure stress and equivalent plastic strain can reasonably express the nonlinear volume change behavior of cemented soils after the peak stress,and the simulation results are in good agreement with the test results.However,if the dilatancy angle is taken as a constant value,the dilatancy effect will be overestimated or underestimated,and it cannot correctly reflect the law of nonlinear volume change of cemented soils after the peak stress.

关 键 词：水泥土 三轴试验 体积膨胀 剪胀角模型 

分 类 号：TU411[建筑科学—岩土工程]