滨海相软土延拓邓肯–张模型的数值模拟研究  

NUMERICAL SIMULATION RESEARCH ON PROLONGATION DUNCAN-CHANG MODEL FOR SEASHORE SOFT SOIL

作　　者：俞缙[1,2] 李天斌[2] 郑春婷[1] 蔡燕燕[1,3] 涂兵雄[1] 穆康[1] 

机构地区：[1]华侨大学岩土工程研究所,福建厦门361021 [2]成都理工大学地质灾害防治与地质环境保护国家重点实验室,四川成都610059 [3]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221008

出　　处：《岩石力学与工程学报》2014年第A02期4271-4281,共11页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51374112);成都理工大学地质灾害防治与地质环境保护国家重点实验室开放基金项目(SKLGP2013K014);中国矿业大学深部岩土力学与地下工程国家重点实验室开放基金项目(SKLGDUEK1304)

摘　　要：引入控敛因子θ,提出能克服邓肯–张模型数学缺陷的延拓模型,证明邓肯–张模型是延拓模型在θ=2时的特例,并揭示延拓模型更适用于模拟具有强烈非线性变形行为的滨海相软土。基于传统的邓肯–张模型和新建的延拓模型,采用C++语言编制二维有限元程序,对滨海相软土常规三轴压缩试验进行数值模拟研究。研究结果表明:当初始切线模量和极限偏应力为定值时,控敛因子与延拓模型曲线的收敛速度呈负相关;延拓模型可通过改变控敛因子来模拟收敛速度大于或小于邓肯–张模型的应力–应变曲线;在轴向应变相同的情况下,减小控敛因子,会导致试样各单元的轴向应力值和中部单元的径向应变值增大,试样部分单元最小安全系数减小;同一围压下,控敛因子与体积应变呈负相关;围压越大,控敛因子对体积应变的影响也越大。The control convergence factor θ was introduced to propose a prolongation model which could avoid the mathematical defect of Duncan-Chang model. It is proved that the Duncan-Chang model is one exception of prolongation model with the value of θ equal to 2. The prolongation model is revealed to be more suitable for simulating seashore soft soil which has strong nonlinear deformational behavior. A two-dimensional finite element program was presented using the C＋＋ language based on the traditional Duncan-Chang model and the new prolongation model. Conventional triaxial compression tests of seashore soft soil were carried out using the new program. The results show that,θ is negatively correlated with the convergence rate of prolongation model curve when the initial tangential modulus and limit deviatoric stress were set. By changing the value of θ, the stress-strain curve with the convergence rate greater or less than that obtained from Duncan-Chang model can be derived from the prolongation model. With the same axial strain,the axial stresses of the whole specimen and the radial strains of the central units would increase with the reduce of the control convergence factor. So the minimal safety factor of the sample units would reduce. Under the same confining pressure,the control convergence factorwas negatively correlated with the volume strain change. For the same volume strain, the larger the confining pressure,the more significant influence the control convergence factor would be.

关 键 词：土力学 控敛因子 邓肯–张模型 延拓模型 滨海相软土 数值模拟 

分 类 号：TU44[建筑科学—岩土工程]