土的统一硬化函数的构造
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摘要
弹塑性本构模型中的硬化函数在加载条件下应该与应力路径无关.本文基于两条正交的加载路径(即等平均正应力剪切和等向压缩)下的土的变形规律,构造了能够统一地描述剪缩和剪胀特性的硬化函数,称为统一硬化函数.然后根据格林公式和试验数据,分别从理论和试验的角度验证了统一硬化函数在加载条件下的应力路径无关性.最后通过与各种加载应力路径下黏土、砂土的应力应变关系的试验结果进行对比,进一步证明了统一硬化函数及其统一硬化本构模型的合理性.
The hardening law in an elastoplastic constitutive model should be independent of the stress path for loading conditions. Based on the deformation behavior of soils along two orthogonal stress paths(i.e., constant mean stress shear path and isotropic compression path),a new hardening law, unified hardening law, is proposed to describe the shear contraction and dilatancy in an identical framework.Against Green's Formula and test data, we prove that the unified hardening law meets the requirement on the independence of loading path, theoretically and experimentally. The constitutive model developed by employing the unified hardening law is further verified by comparing it with the measured stress-strain relation of clay and sand under different loading paths.
The hardening law in an elastoplastic constitutive model should be independent of the stress path for loading conditions. Based on the deformation behavior of soils along two orthogonal stress paths(i.e., constant mean stress shear path and isotropic compression path),a new hardening law, unified hardening law, is proposed to describe the shear contraction and dilatancy in an identical framework.Against Green's Formula and test data, we prove that the unified hardening law meets the requirement on the independence of loading path, theoretically and experimentally. The constitutive model developed by employing the unified hardening law is further verified by comparing it with the measured stress-strain relation of clay and sand under different loading paths.
引文
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2 Roscoe K H, Burland J B. On the generalized stress-strain behaviour of ‘wet clay’. In:Engineering Plasticity. Cambridge at the University Press,1968. 535–609
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7 McDowell G R. A simple non-associated flow model for sand. GM, 2002, 4:65–69
8 黄文熙,濮家骝,陈愈炯.土的硬化规律和屈服函数.岩土工程学报, 1981, 3:19–26
9 Yao Y P, Sun D A, Matsuoka H. A unified constitutive model for both clay and sand with hardening parameter independent on stress path.Comput Geotechnics, 2008, 35:210–222
10 姚仰平. UH模型系列研究.岩土工程学报, 2015, 37:193–217
11 Nakai T, Matsuoka H. A generalized elastoplastic constitutive model for clay in three-dimensional stresses. SOILS Found, 1986, 26:81–98
12 Nakai T. An isotropic hardening elastoplastic model for sand considering the stress path dependency in three-dimensional stresses. SOILS Found,1989, 29:119–137
2 Roscoe K H, Burland J B. On the generalized stress-strain behaviour of ‘wet clay’. In:Engineering Plasticity. Cambridge at the University Press,1968. 535–609
3 Hashiguchi K. Subloading surface model in unconventional plasticity. Int J Solids Struct, 1989, 25:917–945
4 Dafalias Y F. Bounding surface plasticity. I:Mathematical foundation and hypoplasticity. J Eng Mech, 1986, 112:966–987
5 Whittle A J, Kavvadas M J. Formulation of MIT-E3 constitutive model for overconsolidated clays. J Geotechnical Eng, 1994, 120:173–198
6 Lade P V. Elasto-plastic stress-strain theory for cohesionless soil with curved yield surfaces. Int J Solids Struct, 1977, 13:1019–1035
7 McDowell G R. A simple non-associated flow model for sand. GM, 2002, 4:65–69
8 黄文熙,濮家骝,陈愈炯.土的硬化规律和屈服函数.岩土工程学报, 1981, 3:19–26
9 Yao Y P, Sun D A, Matsuoka H. A unified constitutive model for both clay and sand with hardening parameter independent on stress path.Comput Geotechnics, 2008, 35:210–222
10 姚仰平. UH模型系列研究.岩土工程学报, 2015, 37:193–217
11 Nakai T, Matsuoka H. A generalized elastoplastic constitutive model for clay in three-dimensional stresses. SOILS Found, 1986, 26:81–98
12 Nakai T. An isotropic hardening elastoplastic model for sand considering the stress path dependency in three-dimensional stresses. SOILS Found,1989, 29:119–137