基于结构性黄土联合强度的邓肯–张非线性本构模型

基于Mohr–Coulomb强度准则建立的邓肯–张非线性本构模型可以较好地反映土体抗剪强度特性,但是不适宜反映土体的抗拉强度特性。为了合理反映结构性黄土的抗拉强度,首先,通过在邓肯–张非线性本构模型中引入联合强度准则,基于联合强度准则重新确定了土的强度(1 3?-?)f,从而对破坏应力比Rf进行了修正;然后,用修正后的破坏应力比Rf重新确定了切线变形模量Et;最后,用修正后的切线变形模量Et对切线泊松比νt进行了修正,从而建立了基于联合强度理论的邓肯–张模非线性本构模型,为邓肯–张非线性本构模型在结构性黄土边坡的稳定性研究中,合理考虑结构性黄土的抗拉强度特性的作用提供了一种新的方法和途径。

Duncan-Chang nonlinear constitutive model based on joint strength theory of structural loess

The Duncan-Chang nonlinear model based on the Mohr-Coulomb strength criterion can better reflect the shear strength characteristics of the soil, but it is not suitable to reflect the tensile strength characteristics of the soil. In order to reflect the tensile strength of the structural loess reasonably, firstly, the strength of soil is re-determined by introducing the joint strength criterion into the Duncan-Chang nonlinear constitutive model, and the failure stress ratio based on the joint strength theory of structural loess is corrected. Then, the tangent deformational modulus is re-determined by the modified failure stress ratio. Finally, the tangent Poisson's ratio is modified by the modified tangent deformational modulus, and the Duncan-Chang nonlinear constitutive model based on the joint strength theory is established, which provides a new method for reasonable consideration of the tensile strength characteristics of structural loess in the study on the stability of structural loess slopes.