土工合成材料界面应变软化特性的一种本构新模型

在土工合成材料工程的数值研究中,根据土工合成材料界面的力学特性,构建合理有效的本构模型是提高数值计算可靠性的关键.针对部分土工合成材料界面存在的应变软化特性,提出了一种新的本构模型.以剪应力峰值为分界点,将剪应力剪切位移曲线前后两部分分别进行模拟.剪应力峰值前,采用Clough和Duncan双曲线模型进行模拟;剪应力峰值后的应变软化阶段,以剪应力峰值为原点,用另外一条倒置的双曲线进行模拟.通过系统的公式推导描述了模型的构建过程,给出了应变软化阶段界面剪切刚度计算表达式.通过对界面直剪试验结果的模拟初步验证了模型的拟合能力.

A new constitutive model for strain softening behavior in geosynthetic interface

In order to enhance the reliability of numerical calculation, it is the key to establish the effective and reliable constitutive model according to the mechanical properties of geosynthetic interface in the numerical study of geosynthetic engineering. Aiming at the strain softening behavior of partial geosynthetic interface, a new constitutive model was proposed. Through taking the peak shear stress as the demarcation point, the former and later parts of shear stress displacement curve were simulated, respectively. Before the peak shear stress point, the curve was simulated with the Clough and Duncan hyperbolic model. For the strain softening stage after the peak shear stress point, the peak shear stress was taken as the origin point, and the stress displacement curve was simulated with another inverted hyperbolic curve. The establishment process of new constitutive model was described by the systemic formulas derivation, and the expression of interface shear stiffness in the strain softening stage was given. Furthermore, the fitting ability of the model is preliminarily approved with the simulation of direct shear test of interface.