黏土非线性模型的改进切线模量

Improved tangent modulus of nonlinear soil model

切线模量描述是土体非线性模型中的一个基本问题。首先,引入“半值强度指数”概念建立了土体应力应变曲线的数学特征方程,分析了双曲线应力应变模型的数学缺陷。接着,根据试验数据分析提出了土体应力应变曲线的控制微分方程,建立了土体应力应变曲线的3参数新模型,新模型克服了双曲线模型的缺陷;证明了双曲线模型是该新模型的特例。最后,在3参数新模型的基础上,改进了土体的切线模量表达,给出了参数确定方法,并对三轴试验结果进行了模拟。

Tangent modulus was essential to nonlinear soil model, and it was necessary to understand it properly during numerical simulation. First, a new concept namely half strength index was introduced to build the mathematic properties equations of stress-strain relationship, then the deficiency of hyperbolic expression of the relationship was indicated in terms of it. Second, according to laboratory test data, differential control equation of soil stress-strain relationship was presented and a new 3-parameter stress-strain expression was established. It was shown that the hyperbolic expression was the simplified type of the 3-parameter expression. Third, an improved tangent modulus of soil was obtained based on the new stress-strain expression, and methods to determine its parameters were discussed. Finally, simulation of triaxial test data using the improved tangent modulus was conducted.