基于幂函数关系的黏土非线性本构模型

结合软黏土双曲线模型和指数模型的切线模量公式,引入一个新参数——切线模量指数θ,提出改进的切线模量公式,进而推导出基于幂函数关系的软黏土非线性本构模型.该模型包含可由常规三轴试验确定的6个参数,数学关系简单且能克服传统模型的数学缺陷.通过讨论试验数据,表明切线模量指数θ与土体本身的力学性质、外界条件等因素有关,而与围压无关,进一步验证新模型中3个特征量的独立性.最后通过模拟两组他人的黏土三轴试验数据,证明新模型的模拟效果优于传统的双曲线模型与指数模型.

Nonlinear constitutive model of clay based on power function

A new parameter-tangential modulus index θ was introduced based on the tangential modulus of hyperbolic model and exponential model of soft clay and an improved tangential modulus formula was presented,so that a nonlinear constitutive model was derived on the basis of power function.Six parameters were included in this model,which could be determined by conventional triaxial test.With this mathematically simple model,the mathematic defects in the traditional models could be eliminated.By means of analysis of the test data,it was shown that the tangential modulus index θ was related to the mechanical properties of the soil itself and external condition,but not the confining pressure,verifying further the independence of the three characteristic quantities in the new model.By means of simulation of the new model with two sets of triaxial tests on clay soil offered by other authors,its was proved that the simulation result of new model was superior to that of hyperbolic model and exponential model.