冻土–复合土工布界面复合幂–指数本构模型研究

Composite Power-Exponential Constitutive Modelling on Frozen Soil-Composite Geotextile Interface

摘要: 土工合成材料广泛应用于各种工程中，由于土体与土工合成材料的物理力学特性差异明显，且土体易受水热条件影响，不同条件下界面的剪切力学特性存在明显的差异，界面的应力应变曲线也存在较大的形态差异。为准确描述冻土–复合土工布界面剪切特性，基于在不同水热循环工况下进行直剪试验得到的试验数据，提出了一种改进的复合幂–指数界面本构模型，并对得到的模型参数进行了分析和讨论。结果表明该模型能准确地反映不同类型的软化型和硬化型曲线，模型中不同参数有其对应的明确物理意义。针对不同复杂工况条件下的应力应变关系进行有效的拟合，并结合具体试验工况给出典型的有代表性的拟合函数关系式，对冻土区基础工程建设具有指导和参考意义。

Abstract: Geosynthetics are widely used in a variety of projects, due to the obvious differences in the physical and mechanical properties of the soil and geosynthetics, and the soil is susceptible to hydrothermal conditions, there are obvious differences in the shear mechanical properties of the interface under different conditions, and there are also large differences in the shape of the stress-strain curve at the interface. To accurately describe the shear characteristics of the frozen soil-composite geotextile interface, an improved composite power-exponential interfacial constitutive model is proposed based on the test data obtained from direct shear tests carried out under different hydrothermal cycling conditions, and the obtained model parameters are analyzed and discussed. The results show that the model can accurately reflect different types of softening and hardening curves, and the different parameters in the model have their corresponding clear physical meanings. The stress-strain relationship under different complex working conditions is fitted effectively, and a typical and representative fitted functional relationship is given in combination with specific test conditions, which is of guiding and reference significance for the construction of infrastructure projects in frozen soil areas.