温度冲击下煤的双胡克体-统计损伤本构模型研究

A double hook-statistical damage constitutive model of coal under temperature impact

为研究温度冲击作用下煤体破坏特性,利用SLX-80高低温处理系统对取自赵固二矿的煤样进行了不同温度冲击,用RLW-500G煤岩三轴压缩试验系统对不同温度冲击的煤进行了三轴压缩试验,分析了煤在温度冲击条件下的力学特征。实验结果表明随温度梯度的增大,煤的弹性模量和三轴抗压强度近似呈线性降低。基于煤岩强度服从Weibull分布的假设和煤岩强度应变理论,利用损伤力学理论,引入热损伤变量,建立了温度冲击下煤的双胡克体-统计损伤本构模型,给出了模型参数的详细计算方法,结合实验数据对该模型进行了理论验证。分析表明,双胡克体-统计损伤本构模型结构简单,引入参数少,物理意义清晰,且考虑了温度效应,能够有效地描述温度冲击下煤体破坏全过程的力学性质。

In order to study the failure characteristics of coal under temperature impact,different temperature impacts have been carried out on coal samples from Zhaogu No.2 Mine through SLX-80 high-low temperature treatment system,and triaxial compression tests have been carried out on the coal with temperature impacts through RLW-500 G coal rock triaxial compression test system.And then the mechanical properties of coal under temperature impact conditions have been analyzed.The experimental results have indicated that the elastic modulus and triaxial compressive strength of coal decrease linearly with the increase of temperature gradient.Besides,the theory of damage mechanics is used to introduce the thermal damage variable and a double hook-statistical damage constitutive model of coal under temperature impact is built based on the assumption of coal strength subject to Weibull distribution and the theory of strength and strain of coal rock.The detailed calculation method of the model parameters is proposed,and the correctness of the model is verified through the testing data.The research results have shown that the double hook-statistical damage constitutive model can effectively describe the mechanical properties of the whole process of coal damage under temperature impact,with its advantages including simple construction,few parameters,clear physics meaning,and temperature effect taken into consideration.