A thermo-mechanical damage constitutive model for deep rock considering brittleness-ductility transition characteristics  

考虑脆延转化特性的深部岩石热-力损伤的本构模型

作　　者：FENG Chen-chen WANG Zhi-liang WANG Jian-guo LU Zhi-tang LI Song-yu 封陈晨;王志亮;王建国;卢志堂;李松玉(School of Civil and Hydraulic Engineering,Hefei University of Technology,Hefei 230009,China;School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou 221116,China;School of Resources and Environmental Engineering,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]School of Civil and Hydraulic Engineering,Hefei University of Technology,Hefei 230009,China [2]School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou 221116,China [3]School of Resources and Environmental Engineering,Hefei University of Technology,Hefei 230009,China

出　　处：《Journal of Central South University》2024年第7期2379-2392,共14页中南大学学报（英文版）

基　　金：Project(11272119)supported by the National Natural Science Foundation of China。

摘　　要：This paper developed a statistical damage constitutive model for deep rock by considering the effects of external load and thermal treatment temperature based on the distortion energy.The model parameters were determined through the extremum features of stress−strain curve.Subsequently,the model predictions were compared with experimental results of marble samples.It is found that when the treatment temperature rises,the coupling damage evolution curve shows an S-shape and the slope of ascending branch gradually decreases during the coupling damage evolution process.At a constant temperature,confining pressure can suppress the expansion of micro-fractures.As the confining pressure increases the rock exhibits ductility characteristics,and the shape of coupling damage curve changes from an S-shape into a quasi-parabolic shape.This model can well characterize the influence of high temperature on the mechanical properties of deep rock and its brittleness-ductility transition characteristics under confining pressure.Also,it is suitable for sandstone and granite,especially in predicting the pre-peak stage and peak stress of stress−strain curve under the coupling action of confining pressure and high temperature.The relevant results can provide a reference for further research on the constitutive relationship of rock-like materials and their engineering applications.为了研究深部岩石高温条件下的损伤力学特性及构建考虑外载荷和温度影响的含损伤本构模型,本文先分析了岩石损伤和变形机理,借助材料力学畸变能理论和损伤力学理论,建立了常温下岩石损伤本构模型。接着,通过耦合荷载损伤变量和热损伤变量,推导出深部岩石的损伤演化方程,并构建了基于耦合损伤变量和裂纹起裂阈值的深部岩石热-力损伤本构模型。最后,根据应力-应变曲线的极值特征确定模型参数,将模型预测结果与大理岩、砂岩和花岗岩等的试验结果进行比较。结果表明本文所建模型与试验数据吻合较好,且在三轴压缩条件下也有较强适用性,可反映温度对深部岩石力学性能的劣化特性及围压环境下的峰后脆延性转化特征。相关研究成果可为岩石脆性材料本构关系的进一步研究和工程应用提供参考。

关 键 词：deep rock crack initiation threshold thermo-mechanical coupling statistical damage model distortion energy theory 

分 类 号：TU45[建筑科学—岩土工程]