高温下岩石损伤本构模型及其验证

为完善高温条件下的岩石损伤本构模型及参数确定方法，基于有效应力理论，引入Weibull分布函数，在微元体强度服从Hoek-brown准则的条件下，考虑残存强度影响，对损伤变量修正，引入损伤修正系数，建立了能够反映高温作用下的岩石损伤特征统计本构模型。考虑岩石损伤过程中的损伤阈值因素，对本构模型采用分段函数的形式。通过试验，获取常规力学参数，依据本构模型参数求解过程，确定本构模型参数值，并拟合模型参数值与温度之间的关系。对模型理论曲线进行验证。结果表明：提出的高温岩石统计损伤本构模型理论曲线与试验曲线具有较好地相似性，更加贴近试验曲线，体现了本构模型的合理性。同时模型理论曲线与岩石三轴试验曲线具有较高的吻合度，说明本构模型能够反映出岩石的全应力? 应变曲线特征，能够体现出模型的适用性。模型为岩石强度的估算和岩石热损伤软化问题提供了参考。

Damage constitutive model of rock under high temperature and its verification

In order to improve the rock damage constitutive model and parameter determination method under high temperature, based on the effective stress theory, the Weibull distribution function is introduced. Under the condition that the micro-element strength obeys the Hoek-brown criterion, the influence of residual strength is considered, the damage variables are modified, the damage correction coefficient is introduced, and a statistical constitutive model that can reflect the damage characteristics of rocks under high-temperature action is established. Considering the damage threshold factor in the rock damage process, the present constitutive model takes the form of a piecewise function. The conventional mechanical parameters are obtained by testing. Based on the process of solving the parameters of the constitutive model, the values of the constitutive model parameters are determined and the relationship between the values of the model parameters and the temperature is fitted. Finally, the theoretical curve of the model is verified. The results show that the theoretical curve of the proposed statistical damage constitutive model for high-temperature rocks has a good similarity with the test curve, and it is closer to the test curve and reflects the reasonableness of the constitutive model. At the same time, the theoretical curve of the model has a high degree of coincidence with the triaxial test curve, which indicates that the constitutive model can reflect the characteristics of the full stress-strain curve of the rock and can reflect the applicability of the model. The model provides a reference for rock strength estimation and rock thermal damage softening.