Enhancing our understanding of the damage evolution in pre-heated rock is essential for safer design practices. Accordingly, a mechanical damage variable that accurately depicts the initial damage recovery process was proposed. Subsequently, a damage constitutive model is developed based on the generalized equivalent strain principle, enabling the identification of the initial nonlinear characteristics exhibited in the stress-strain curve. By integrating the above constitutive model with a statistical damage model that considers the residual strength based on the Weibull distribution, a comprehensive piecewise damage constitutive model specifically designed for pre-heated rocks was derived. The model consists of eight parameters, which can be directly determined through experimental results or readily obtained by fitting of the stress-strain data. A comparison of experimental data from multiple pre-heated rock types subjected to uniaxial compression is performed to validate the proposed model, revealing a strong agreement between the theoretical and experimental results. The comparison results demonstrate that the proposed model effectively captures the nonlinearity of the stress-strain curve throughout various stages, including the initial compaction, linear elastic, and strain-hardening stages before reaching the peak stress, as well as the subsequent strain-softening and residual stages. Furthermore, the proposed damage constitutive model elucidates the influence of temperature on crucial factors such as the elastic modulus, peak stress, residual strength, and stress-strain curve of pre-heated rocks, thereby enhancing its applicability in the design of deep underground rock projects.

中文翻译：

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考虑初始压实效应和残余强度的改进的预热岩石单轴压缩损伤本构模型


增强我们对预热岩石损伤演变的理解对于更安全的设计实践至关重要。因此，提出了准确描述初始损伤恢复过程的机械损伤变量。随后，基于广义等效应变原理开发了损伤本构模型，能够识别应力-应变曲线中表现出的初始非线性特征。将上述本构模型与基于威布尔分布的考虑残余强度的统计损伤模型相结合，导出了专门针对预热岩石设计的综合分段损伤本构模型。该模型由八个参数组成，这些参数可以通过实验结果直接确定，也可以通过应力应变数据拟合轻松获得。对多种预热岩石类型进行单轴压缩的实验数据进行比较，以验证所提出的模型，揭示了理论与实验结果之间的高度一致性。比较结果表明，该模型有效地捕捉了应力-应变曲线在各个阶段的非线性，包括达到峰值应力之前的初始压实、线弹性和应变硬化阶段，以及随后的应变软化和应变硬化阶段。剩余阶段。此外，所提出的损伤本构模型阐明了温度对预热岩石的弹性模量、峰值应力、残余强度和应力应变曲线等关键因素的影响，从而增强了其在深层地下岩石工程设计中的适用性。