The failure of layered rock after high temperature exposure is a major concern in deep underground engineering projects. This paper proposes an improved Nishihara creep constitutive model that considers damage factors and the bedding angle, which overcomes the shortcomings of the deviation in the description of the conventional Nishihara model in the acceleration stage. The constitutive model is verified by the conventional triaxial creepiest. The theoretical curve has a high degree of fitting with the experimental curve. The experimental results show that a temperature of [Formula: see text] has an obvious influence on the steady creep rate and the creep strain of layered sandstone, and [Formula: see text] can be regarded as the temperature threshold for the long-term strength and change from anisotropic to isotropic of layered sandstone. The irreversible melting mixing phenomenon at the boundary of mineral particles with increasing temperature is the mechanism by which different treatment temperatures affect the anisotropy degree of layered rock.

中文翻译：

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考虑各向异性和损伤因素的层状岩石高温后蠕变本构模型研究


层状岩石在高温暴露后失效是深部地下工程工程中的主要问题。本文提出了一种改进的 Nishihara 蠕变本构模型，该模型考虑了损伤因子和层理角，克服了常规 Nishihara 模型在加速阶段描述偏差的缺点。本构模型通过常规的三轴蠕变最强验证。理论曲线与实验曲线拟合度高。试验结果表明，温度为[公式]对层状砂岩的稳态蠕变速率和蠕变应变有明显影响，[公式：见正文]可视为层状砂岩长期强度和由各向异性变为各向同性的温度阈值。矿物颗粒边界处随温度升高的不可逆熔融混合现象是不同处理温度影响层状岩石各向异性程度的机制。