To assess the influence of thermal stress on fracture deformation, a composite element algorithm of thermo‐mechanical coupling for fractured rock mass is developed based on the composite element method (CEM). This study aims to investigate coupled processes associated with the (i) effect of temperature on mechanical deformation and (ii) effect of fracture aperture on heat transfer. The composite element contains fracture segments exhibiting arbitrary shapes with variables that can be interpolated from their mapped nodal variables; the mapped variables can be determined using the governing equations derived from the variational principle or virtual work principle. The proposed coupling algorithm can simulate the discontinuity of fractures, with consideration of the heat transfer of rock blocks and fractures, together with heat exchange among fractures and the adjacent rock mass. A computational mesh is generated without restrictions by explicitly embedding the fractures into the mapped composite elements, substantially simplifying the pre‐process work. Analytic solutions to the transient temperature problem are examined to verify the proposed CEM algorithm. Two three‐dimensional numerical models are developed to perform thermo‐mechanical coupling analyses. These analyses are used to prove the advantage of the mesh handler and the reliability of the proposed algorithm. During coupling with the CEM model, the computational mesh requires no modification regardless of changes in fracture aperture. Results indicate that an increase in temperature leads to rock expansion, causing fracture deformation, which affects the general temperature of the fractured rock mass.

中文翻译：

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复合单元法的裂隙岩体热力耦合算法

为了评估热应力对裂缝变形的影响，基于复合单元法（CEM），开发了裂隙岩体热力耦合的复合单元算法。这项研究旨在研究与（i）温度对机械变形的影响和（ii）裂隙孔径对热传递的影响有关的耦合过程。复合单元包含显示为任意形状的断裂段，这些断裂段的变量可以从其映射的节点变量中进行插值。可以使用从变分原理或虚拟功原理导出的控制方程式确定映射变量。结合岩石块和裂缝的传热，提出的耦合算法可以模拟裂缝的不连续性，以及裂缝和邻近岩体之间的热交换。通过将裂缝明确嵌入到映射的复合元素中，可以不受限制地生成计算网格，从而大大简化了预处理工作。研究了瞬态温度问题的解析解，以验证所提出的CEM算法。开发了两个三维数值模型来执行热机械耦合分析。这些分析被用来证明网格处理器的优点和所提出算法的可靠性。在与CEM模型耦合期间，无论断裂孔径如何变化，计算网格都不需要修改。结果表明，温度升高会导致岩石膨胀，导致裂缝变形，