This paper presents a new three-dimensional thermo-mechanical (TM) coupling approach for thermal fracturing of rocks in the finite–discrete element method (FDEM). The linear thermal expansion formula is implemented in the context of FDEM according to the concept of the multiplicative split of the deformation gradient. The presented TM formulation is derived in the geo-mechanical solver, enabling thermal expansion and thermally induced fracturing. This TM approach is validated against analytical solutions of the Cauchy stress, thermal expansion and stress distribution. Additionally, the thermal load on the previously validated configurations is increased and the resulting fracture initiation and propagation are observed. Finally, simulation results of the cracking of a reinforced concrete structure under thermal stress are compared to experimental results. Results are in excellent agreement.

本文提出了一种新的三维热机械耦合方法，以有限离散元方法（FDEM）对岩石进行热压裂。线性热膨胀公式是在FDEM中根据变形梯度的乘积分裂的概念实现的。提出的TM配方是在地质力学求解器中导出的，从而实现了热膨胀和热致裂化。该TM方法已针对柯西应力，热膨胀和应力分布的解析解进行了验证。另外，先前验证的构型上的热负荷增加，并且观察到了由此产生的裂缝萌生和扩展。最后，将钢筋混凝土结构在热应力作用下开裂的模拟结果与实验结果进行了比较。结果非常吻合。