In this study, numerical simulations of the behaviour of large-size sandstone specimens exposed to wood crib fires were conducted. The developed numerical model, which innovatively considers the reversible quartz expansion behaviour during heating–cooling cycles, can replicate the temperature distributions, cracking behaviours, and strength variations of sandstone samples under various thermal loads (e.g., fires). Results show that the cracking mechanisms during heating and cooling are different, and the spalling is due to their combining effects. During the heating process, tensile stresses are induced mainly inside the sample due to significant expansions of the outer layer. The induced tensile microcracks beneath the surface will be furtherly extended and widened due to the re-distributed local stresses caused by local failures. After the fire, significant tensile stresses appear in the outer part of the sample due to the increased thermal gradients (i.e., volumetric expansions) of the inner part, leading to crack widening on the surface. These widened cracks will coalesce with the heating-induced cracks in the earlier time and boost the fracturing and spalling behaviour until the temperature across the sample reaches an equilibrium state. The findings are essential for understanding the failure mechanism of sandstone during real fire development. The good agreements between lab tests and numerical simulation also reveal the feasibility of using numerical models to predict the fire-induced damage in sandstone elements in architecture.

在这项研究中，进行了模拟大尺寸砂岩标本暴露于木婴儿床火灾的行为的数值模拟。所开发的数值模型创新地考虑了加热-冷却循环期间可逆的石英膨胀行为，可以复制砂岩样品在各种热负荷（例如火灾）下的温度分布，开裂行为和强度变化。结果表明，加热和冷却过程中的开裂机理是不同的，剥落是由于它们的结合作用所致。在加热过程中，由于外层的明显膨胀，拉伸应力主要在样品内部产生。由于局部失效引起的局部应力的重新分布，表面下的拉伸微裂纹将进一步扩展和加宽。大火过后 由于内部的热梯度增加（即体积膨胀），样品的外部会出现明显的拉应力，从而导致表面裂纹扩展。这些加宽的裂纹将在更早的时间内与加热引起的裂纹融合，并增强断裂和剥落行为，直到样品上的温度达到平衡状态为止。这些发现对于理解真实火灾发展过程中砂岩的破坏机理至关重要。实验室测试与数值模拟之间的良好一致性也揭示了使用数值模型预测建筑中砂岩元素火灾引起的破坏的可行性。导致表面裂纹扩展。这些加宽的裂纹将在更早的时间内与加热引起的裂纹融合，并增强断裂和剥落行为，直到样品上的温度达到平衡状态为止。这些发现对于理解真实火灾发展过程中砂岩的破坏机理至关重要。实验室测试与数值模拟之间的良好一致性也揭示了使用数值模型预测建筑中砂岩元素火灾引起的破坏的可行性。导致表面裂纹扩展。这些加宽的裂纹将在更早的时间内与加热引起的裂纹融合，并增强断裂和剥落行为，直到样品上的温度达到平衡状态为止。这些发现对于理解真实火灾发展过程中砂岩的破坏机理至关重要。实验室测试与数值模拟之间的良好一致性也揭示了使用数值模型预测建筑中砂岩元素火灾引起的破坏的可行性。这些发现对于理解真实火灾发展过程中的砂岩破坏机理至关重要。实验室测试与数值模拟之间的良好一致性也揭示了使用数值模型预测建筑中砂岩元素火灾引起的破坏的可行性。这些发现对于理解真实火灾发展过程中砂岩的破坏机理至关重要。实验室测试与数值模拟之间的良好一致性也揭示了使用数值模型预测建筑中砂岩元素火灾引起的破坏的可行性。