The stability of rock mass after fire is a concern of many engineering projects. In this paper, the effects of open fire and different cooling methods on granites were investigated. The static Brazilian test, dynamic Brazilian test, and P-wave velocity test were carried out to evaluate the mechanical properties and damage evolution behavior. A high-speed camera is employed to monitor the failure process of rock. The microstructures of the treated granites were observed by scanning electron microscope (SEM). The results showed that the fire duration and cooling treatment have a significant effect on the P-wave velocity, static nominal tensile strength, and dynamic nominal tensile strength of granite. These characteristics decrease rapidly during 0 to 10 min, and slowly decrease after 20 min. Compared to the air-cooling treatment, the water-cooling treatment has greater damage to the heated granite. To better understand the results, the rapid heating process of open fire heating was simulated using Abaqus software. The results reveal that there is a thinner compressive stress zone at the bottom of the specimen, and there is a large zone in the middle of the sample with higher tensile stress. The crack extension would be expanded due to high tensile stress, leading to the reduction of the tensile strength of the rock. This paper aims to better predict the degree of damage of rock materials after actual fire, as well as preliminarily explore the effect of the fire exposure duration and fire extinguishing method on the tensile properties of rock.

火灾后岩体的稳定性是许多工程项目关注的问题。本文研究了明火和不同冷却方法对花岗岩的影响。进行了静态巴西试验、动态巴西试验和纵波速度试验，以评估力学性能和损伤演化行为。采用高速摄像机监测岩石的破坏过程。用扫描电子显微镜（SEM）观察处理后花岗岩的显微组织。结果表明，火持续时间和冷却处理对花岗岩的纵波速度、静态标称抗拉强度和动态标称抗拉强度有显着影响。这些特征在 0 到 10 分钟内迅速下降，并在 20 分钟后缓慢下降。与风冷处理相比，水冷处理对加热后的花岗岩破坏较大。为了更好地理解结果，使用 Abaqus 软件模拟了明火加热的快速加热过程。结果表明，试样底部有较薄的压应力区，而试样中间有较大的拉应力区。由于高拉应力，裂缝扩展会扩大，导致岩石的抗拉强度降低。本文旨在更好地预测实际火灾后岩石材料的破坏程度，并初步探讨火灾暴露时间和灭火方法对岩石拉伸性能的影响。使用Abaqus软件模拟明火加热的快速加热过程。结果表明，试样底部有较薄的压应力区，而试样中间有较大的拉应力区。由于高拉应力，裂缝扩展会扩大，导致岩石的抗拉强度降低。本文旨在更好地预测实际火灾后岩石材料的破坏程度，并初步探讨火灾暴露时间和灭火方法对岩石拉伸性能的影响。使用Abaqus软件模拟明火加热的快速加热过程。结果表明，试样底部有较薄的压应力区，而试样中间有较大的拉应力区。由于高拉应力，裂缝扩展会扩大，导致岩石的抗拉强度降低。本文旨在更好地预测实际火灾后岩石材料的破坏程度，并初步探讨火灾暴露时间和灭火方法对岩石拉伸性能的影响。由于高拉应力，裂缝扩展会扩大，导致岩石的抗拉强度降低。本文旨在更好地预测实际火灾后岩石材料的破坏程度，并初步探讨火灾暴露时间和灭火方法对岩石拉伸性能的影响。由于高拉应力，裂缝扩展会扩大，导致岩石的抗拉强度降低。本文旨在更好地预测实际火灾后岩石材料的破坏程度，并初步探讨火灾暴露时间和灭火方法对岩石拉伸性能的影响。