Fracture toughness is an important parameter in determining the fracture mechanism of rocks, concretes and other composites, and it is used in performing design and stability analyses. In this study, the aim was to determine the effects of different environmental conditions (dry, saturated, freezing, thermal shock and thermal aging) on fracture toughness and fracture energy values of rocks from three different origins: gabbro, recrystallized limestone and limestone. In the first stage, the physical, chemical, mechanical, mineralogical and petrographic properties of rocks were determined. The material properties of rocks were revealed by physico-mechanical tests, XRD, XRF and petrographic analysis. In the second stage, the rocks were aged by exposing them to pre-determined environmental conditions for a certain period of time and then, semi-circular bending strength tests were applied to the aged rocks. SEM images were taken to determine the effects of different environmental conditions on surface cracks. According to the experimental results, thermal shock, thermal ageing and water saturation conditions led to decreasing fracture toughness, while freezing conditions led to increasing fracture toughness. It was determined that thermal shock was the environmental condition that caused the most weakening. In freezing conditions, it was observed that physico-mechanical properties and fracture toughness values of rocks increased. It was seen that the fracture toughness values of the monomineralic structured samples were more affected by the environmental conditions than the multimineralic rocks.

断裂韧性是确定岩石、混凝土和其他复合材料断裂机制的重要参数，用于进行设计和稳定性分析。本研究的目的是确定不同环境条件（干燥、饱和、冷冻、热冲击和热老化）对来自三个不同来源的岩石断裂韧性和断裂能值的影响：辉长岩、重结晶石灰岩和石灰岩。在第一阶段，确定岩石的物理、化学、机械、矿物学和岩相性质。通过物理力学测试、X射线衍射、X射线荧光和岩相分析揭示了岩石的材料特性。第二阶段，将岩石暴露在预定的环境条件下一定时间，使其老化，然后对老化的岩石进行半圆弯曲强度测试。拍摄 SEM 图像以确定不同环境条件对表面裂纹的影响。实验结果表明，热冲击、热老化和水饱和条件导致断裂韧性降低，而冷冻条件导致断裂韧性增加。经确定，热冲击是造成最弱化的环境条件。在冻结条件下，观察到岩石的物理机械特性和断裂韧性值增加。可以看出，单矿物结构样品的断裂韧性值比多矿物岩石更受环境条件的影响。