针对深部开采和核废料处置等重大工程的需求,对温度.应力共同作用下岩石的力学行为研究具有十分重要的意义。该文通过试验研究了不同温度影响下小尺寸双边缺口砂岩试件的断裂特性,发现温度与断裂韧性存在非线性指数关系,具体表现为温度从25℃升到150℃时,断裂韧性随温度指数升高;而温度由150℃升高到300℃,断裂韧性随温度指数下降,150℃是断裂韧性变化的临界温度。研究认为小尺寸、粘土矿物及热开裂是造成断裂韧性变化的主要原因,并解释了与多数宏观试验结果不同的可能原因。
It is important to study the mechanical characteristics of rocks to meet the increasing demands of deep mining and nuclear waste disposal. This paper mainly studies the temperature effects on fracture toughness of sandstone sample with double notches through meso-experiments. The experiments indicate that the fracture toughness increases exponentially with the temperature increment from 25℃ to 150℃ while decreases exponentially with the temperature increment from 150℃ to 300℃, and therefore 150℃ is the critical temperature. This result differs from most macroscopic experimental results. The possible reasons, such as meso-scale, clay mineral and thermal cracking, are analyzed in detail.