砂岩与花岗岩在冻融循环和化学腐蚀下力学性能及断裂韧度变化的对比

为探究冻融循环-多种化学溶液溶蚀等因素耦合作用下岩石力学特性的变化规律,选取砂岩和花岗岩作为岩样开展了一系列岩石力学试验,借助智能显微镜观察比较了不同外部条件影响下岩石的表面微观结构,分析了岩石的溶液溶蚀机理和冻融损伤机理。试验结果表明岩石应力-应变关系、弹性模量、峰值应力、断裂韧度等力学特性受溶液溶质种类的影响较小,而受冻融循环温度影响显著,砂岩受冻融循环破坏程度大于花岗岩。两种岩石力学特性都随冻融循环温度的降低而减弱,I型断裂韧度与冻融循环温度之间呈二次函数关系。

Comparison of mechanical properties and fracture toughness changes of sandstone and granite under freeze-thaw cycle and chemical corrosion

A series of rock mechanics tests were carried out on sandstone and granite samples, to study the variation law of rock mechanical characteristics under the coupling effect of freeze-thaw cycling and multiple chemical solutions corrosion. The surface microstructures of rock under different external conditions were observed and compared via intelligent microscopy. The chemical corrosion and freeze-thaw damage mechanism were analyzed. The test results show that the mechanical properties of rock, such as stress-strain relationship, elastic modulus, peak stress and fracture toughness, are less affected by the type of chemical solutions, and are significantly affected by freeze-thaw cycling temperature. The damage degree of sandstone under freeze-thaw cycling is greater than that of granite. The mechanical properties of both rocks decrease with the decrease of freeze-thaw cycling temperature. The relationship between fracture toughness type I and freeze-thaw cycling temperature is quadratic function.