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由于地下水位的升降等原因,岩体经常处于干湿交替状态,这对岩体工程的长期稳定性不利。以红砂岩为研究对象,进行了干燥-饱水干湿交替作用后的常规单轴和三轴压缩试验研究,获得了砂岩应力-应变曲线,分析了其变形破坏特征。相对于没有经过干湿交替作用的干燥试件,经过不同次数的干燥-饱水交替作用后,砂岩的弹性模量、单轴和三轴抗压强度、黏聚力、内摩擦角等都有不同程度的降低。各力学指标的总体变化趋势是在第1次饱水之后均有较大幅度的下降,此后,随着干湿交替作用次数增加其降低的幅度逐渐减小,干湿交替作用使岩石的延性增强。在围压作用下,砂岩的峰值强度均随着围压的增大而增大,干燥试件强度的围压效应要比多次干湿交替作用后的试件显著。
Due to the rise and fall of groundwater level and other reasons, rock mass is often in alternate wet and dry conditions, which is not conducive to the long-term stability of rock mass engineering. Taking the red sandstone as the research object, the uniaxial and triaxial compression tests of the dry-saturated wet-dry alternation were carried out. The stress-strain curve of the sandstone was obtained and its deformation and failure characteristics were analyzed. Compared with the dry specimen without alternating wetting and drying, the elastic modulus, uniaxial and triaxial compressive strength, cohesion and internal friction angle of sandstone after the different times of dry-saturated water alternation Different degrees of reduction. The overall trend of each mechanical index after the first full of water have a more substantial decline, then, with the wet and dry alternate role of the number of its decrease decreases gradually, alternating wet and dry so that the ductility of the rock enhanced . Under the confining pressure, the peak intensity of sandstone increases with the increase of confining pressure, and the confining pressure effect of dry specimen strength is more significant than that of alternate wetting and drying specimens.