摘要In order to study how the splitting tensile strength of layered rock is influenced by varied moisture contents，samples of layered sandstone with five different moisture contents were used in the splitting tensile strength test along the weak stratification plane. The tensile strength of layered sandstone decreases fast initially and slowly then as the moisture content increases. When the saturation degree is lower than 80%，the tensile strength is reduced significantly. With the increasing of saturation，the parameters of height and texture of the fractured rock surface increase fast initially and slow then. Besides, there is a good linear correlation between the tensile strength of rock and the microstructure parameter of splitting surface. The total energy absorbed by the sample and the elastic strain energy in the loading process decrease gradually as the moisture content increases. The ratio of elastic strain energy to total energy decreases while the dissipated energy ratio goes up. The weak bedding plane is not only the weak surface of layered rock structure，but also the main absorption space and migration channels for moisture. The mechanical property of weak bedding surface and the distribution of pore water vary with the increasing of moisture contents and the crack propagation is changed in the in-situ loading process，which directly influences the proportion of the elastic strain energy and dissipation during the loading process. In conclusion，the influence of water content on the tensile strength of rock is a progressive process of microscopic structure changing to the macroscopic degradation of mechanical properties.
Abstract：In order to study how the splitting tensile strength of layered rock is influenced by varied moisture contents，samples of layered sandstone with five different moisture contents were used in the splitting tensile strength test along the weak stratification plane. The tensile strength of layered sandstone decreases fast initially and slowly then as the moisture content increases. When the saturation degree is lower than 80%，the tensile strength is reduced significantly. With the increasing of saturation，the parameters of height and texture of the fractured rock surface increase fast initially and slow then. Besides, there is a good linear correlation between the tensile strength of rock and the microstructure parameter of splitting surface. The total energy absorbed by the sample and the elastic strain energy in the loading process decrease gradually as the moisture content increases. The ratio of elastic strain energy to total energy decreases while the dissipated energy ratio goes up. The weak bedding plane is not only the weak surface of layered rock structure，but also the main absorption space and migration channels for moisture. The mechanical property of weak bedding surface and the distribution of pore water vary with the increasing of moisture contents and the crack propagation is changed in the in-situ loading process，which directly influences the proportion of the elastic strain energy and dissipation during the loading process. In conclusion，the influence of water content on the tensile strength of rock is a progressive process of microscopic structure changing to the macroscopic degradation of mechanical properties.
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2017, Vol. 36 
