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Abstract In the correlation research of rock saturation degree，longitudinal wave velocity and strength，the influences of saturation process and air-drying process on strength and longitudinal wave velocity are lack of comprehensive consideration；however，the study of these problems is of great significance for ultrasonic technology in the testing of rock physico-mechanical parameters. Based on these，typical layered sandstones in the Three Gorges reservoir area were selected，vertical-bedding samples and parallel-bedding samples were prepared to conduct saturation and air-drying experiment. The experimental results show that：(1) The relationship between longitudinal wave velocity and saturation degree is obviously nonlinear and nonmonotonic；the longitudinal wave velocity of water-bearing rock is not only related to saturation degree，but also associated with saturation process and air-drying process. (2) The anisotropy of sandstone is obvious；the longitudinal wave velocity change range of vertical-bedding rock is significantly greater than that of the parallel-bedding rock in the process of saturation and air-drying；and the anisotropic characteristics of the sandstone increase slightly under saturated state. (3) In the process of saturation and air-drying，the changing laws of compressive strength and longitudinal wave velocity are inconsistent. The adsorbed water which is on the surface of mineral particles and pore wall has a great influence on elastic modulus and strength；however，the influence of pore saturation degree on longitudinal wave velocity is more apparent. These research results have important reference value for the strength and longitudinal wave velocity tests of water-bearing rock；what?s more，the relevant test methods can provide reference for similar test.
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Received: 26 January 2013
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2013, Vol. 32 
