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Abstract Research on rock materials during saturation process for the change regularities of velocity and electrical resistivity and the interrelation between them is significant in practical engineering，such as the judgment of rock physical properties，the comprehensive analysis and interpretation of geophysical data and so on. However，mineral composition，existing fissures and other factors of the rock sample often affect the experimental results. In order to prevent these influences，cement mortar is used to make 30 rock-like samples with different porosity. The changes of velocity and electrical resistivity for different samples were tested to reveal the change regularities of velocity and electrical resistivity with saturation and porosity. The theoretical formula among wave velocity，saturation，porosity is obtained by applying Gassmann equation based on the Wood theoretical assumption，but compared with the test results，it cannot describe the characteristic of wave velocity rapidly rising after the saturation reaches threshold value. A reasonable assumption considering the gravity effect to the distribution of pore water in the sample is made，the formula among wave velocity，saturation，porosity in the saturation process is modified，and it is nearly in accordance with the change characteristics of experiment data. Meanwhile Archie formula of unsaturated rock resistivity model is well used to fit the change rule of resistivity varying with saturation and porosity. On this basis，according to the problem that the past relationship between wave velocity and resistivity only consider porosity，the influence of porosity and saturated state is taken into account，and the relationship between wave velocity and resistivity is founded using porosity and saturated state as a bridge. It can provide a better fit to the real data，and the rationality is validated through experimentation with the protolith of limestone.
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2015, Vol. 34 
