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Abstract By using 20 MN servo-controlled triaxial rock testing machine with high temperature and high pressure，the real-time seepage laws of 4 pieces of intact granite samples under hydrostatic pressures of 25 and 75 MPa with thermal cracking action(TCA) are researched. It is the first real-time experimental study on seepage law of granite under high temperature with three-dimensional stress. This research results are listed as follows：(1) Under three-dimensional stress，there is thermal cracking phenomenon for all granite samples. Through the seepage law of intact granite rock sample，it is found that permeability shows of exponential growth function of temperature through the process of thermal cracking. (2) The permeability of granite sample has a slow growth through initial stage of thermal cracking action，a rapid growth through late stage of TCA and up to peak value of permeability in the final with increase of temperature. (3) The permeability and its rate of granite sample have a continuous growth through whole stage of TCA with increasing temperature. (4) The ratio of peak value of permeability to its initial value is up to 93 and permeability rate is up to 3.5×10—4 mD/℃. TCA has an important role in enhancing permeability of granite. Experimental data and conclusion have an important significance for construction of exploitation of hot dry rock，secondary oil exploitation and underground coal gasification.
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Received: 10 June 2009
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