Abstract: In light of the problem that the related triaxial stress seepage experiment devices lack of high pressure water and negative pressure loading function at present, the gas seepage law of coal samples cannot be studied under both of these cases. A kind of new triaxial stress seepage experiment device has been developed, of which the export negative pressure of coal sample itself is adjustable and the high pressure water can be loaded to the coal sample. The device is mainly composed of five parts including triaxial stress loading system, gas seepage system, hydraulic fracturing control system, gas flow test system, sensing and control system, all sorts of uniaxial and triaxial seepage experiments can be carried out in the case that samples are loaded by high pressure water or the negative pressure. Studies have shown that the device can simulate the gas migration law about coal body when the pressure of extraction drill hole is negative and can investigate the hydraulic fracturing effect of coal, complete the research about gas seepage law of coal sample under negative pressure condition, at the same time accomplish the inspection about the anti-reflection effect of coal body after hydraulic fracturing measures implemented in the laboratory.

Key words: seepage experiment device, permeability, triaxial stress, negative pressure drainage, hydrofracture