Abstract: When doing permeability test by using pressure pulse test method, the straddle packer system is adopted to isolate the test interval with the other parts of borehole; and then increase the pressure of test interval by high-pressure pump rapidly. The system is then shut-in and the pressure decay curve is recorded. By fitting the recorded data with the type curve, the permeability of test rock mass could be determined. Permeability test results of three intervals of one borehole in use of pressure pulse test method at granite mass in Gansu Province are presented. The test results are compared with Lugeon test results in the same borehole and statistical analysis of permeability test results in other areas. As one method of rock mass permeability test, pressure pulse test has superiority to other methods for its convenience and shorter time consuming, and is suitable for low permeability rock mass test especially.

Key words: pressure pulse test, permeability, granite mass