Abstract: Based on the principle of in-situ transient pulse technique and its solving method, the small size in-situ transient pulse permeability measurement system, including data acquisition control system, pulse applying system, and permeability measuring system, has been developed successfully. Due to its simple configuration and small size, it is easy to control and use to measure the permeability of low-permeable in-situ confining rocks rapidly, which are often studied in geological disposal of radioactive waste，underground gas and oil storage tanks and construction of deep cavern groups, etc. Moreover, other kinds of rock mass within narrow surrounding spaces or serious disturbance requirements also can be measured. The small size in-situ transient pulse permeability measurement experiments have been introduced in this paper by using this system, of which the applicability, stability and accuracy have been proved.

Key words: in-situ permeability measurement system, small size, transient pulse technique