Abstract: 30 joint-slices with 10 grades of roughness（JRC=1~20）and 3 kinds of thickness (1.5, 3.0, 5.0 mm) are produced by using 3D printing technology, and then poured into rock-like specimens containing consecutive and filling fracture by moulds. Then the seepage tests are carried out on these specimens with different roughness levels and gap-widths under different confining pressures. The test results show that the permeability of consecutive and filling fracture with different roughness levels and gap-widths decreases with the increase of confining pressure. Moreover, the decrease rate of permeability in the initial stage of confining pressure loading is obviously higher than that in the middle and late periods, and the maximum permeability drop is 78%. In the initial stage of confining pressure loading, when the gap-width is small, the roughness has a great influence on the seepage characteristic of consecutive and filling fracture. While, as the gap-width and confining pressure increase, the effect of the roughness on the fracture permeability rapidly decreases. For all consecutive and filling fracture with 10 grades of roughness, the permeability increases with the increase of the gap-width in the initial and late stages of confining pressure loading. When the confining pressure is small, the larger the roughness is, the greater difference the permeability of consecutive and filling fracture at different gap-widths has. However, with the increase of confining pressure, the difference is gradually reduced. The confining pressure have a dominant influence on the permeability of consecutive and filling fracture, and their relationship can be described by a power function.

Key words: consecutive and filling fracture, loading of confining pressure, joint roughness coefficient(JRC), gap-width, seepage characteristic