Abstract: Fractured rock mass under loading and unloading environment is ubiquitous with the influence of natural geological and artificial disturbance; the fracture surface geometry and the influence of unloading environment on fracture seepage characteristics can not be ignored in actual engineering. Using the methods of combining experimental and numerical simulation, to do the seepage flow experimental of fractured core with different roughnesses under loading and unloading, the thermo-hydro-mechanic coupling seepage flow system are used, to import the three dimensional morphology of fracture surface obtained by laser scanning into ABAQUS, the self-developed program is introduced. Both experimental and numerical simulations show that: The width and permeability of rough fracture decreases with the increase of load. With the increasing of load, the contact stiffness of fracture increases and the sensitivity of width and permeability decrease. The plastic deformation caused by points contact can not be recovered, The increasing amplitude of width and permeability of fracture decrease in stage of unloading, and less than that in loading stage under same conditions. Permeability, width and roughness of fracture were positively correlated. The greater the contact stress distribution is, the greater the roughness is. The field of flow in the crack is flow around islands, the greater the roughness, the phenomenon of flow around islands more obvious.

Key words: fracture, roughness, permeability, loading-unloading