Abstract: The experimental study on the shear-seepage coupling characteristics and mechanism of filling granite joints
under the influence of seepage water pressure has important theoretical significance and engineering application value for the
prevention and control of slope instability disasters in metal mines under such geological environment conditions. Based on the
engineering geological characteristics of granite slope in a metal mine in Guizhou,the granite joint surface was obtained by
splitting test and the kaolin-filled granite-like joint samples were made by similar materials. The normal load boundary condition
was set and the normal stress was set to 2 MPa. Three kinds of seepage water pressure and five kinds of filling degree
schemes were designed to carry out joint shear-seepage coupling test. After the test,high-definition camera and three-dimensional
scanning were performed on the joint surface. The test results show that the shear stress-shear displacement curves of
joints have three types:"single-step type","double-step type" and "peak-step type". The normal displacement-shear displacement
curves are basically concave " shear contraction-dilatancy type" curves. The seepage flow-shear displacement curve has
two types:" fluctuation reduction type " and "overall stable type". The peak friction angle of the joint is mainly 29° to 48°,
and the peak dilatancy angle is mainly-8° to 8°. Both of them decrease with the increase of filling degree. Under the same filling
degree,the average seepage flow of joints increases approximately linearly with the increase of seepage pressure. The hydraulic
gap width of joints is mainly 0. 15-0. 21 mm,and the ratio of average geometric gap width to hydraulic gap width is
mainly 3. 6-26. 9,which increases with the increase of filling degree. When the filling degree is 0,the joint wear area decreases
with the increase of seepage water pressure. Under the same seepage water pressure,the residual fillings of joints increase with
the increase of filling degree,and the fillings mainly remain in the key ups and downs of joints. The research results can provide
key parameters for the stability calculation of jointed granite slopes containing kaolin fillings under rainfall conditions,and can
also provide the basis and reference for the study of joint shear-seepage coupling mechanism for the study of the precursory criterion
of such slope instability.

Key words: granite slope,filled joint,shear-seepage coupling,filling degree,seepage pressure