The typical experiment apparatus of rock friction sliding was designed and improved. Under low normal stress
the static friction coefficients for 8 silicate rocks were studied experimentally based on the apparatus. The surface topography of the sliding surface was characterized by the statistic parameters and asperity; and the influence of roughness parameter on static friction coefficient was analyzed. When the sliding surfaces are polished
the static friction coefficients of phyllite
quartzite
lithic sandstone
and quartz sandstone are 0.38-0.47; and the ones of conglomerate
gravelly coarse quartz sandstone
medium grained lithic sandstone
and medium grained quartz sandstone are 0.83-1.07. The two roughness parameters which are the maximum depth of profile valley (Rm) and the maximum height of profile peak (Rp) make the asperity produce different actions and induce to different static friction coefficients. With the increment of the two roughness parameters
the static friction coefficient is increased with exponential law. The amounts of asperity are less on the sliding surfaces of phyllite
quartzite
lithic sandstone
and quartz sandstone. The amounts are more on the ones of conglomerate
gravelly coarse quartz sandstone
medium grained lithic sandstone
and medium grained quartz sandstone. With the increment of asperity amounts
the static friction coefficient is increased during rock frictional sliding.