微凸体对抛光岩石表面静摩擦系数影响试验研究

对典型岩石摩擦滑动试验装置进行了改进，以8种硅酸盐岩作为研究对象，在低正应力条件下对岩石摩擦滑动过程中的静摩擦系数进行了试验研究。对滑动表面形貌进行了表征，从统计学角度分析了粗糙度对静摩擦系数的影响，并基于滑动表面微凸体（凹凸体、微观粗糙度）对这一影响作进一步分析。研究表明：滑动面为抛光面时，千枚岩、石英岩、岩屑砂岩和石英砂岩的静摩擦系数为0.38～0.47，砾岩、含砾粗粒石英砂岩、中粒岩屑砂岩和中粒石英砂岩的静摩擦系数为0.83～1.07；在粗糙度中，轮廓最大谷深Rm和轮廓最大峰高Rp两个参数导致摩擦滑动中产生不同静摩擦系数，且随着这两个参数的增加，静摩擦系数呈指数规律增加；千枚岩、石英岩、岩屑砂岩和石英砂岩滑动表面的微凸体数量较少，砾岩、含砾粗粒石英砂岩、中粒岩屑砂岩和中粒石英砂岩滑动表面的微凸体数量较多，随着微凸体数量的增加岩石摩擦滑动过程中的静摩擦系数增加。

Experimental study of influence of asperity on static friction coefficient for polished rock surface

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.