微凸体形状对砂岩节理摩擦因数的影响研究

Influence of asperity shapes on friction coefficients of sandstone joints

为分析微凸体形状对砂岩滑动稳定性的影响,采用自制摩擦滑动装置对砂岩节理进行滑动摩擦试验,将砂岩表面微凸体形状考虑为规则正多边形,引入微凸体形状系数参数,建立包含微凸体参数的摩擦因数预测模型。结果表明:微凸体长度越大,摩擦因数越小,变化范围越窄。微凸体长度一定时,微凸体形状系数越大,摩擦因数越小;微凸体形状系数不变时,微凸体长度越大摩擦因数越小。当微凸体长度取值在2~5 mm之间时,摩擦因数预测值与试验值吻合较好。

In order to analyze influence of asperity shapes on sliding stability of sandstones,a sliding friction test was performed on a self-made device.With asperity shapes of sandstone surface being considered as a regular polygon and asperity shape coefficient being introduced,a prediction model for friction coefficients of sandstone joints,including asperities,was proposed.The results indicate that along with increase in asperity's length,friction coefficients gradually decrease,and their variation range becomes narrower.When the length is constant,friction coefficients gradually decrease with the increase of asperity shape coefficient.And in the case of constant asperity shape coefficient,friction coefficients gradually decrease with increase of length.The predicted friction coefficient is in good agreement with test value when the length is between 2-5 mm.