石灰岩高速滚动摩擦特性

Tribological characteristics of high-speed rolling limestone

滑面的摩擦特性是高速岩质滑坡动力学研究的关键问题之一。以典型脆性灰岩为研究对象,借助滚动磨损试验设备,开展不同压力和转速条件下干燥和湿润灰岩的滚动摩擦试验,研究岩石动态摩擦特性(摩擦系数和磨损率)。试验结果表明,干燥和湿润岩石的滚动摩擦系数分别与摩擦速率呈负相关和正相关,与法向压力关系不明显。对于干燥灰岩,滚动试件(滑体)和静止试件(滑床)的磨损率与摩擦速率分别呈正相关和负相关。对于湿润灰岩,磨损率与摩擦速率呈正相关。基于Hertz弹性接触理论,推导出摩擦斑处的最大压应力和拉应力,进而提出相应条件下脆性灰岩的摩擦碎裂机制。结论可为灰岩高速滑坡防灾减灾提供设计参数。

Frictional characteristics of sliding planes are the critical issues in the kinetics of high-speed rockslides. The friction experiments of dry and wet limestone samples at different pressures and rolling velocities are conducted to investigate dynamic frictional characteristics （i.e., friction coefficient and wear rate） using the rolling wear test equipment. Experimental results show that for dry limestone, there is a negative correlation between the rolling friction coefficient and the rolling velocity, but it is a positive relationship for wet limestone. Whether the specimen is dry or wet, there is no apparent relationship between the rolling friction coefficient and the normal pressure. For dry limestone, the wear rate of rolling specimen （i.e., as sliding mass） and static specimen （i.e., as sliding bed） is positively and negatively correlated with the rolling velocity, respectively. However, for wet limestone, the wear rate is positively relevant to the rolling velocity. In addition, based on the Hertz Elastic Contact Theory, we deducted the maximum compressive and tensile stresses of the friction spot, and then proposed the friction-fragmentation mechanism of brittle limestone under corresponding conditions. This study can provide the design parameters for the disaster prevention of the high-speed limestone rockslides.