高速岩质滑坡滑面滑动摩擦特性研究——以王山抓口寺滑坡为例

Study on sliding tribological characteristics of the sliding plane of a high-speed rockslide:taking the Wangshan-Zhuakousi rockslide as instance

高速岩质滑坡滑面摩擦特性是其运动机制的重要方面,目前尚未研究透彻。以四川省峨眉山市的王山-抓口寺滑坡为研究对象,通过野外地质调查和视频监控,获取了滑坡工程地质条件和滑坡运动特征。利用销盘式磨损仪对滑体(玄武岩)和滑面(凝灰岩)分别进行高速摩擦试验,分析其在干燥和饱水状态下的摩擦特性(动摩擦系数和微观磨损形貌)。结果表明:滑面(玄武岩和凝灰岩接触面)的动摩擦系数远小于滑体(玄武岩)的动摩擦系数;在试验条件下,无论饱水或干燥状态,滑面(玄武岩和凝灰岩接触面)的动摩擦系数与摩擦速率和法向压力均负相关;在试验条件下,无论饱水或干燥状态,滑体(玄武岩)的动摩擦系数与摩擦速率负相关,但与法向压力正相关;高速摩擦过程中,滑面的剪胀破裂会导致动摩擦系数瞬间增大。试验结论可作为含软弱夹层的硬岩滑坡形成高速运动的一种原因,同时可为玄武岩和凝灰岩地区高速岩质滑坡的防灾减灾提供设计参数。

In order to characterize the transportation mechanism of the high-speed rockslide,it is significant to investigate the tribological characteristics of the sliding surface.However,the investigation of tribological characteristics has not been thoroughly revealed.Taking the Wangshan-Zhuakousi rockslide in Emeishan city of Sichuan province as instance,the engineering geological conditions and the motion characteristics of the rockslide were obtained through field geological survey and video surveillance.Based on the high-speed friction experiments of the rockslide masses(basalt)and the sliding plane(tuff)by the pin and disc worn instrument,the tribological characteristics(dynamic friction coefficient and microscopic wear surface appearance)were analyzed under dry and saturated conditions.The results show that:the dynamic friction coefficient of the sliding plane(the interface between basalt and tuff)is much smaller than that of basalts.Regardless of the dry and saturated conditions,the dynamic friction coefficient of the sliding plane(the interface between basalt and tuff)is negatively correlated with both the frictional velocities and the normal pressures in the experiments.Regardless of the dry and saturated conditions,the dynamic friction coefficient of sliding mass(basalt)is also negatively correlated with the frictional velocities,whereas it is positively correlated with the normal pressure in the experiments.In the high-speed friction process,the dynamic friction coefficient is increased instantly due to the dilative shear failure of the sliding surface.The experimental results can be adopted for explaining the high-speed motion of the hard rockslides containing the weak interlayers.In addition,the findings in this study can provide essential design parameters for disaster prevention and high-speed rockslide mitigation in the tuff and basalt areas.