The Study Of Frictional Sliding Characterd Of Rocks And Influencing Factors

The influencing factors about the frictional sliding rocks were systematic and generally analyzed. The influencing mechanism about frictional sliding of rocks and stabilization were studied from the microscomic degree.The objects of study are twelve experimental samples, including phyllite, quartzite, quartz sandstone, lithic sandstone, marble, limestone, lite limestones, dolomitic limestone, conglomerate, gravelly coarse quartz sandstone, medium grained quartz sandstone, medium grained lithic sandstone, respectively. The typical friction experiment apparatus of rock frictional sliding was devised and reformed. The experimental condition was under nature state, moisture state and dry state at low normal force (σ<5MPa),. The properties of the rock frictional sliding including static frictional coefficient μ, dynamic frictional coefficient μd, and constitutive parameter (a-b) in different states were experimentally studied. The influencing factors are mainly inter factors of the samples, which are roughness parameters, mineralogical composition, pore structure, and grain.The roughness parameters of the surface topography in the rock sliding were analysized by American MicroXAMTM ADE3dimension white light interferometry optical interferometer. The mineralogical composition, pore structure, and grain of the experimental samples were analysized by SHIMADZU XRD-6000X-ray diffactometer and μCT225kVFCB Micro-CT experimental system. The size of grain was computed with Scanning Probe Image Processor (SPIP). The relation between the properties of frictional sliding and the influencing factors were analyzed. The main research results are as follows: 1. The frictional theory, experimental method, scale of study, mode, experimental phenomena and the analysis for results were systematically summarized during the rock frictional sliding. The theory includes in Amontons law, Byerlee law, asperity, and adhesion. The experimental methods of the measurements of rock frictional sliding are respectively typical friction experiment, direct shear, double shear, rotary shear, and triaxial experiment. The analysis for the scale of experimental samples, the phenomena of steady sliding and stick slip, the conversion of the two sliding modes, static frictional coefficient μ and dynamic frictional coefficient μd, constitutive parameter (a-b), stability criterion, and the interreaction for internal system. The internal factors effecting the frictional sliding of rocks are the surface topography of rock sliding surfaces, mineralogical composition, pore structure, and size of grain. The necessary condition for the steady of rock frictional sliding is velocity-weakening.2. The surface topography of rock sliding surfaces is characterized with statistic parameters and fractal dimensions. After the sliding surfaces were polished, the roughness parameters including in arithmetical mean deviation of the profile Ra, root mean square deviation of the profile Rq, and average value of the surface roughness parameter R are identical, however, the other parameters, such as, maximum depth of porfile valley Rm and maximum height of profile peak Rp are not identical. With the increment of R and the fractal dimension D, the static friciton coffeciment μ under different states exponentially increased, and the constitutive parameter (a-b) linearly increased.3. Under different states, the mode of the mono-mineral rock frictional sliding about the silicate rock and carbonate rock is stick-slip, and water has no effect on the sliding mode. The mode of the multi-mineral rock frictional sliding about the two rocks is steady sliding and stick-slip, and water can transform the sliding mode from steady sliding to stick-slip. The static friciton coffeciment μ of the mono-mineral quartz silicate rock and calcite carbonate rock is less than that of multi-mineral rock under corresponding states, repecitvely. Under moisture state, with the contents of the brittle calcite mineral and the ductile clay mineral increased, the constitutive parameter (a-b) decreased in exponential law.4. Micro-CT digital images are processed by Matlab processure. The law of the porosity variation with the pore aperture of rocks is estimated by the digital image processing. The parameters Ra, Rq, R for the surface roughness are governed by the mineralogical composition and pore structure of rocks, the two parameters Rm and Rp are governed by grain parameter, especially, mean height of the profile. With the increment of the mean height of the profile, the Rp increased as a linear law. With the increment of the porosity and grain of rock sliding surfaces, the frictional coefficient changes by linear law, under the nature, moisture, and drying states.