Study On The Laws Of Seepage And Shear Of Single Jointed Rock Masses Under Water-rock Interaction

The study of mechanical properties of jointed rock masses has always been a research hotspot in geotechnical engineering,and the study of mechanical properties of jointed rock masses under the water-rock interaction is one of the most important aspects.Based on the study of water-rock interactions in the previous reservoir area,this paper takes the jointed rock masses of the typical bank slope in the Three Gorges reservoir area as the research object.The water-rock interaction test of jointed rock was carried out,and the shear characteristics and seepage characteristics of jointed rock in the fluctuating zone were studied in detail.The key point is that the test methods and test conditions are more realistic to simulate the repeated fluctuations of the water level in the storage zone and the actual occurrence environment of the soaking-drying cycle.1)The method of calculating joint surface roughness coefficient JRC based on fractal dimension of the joint surface was proposed.The relationship between the permeability coefficient of the jointed rock and the roughness coefficient of the joint surface JRC was established based on the seepage test and microscopic scan test.The results show that the correlation between the joint permeability coefficient under different confining pressures and the joint surface roughness coefficient JRC can be fitted by exponential function,and the fitting condition is better.2)The seepage test under water-rock interaction was carried out.The variation law of the unit seepage,equivalent hydraulic aperture and permeability coefficient of single jointed rock under water-rock action was analyzed.The deterioration equation of permeability coefficient of the single jointed rock was established.The study finds that the unit seepage,equivalent hydraulic aperture and permeability coefficient of single jointed rock masses under different confining pressures increase with the increase of the number of dry-wet cycle,and the overall trend is “first steep and then slow”.In comparison,the penetration characteristics of the joint surface under the first eight water-rock interactions increased significantly,and the latter trend gradually became flat.3)The repeated shear tests under water-rock interaction were designed and carried out and shear strength of single jointed rock was modified.The analysis shows that the parameters of shear strength and shear strength of single joint rock masses under water-rock interaction was analyzed.The deterioration equation of shear strength of single joint rock masses under water-rock interaction has been established.The results show that the shear strength of single jointed rock mass under different normal stresses gradually decreases with the increase of the wet-dry cycle,and the overall trend is “first steep and then slow”.In comparison,the shear strength of the joint surface caused by the first 8 water-rock interactions deteriorated significantly,and the post-deterioration trend gradually became flat.4)The micro-morphological characteristics of the joint surface under water-rock interaction are first steeped and then slowed through the three-dimensional scanning analysis.And the correlation between the micro-morphology of the joint surface and the shear and seepage characteristics of the single jointed rock masses under water-rock interaction is analyzed.It also analyzes and explains the degradation mechanism of the single jointed rock masses under the action of dry-wet cycle.