Morphology Change And Stress Evolution Of Rock Joint Surface In The Process Of The Shear

Joint surface is usually weak plane of rock mass, in the practical engineering rock mass destruction mostly caused by joints, and joint surface geometry is an important factor of controlling rock mass mechanics. Based on this, this paper mainly studies the shape and the random rules in the shape of joint surface morphology and the evolution rule of stress in the process of shear, the main results were as follows:(1) in the process of the shear jagged joint surface morphology changes:Morphology of root mean square and the height of slope root mean square change rule is:the early more gentle, bluff type after falling, finally reaching steady; Auto-correlation function curve is almost unchanged .(2) the shear jagged joints and the stress in the process of evolution:The tensile stress in the vicinity of joint plane curve is ups and downs wavy, its most peaks at about 0.5·?n.The press stress in the vicinity of joint plane rectangular pulse shape curve, the curve of the lower limit value is about-2.5·?n. .Rectangular pulse shaped contact pressure stress curve, curve approximation for the cycle with constant amplitude of oscillation change,fluctuation range is (0.2 ?1.5)·?n.Shear stress curve of the rectangular pulse shape and curve,the range is f·(0.2?1.5)·?n.Morphology change's contribution to the shear stress is 0.2·?n·f.The ratio of shear stress and contact stress for the coefficient of friction.Minimum joint surface contact area and the ratio of total contact area of 26.7%. The joint surface periodic open distance.(3 )JRC curve in the process of shear joint surface morphology change:The height of the morphology of RMS, RMS of slope,Auto-correlation function,gradually decreases, and finally tends to be stable.(4) the JRC curve shape in the process of shear stress evolution of the joint:Different shape the tensile stress and press stress in the vicinity of joint surface vary enormously;Same shape the press and tensile stresses in the vicinity of joint plane law, its position was close to a peak, peak point its value is larger, as far away from the peak point of their value to converge to zero.Different shape of contact stress and shear stress are very different; The same morphology of contact pressure stress and shear stress law of similar and peak position close to appear.The peak point of contact stress and shear stress and its value is larger, as far away from the peak point of their value to converge to zero.The entire process of shear stress curve of peak number gradually reduce. At the same shear test is the following the ratio of shear stress and contact stress for the coefficient of friction.For open distance change:curve has risen sharply to the peak point, fell again, finally reaching the level.Different JRC joint topography contact area curve change rule of basically the same, the contact area and the shear displacement can be for curve fitting y= axb.