Fractal Description On Shear Strength Of Cement Face Of Rock-Concrete And Its Engineering Application

The stability analysis of rock engineering is the core of research subject in rock mechanics. Stability against sliding of large constructions on bedrock usually is controlled by shear strength of concrete-bedrock cement face. And shear strength of concrete-bedrock cement face is influenced with many factors, in which roughness of cement interface is an important factor.Taking suspension bridge anchor of Runyang Highway Bridge as project background in this paper, considering undulating angle of rock mass structural plane, angle of mean square root slope method is established by exerting fractal geometry theory. Fractal dimension of profile of rock mass structural plane is calculated by above method. And roughness degree is described quantitatively, furthermore correlativity between fractal dimension and roughness coefficient (JRC) is analyzed. By means of a mass of shear strength test of rough cement face of concrete-bedrock, influences of cement face roughness of two mediums on shear strength parameter, shear deformation characteristics, shear failure mechanics are systemically studied. Empirical relationship between fractal dimension of cement face roughness and shear strength parameters is established. According to the method in paper, roughness of bedrock surface of north anchor pit of Runyang Bridge is described in quantitative fractal dimension, and the method of determining frictional resistance of the whole anchor under many factors is discussed, which offers a new ideal and approach for precise determination of frictional resistance of rock mass engineering.On basis of experimental analysis, several conclusions can be indicated that: roughness of cement face or structural plane can be described well quantitatively with fractal dimension in paper. Roughness increases inner friction angle and cohesive force, and transfers characteristics of shear deformation curve and mechanics and form of shear failure. Studying deeply on shear strength characteristics of rough cement face has an important meaning for precise determination of shear strength parameter and analysis on failure mechanics.