Crack Propagation And Reasonable Cloth Anchor The Pilot Study

Rock, concrete, ceramics and glass, as discontinuous inhomogeneous, anisotropic, and not elastic brittle medium, are typically made up of defected material containing flaws. Under different compressive stress, as the crack initiation, propagation, coalescence and interaction, the flaws may lead the strength and stiffness degradation of such medium. It is significant for engineering and academic study to investigate the rock failure process of medium containing flaws.In classical fracture mechanics, the research of crack growth only involves crack propagation caused by stress concentration from flaw tip, and the study of crack growth in inhomogeneous medium may meets mathematical difficulty, so it is deficient to get accurate analytical description .To study the crack growth in inhomogeneous medium with numerical method, the result is not according with the fact well. Experimental method is a powerful tool to solve the crack growth problem. In this paper, the two methods are combined to do the following research work:1 The echelon cracks with different distributing forms in two-dimension condition were simulated using the RFPA^2D developed by the DongBei University. The influence of different distributing forms on the sample strength and crack propagation pattern were studied only changing the distance between internal nodes in the cracks.2 Trying a great amount of mortar material with different proportion , and testing compressive&tensile strength value, Poisson's ratio, elastic module of different samples, a material with fine brittleness were found out.3 Mortar material specimens containing flaws with developed material by myself, were made, Then we do some research about failure process of mortar material specimens which contain different angle single ellipse flaw and influence of flaw angle on the strength of mortar material., using acoustic emission equipment and serve-controlled test machine.4 Base on the research about ellipse flaw propagation at a = 45 ° , setting two bolts which angle is 45° and 90° with flaws in middle and end of flaws, the effect of bolting on propagation of rock crack in uniaxial compression were researched and the effect of different bolting on the enhancement of mechanics capability were summarized. Then we give some advice about reinforce with bolts in engineering.