Plane Shear Crack (fault) Of The Interaction

Studies on two typical faults system with numerical simulating method are presented.For the first time, the computation of Stress Intensity Factors (SIF) and stress tensors by global crack-line displacement fitting is introduced, improving the accuracy of calculation. Using Boundary Element Method to obtain Crack Opening Displaccment (COD) data, then using global crack-line displacement fitting to obtain SIF and stress .tensors. This method is less post processing, more reliable, Iess time consuming and easy to put into prachtice. It can be applied to mixed mode arbitrary crack problems. The method is tested and verified in this paper.The application of the method to two typical cases of two-dimensional two equal lengthcracks is described in this paper. The first one is about two dimensional collinear shear cracks,mainly discussing the interaction between the cracks under loading. The quantitative relationships between the SIF at the tip and the ratio of the distance between two cracks to the length of the cracks are presented. Meanwhile, the stress distributions corresponding to several geometrical shapes of the cracks are also presented, with discussion of what conditions can easily make thecracks break.The second one is about two dimensional two parallel shear cracks. In this case, theinteraction between two cracks depends not only on the ratio of tangential distance between two cracks to the length of cracks but also on the ratio of normal distance between two cracks to the length of the cracks. Quantitatively, the relationships between SIF distribution and the different combinations of vertical distance and horizontal distance are presented. On the other hand, the stress distributions under several special geometrical conditions are discussed, describing how theinteraction between cracks affects the crack breaking. Experimental results are introduced as the qualitative verification.