Study of restricted fractures in veins and dykes, and associated stress distribution

Studying fractures in rocks is crucial for understanding the driving mechanism, stress distribution, and strength of the materials. In this present study, we aim to understand the fracturing susceptibility of long linear veins and dykes, which are often replete with fractures within them. These fractures are found to be restricted within these veins and dykes that act as rigid bodies. We consider this rigid body an inclusion embedded in an infinitely homogeneous matrix. A 2D FEM model has been used to conduct the present study, where the model results are obtained for different boundary conditions. To understand the response of the model with respect to various physical and mechanical properties, the stresses are computed and plotted against the applied conditions, which in turn represent the fracturing susceptibility. When the inclusion is placed perpendicular to the applied maximum compressive stress, the intra-inclusion stress becomes tensile, producing restricted tensile fractures. As the inclusion is rotated from this position beyond a critical angle of 28°, the intra-inclusion state of stress becomes compressive. Since the applied minimum compressive stress increases in magnitude, both tensile and shear fracture susceptibility within the inclusion decreases. Consequently, these model results are integrated to comment on the restricted fracturing in veins and dykes (competent layers) bounded by incompetent host rock (matrix).