Numerical investigation on origin and evolution of polygonal cracks on rock surfaces

We studied the formation and evolution mechanism of polygonal cracks on rock surfaces under cooling by modelling meso-damage mechanics, continuum mechanics thermodynamics. Factors that affect surface damage include ambient temperature, lithology difference boundary restrictions. established simulated a heterogeneous model with weak layer for three types boundaries. These were biaxial constraint, uniaxial constraint free boundary. The initiation propagation reproduced varying thickness homogeneity layer. results show constraints strongly influence cracking. Many or parallel are generated constraint. unconstrained displays at center in surrounding areas. thicker layer, larger average area formed blocks. Small blocks short more numerous than large long cracks. As heterogeneity index increases, is likely to produce relatively regular shapes. Quadrilateral, pentagonal hexagonal dominate regardless changes heterogeneity. However, number edges sensitive polygons tend become complex increasing inhomogeneity. This study contributes understanding mechanisms nature. Additionally, simulations three-dimensional fracture geometry provide basis developing algorithms generate discrete fractures network (DFN) analyses.