Mechanical properties and fracture evolution of V-shaped intersecting fractured sandstone under dry and saturated conditions

Abstract

The distribution pattern of cracks within a rock mass significantly influences its mechanical properties and the evolution of fracture processes. Additionally, the presence of groundwater can adversely affect the rock mass, thereby affecting the stability of rock engineering structures. To investigate the effects of the angle between V-shaped intersecting cracks and groundwater on the mechanical properties and fracture failure modes of sandstone, uniaxial compression tests were performed on both dry and saturated sandstone samples. The findings reveal that while both intersecting cracks and groundwater contribute to the deterioration of sandstone properties, the primary influence on the mechanical behavior of the samples is attributed to the intersecting cracks themselves. Specifically, the trends in fracture initiation stress, peak stress, and elastic modulus of sandstone with V-shaped intersecting cracks, under both dry and saturated conditions, exhibit a similar pattern, characterized by an initial increase followed by a subsequent decrease as the fracture angle increases. Furthermore, the failure mode observed in sandstone samples with V-shaped intersecting cracks is predominantly tensile failure, mirroring the crack patterns identified in samples featuring inclined single cracks. Notably, the presence of groundwater alters the failure mechanism of sandstone samples with V-shaped intersecting cracks, transitioning it to a tensile-shear failure mode while also reducing the incidence of far-field cracking and surface peeling in the samples.