Numerical Analysis of Mechanical Properties of White Sandstone Granite Composite Rock Mass with Prefabricated Cracks

Ti Su

doi:10.54691/dv067180

Authors

Ti Su

DOI:

https://doi.org/10.54691/dv067180

Keywords:

Mixed rock mass; Prefabricated cracks; Mechanical properties; Damage evolution; destruction mode.

Abstract

The development and propagation of fractures within rocks have a significant impact on their mechanical behavior and engineering stability. This study focuses on composite rock masses composed of sandstone and granite and uses the PFC2D numerical simulation platform based on the discrete element method to systematically investigate the mechanical responses, damage evolution, and failure patterns of composite rock masses containing pre-existing fractures under uniaxial compression. By constructing models of pre-existing fractures with different inclinations 0°, 15°, 30°, 45°, 60°, 75° and lengths 10 mm, 15 mm, 20 mm, 25 mm, the influence of fracture geometric parameters on peak strength, peak strain, elastic modulus, and crack propagation paths of the rock masses was analyzed. The results indicate that when the fracture inclination is 30°, both the peak strength and peak strain of the rock mass are lowest, showing the most significant degradation effect; when the inclination is 75°, the mechanical performance of the rock mass is optimal. The influence of fracture length is regulated by the inclination: at 30°, the elastic modulus decreases with increasing fracture length, while at 60°, the effect is not significant. The crack initiation location and final failure mode exhibit regular evolution with changing inclination, with 45° being the optimal angle for shear-through failure.

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