Study on the Damage Evolution of Weathered Granite under Different Confining Pressure Based on Hoek-Brown Failure Criterion and Acoustic Emission Parameters

Abstract

Abstract The stability of the mine construction is significantly impacted by weathered granite (WG), which presents a significant risk to the security of workers and equipment. In order to investigate the strength characteristics of WG under different confining pressures, acoustic emission (AE) and scanning electron microscopy (SEM) tests were performed on WG under triaxial compression. The relationship between strength evolution and different confining pressures of WG is studied. Under various confining pressures, the variation regularity of the AE parameters of rock samples was examined. Additionally, the microscopic morphology of rock samples is investigated using SEM. The results show that increased confining pressure suppresses WG damage development before the stress peak and switches to promoting damage development following the stress peak. The axial strength is quantitatively analyzed before the WG stress peak using the Hoek-Brown failure criterion, and the axial damage threshold stress under different confining pressures is obtained. Furthermore, the axial damage threshold stress point is clearly increased in the AE ring count rate and energy rate curves of WG at various confining pressures. The last effect of water on WG is microstructural weakening, which manifests itself in the swelling and erosion of the structure by water.