Theoretical analysis of dynamic stress distribution around a circular damaged roadway under transient disturbance

Abstract

Excavation damaged zone (EDZ) widely exists in the surrounding rock of underground roadway due to blasting excavation, which can further change the surrounding rock property and deteriorate the stability of the roadway. In the presented research, a damaged roadway model was developed to investigate the dynamic stress concentration factor (DSCF) distribution around the damaged roadway under a transient plane P wave. The influencing factors on DSCF distribution were discussed, including the shear modulus (μe/μd) of the intact surrounding rock to that of the damaged surrounding rock, the thickness of EDZ (Rd/R0), and the wavelength of the incident stress wave. Results indicated that the damaged surrounding rock around the roadway belongs to stress‐relaxed zones, and the existence of EDZ can reduce the overall DSCF of surrounding rock. As the ratio of μe/μd is increasing, both the maximum compressive and tensile stress concentrations in the damaged zones decrease gradually, which is opposite to that in the intact surrounding rock. A larger EDZ can induce a higher DSCF in the damaged surrounding rock and a smaller DSCF in the intact surrounding rock. As the incident stress wave's wavelength is increasing, the peak value of DSCF grows first before declining, finally followed by a constant value. Furthermore, the maximum compressive and tensile stress concentrations are always found near the surrounding rock that is perpendicular to and along the incoming direction of stress waves, respectively. The stress concentration in both intact and damaged surrounding rock near the incoming side of stress waves is higher than that at the transmitted side.

Influence of Incident Orientation on the Dynamic Response of Deep U-Shaped Cavern Subjected to Transient Loading

“…Yi et al [19] obtained the distribution characteristics of the dynamic stress concentration factor around a lined cavern based on theoretical calculations and pointed out that the incident wave frequency, bonding parameters, and distance of disturbance sources have a significant influence on the dynamic responses around the cavern. Zhao et al [20] investigated the dynamic stress distribution around a circular cavern by theoretical analysis and numerical simulation. Their findings showed that the existence of the excavation damage zone reduces the dynamic stress concentration around the cavern, and the dynamic stress concentration factor around the intact surrounding rock decreases with the increasing thickness of the damage zone.…”