Excavation damage of surrounding rock of deep high-temperature chamber

ZHOU Xunqian; LIU Jianfeng; JIANG Haibo; XIE Liangfu; LI Hongtao; ZHOU Jiawen; LU Gongda

Abstract：The high-stress and high-temperature issues of deep engineering pose significant challenges to deep resource exploitation and underground space utilization.By establishing a numerical model for the entire process of blasting-unloading-cooling and embedding a rate-dependent rock constitutive model to reflect the dynamic and static mechanical responses of the rock mass,the temporal and spatial evolution of excavation damage under dif-ferent stress and geothermal conditions are analyzed.The results indicate that during dynamic excavation,the sur-rounding rock underwent initial dynamic damage due to blasting,unloading,or both,and the thermal stress in-duced by chamber ventilation cooling caused additional thermal damage within the rock mass.Under hydrostatic pressure conditions,dynamic rock damage shows an evolution trend of initially weakening and then strengthening with the increase in geostress level,while cooling damage continuously increased with the increase in geostress.Under non-hydrostatic pressure conditions,dynamic rock damage near the chamber's crown and arch foot exhibit-ed a trend of initially decreasing and then increasing with the increase in lateral pressure coefficient and a mono-tonically increasing trend,respectively.During the ventilation phase,the cooling effect does not induce thermal damage in rock mass near the arch foot,but cooling damage in surrounding rock near the crown gradually in-creased with the increase in lateral pressure coefficient.