Research on the simulation of blasting damage and its mechanism of deep tunnel excavation
LUO Sheng1，2，YAN Peng1，2，LU Wenbo1，2，CHEN Ming1，2，WANG Gaohui1，2
(1. State Key Laboratory of Water Resources and Hydropower Engineering Science，Wuhan University，Wuhan，Hubei 430072，China；2. Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering，Ministry of Education，
Wuhan University，Wuhan，Hubei 430072，China)
Abstract：Damage induced by blasting excavation influences the surrounding rock state，which directly affects the construction safety and support design. The effect of stress filed has on blasting damage mechanism has not been fully revealed，and the existing damage simulation method has deficiencies in simulating large-scale explosion. Based on the excavation in the auxiliary tunnel of Jinping II hydropower station，a method of blasting damage simulation based on the normal direction impact load is proposed. And the simulation and field detecting test results is compared to verify the feasibility of the simulation method. Meanwhile，the method is adopted to discuss the influence ground stress has on damage zone. The results indicated that the damage zone can be effectively simulated by the normal direction impact load，and the ratio of the maximum mesh size to the minimum mesh size can be reduced by 82% and the calculation time can be reduced by 50% to 87%. The results also show that the blasting damage depth of tunnel excavation has a significant correlation with the in-situ stress level，and the damage depth increase after decreasing with stress level increases. And the reason why the ground stress "inhibited" the blasting damage zone was due to the fact that when the damage zone was simulated with ground stress，the application of the blast load increased the yield limit of the surrounding rock to some extent；under the conditions of the study of this paper，when the ground stress level is low(less than 12.5 MPa)，the shearing damage is the main part of blasting damage，while the local stress level continues to increase，shear damage is inhibited，and the blasting mainly causes pure shearing damage.
罗 笙1，2，严 鹏1，2，卢文波1，2，陈 明1，2，王高辉1，2. 深埋隧洞开挖爆破损伤数值模拟及损伤机制研究
[J]. 岩石力学与工程学报, 2021, 40(S1): 2760-2772.
LUO Sheng1，2，YAN Peng1，2，LU Wenbo1，2，CHEN Ming1，2，WANG Gaohui1，2. Research on the simulation of blasting damage and its mechanism of deep tunnel excavation . , 2021, 40(S1): 2760-2772.
2021, Vol. 40 
