Abstract In order to analyze the stability of surrounding rock under drilling and blasting excavation of layered rock mass tunnel, the dynamic response characteristics of the tunnel support system under different bedding angles are studied with the LS-DYNA numerical simulation method. The results show that : (1) When the bedding angle of surrounding rock is 60°, the peak vibration velocity along horizontal tangential direction of the vault at 25 m behind the tunnel face increases by 1.74 times. (2) The asymmetric vibration mechanism of particles is present at left and right hances and side walls under different bedding angles of surrounding rock. (3) The horizontal radial and vertical peak vibration velocities at left and right hances and side walls under different bedding angles show a U-shaped change trend with the increase of the distance from the tunnel face. (4) The asymmetric stress coefficients of lateral and vertical compressive stresses at the hance position show a significant turning point when the bedding angle of the surrounding rock is 60°, showing a trend of rapid increase at first and then rapid decrease. (5) As the bedding angle of surrounding rock layer changes from 0° to 90°, the peak dynamic tensile stress of the bolt shows a trend of increase at first and then decrease. The circumferential distribution of the peak dynamic tensile stress of the bolt shows inconsistency with the change of the bedding angle of surrounding rock. The on-site monitoring results show that the particle vibration law of the anchor support structure caused by tunnel blasting at a 30° bedding angle of surrounding rock is consistent with the research results.
Abstract：
In order to analyze the stability of surrounding rock under drilling and blasting excavation of layered rock mass tunnel, the dynamic response characteristics of the tunnel support system under different bedding angles are studied with the LS-DYNA numerical simulation method. The results show that : (1) When the bedding angle of surrounding rock is 60°, the peak vibration velocity along horizontal tangential direction of the vault at 25 m behind the tunnel face increases by 1.74 times. (2) The asymmetric vibration mechanism of particles is present at left and right hances and side walls under different bedding angles of surrounding rock. (3) The horizontal radial and vertical peak vibration velocities at left and right hances and side walls under different bedding angles show a U-shaped change trend with the increase of the distance from the tunnel face. (4) The asymmetric stress coefficients of lateral and vertical compressive stresses at the hance position show a significant turning point when the bedding angle of the surrounding rock is 60°, showing a trend of rapid increase at first and then rapid decrease. (5) As the bedding angle of surrounding rock layer changes from 0° to 90°, the peak dynamic tensile stress of the bolt shows a trend of increase at first and then decrease. The circumferential distribution of the peak dynamic tensile stress of the bolt shows inconsistency with the change of the bedding angle of surrounding rock. The on-site monitoring results show that the particle vibration law of the anchor support structure caused by tunnel blasting at a 30° bedding angle of surrounding rock is consistent with the research results.
YU Jianxin LIU Wenjin WANG Jinxing LIU Huanchun ZHOU Zhibin
.Study on Vibration Influence of Layered Rock Mass Tunnel Blasting on Support System[J] MODERN TUNNELLING TECHNOLOGY, 2023,V60(5): 99-110
2023, Vol. 60 