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Study on Deformation Control Technology for Unsymmetrically Loaded
Tunnels in Bedding Strata under High Geo-stress
(1. China Railway 17th Bureau Group Fourth Engineering Co. Ltd., Chongqing 401121; 2. School of Civil Engineering, Central South University, Changsha 410075; 3. National Engineering Research Center for High-speed Railway Construction Technology,Changsha 410075)
Abstract During the construction of Ganzhuang Tunnel on the China/Kunming-Laos/Vientiane Railway, large de?
formation occurred due to high geo-stress and unsymmetrical load in bedding strata, which resulted in the cracking of tunnel primary support, block dropping and clearance invasion. Aiming at the large deformation of Ganzhuang tunnel, based on the three bench excavation method, a modified short bench construction control technology is proposed, and the block discrete element software 3DEC is used to carry out numerical simulation of tunnel excavation under different bench heights and lengths. The results show that the bench parameters have a significant effect on the deformation of the unsymmetrically loaded tunnel in bedding strata. When the height of the middle bench decreases from 4 m to 2 m, the tunnel deformation convergence decreases rapidly; When the length of the middle bench is less than 15 m, the deformation convergence of the tunnel decreases gradually with the increase of the length of the middle bench. When the middle bench length is greater than 15 m, the tunnel deformation convergence tends to be stable, and the tunnel deformation convergence is about 21 cm. The height of the middle bench in the bedding unsymmetrical loading section of Ganzhuang tunnel should be set at about 2 m, and the length of the middle bench should be controlled at more than 15 m. Field monitoring data show that this construction control technology has achieved good deformation control effect in Ganzhuang tunnel.
Abstract：
During the construction of Ganzhuang Tunnel on the China/Kunming-Laos/Vientiane Railway, large de?
formation occurred due to high geo-stress and unsymmetrical load in bedding strata, which resulted in the cracking of tunnel primary support, block dropping and clearance invasion. Aiming at the large deformation of Ganzhuang tunnel, based on the three bench excavation method, a modified short bench construction control technology is proposed, and the block discrete element software 3DEC is used to carry out numerical simulation of tunnel excavation under different bench heights and lengths. The results show that the bench parameters have a significant effect on the deformation of the unsymmetrically loaded tunnel in bedding strata. When the height of the middle bench decreases from 4 m to 2 m, the tunnel deformation convergence decreases rapidly; When the length of the middle bench is less than 15 m, the deformation convergence of the tunnel decreases gradually with the increase of the length of the middle bench. When the middle bench length is greater than 15 m, the tunnel deformation convergence tends to be stable, and the tunnel deformation convergence is about 21 cm. The height of the middle bench in the bedding unsymmetrical loading section of Ganzhuang tunnel should be set at about 2 m, and the length of the middle bench should be controlled at more than 15 m. Field monitoring data show that this construction control technology has achieved good deformation control effect in Ganzhuang tunnel.
YU Guoliang1 LOU Yili2,
3 WU Guopeng1 SHI Chenghua2,
3 ZHENG Keyue2 etc
.Study on Deformation Control Technology for Unsymmetrically Loaded
Tunnels in Bedding Strata under High Geo-stress[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(5): 237-245
2022, Vol. 59 