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Study on the Effect on Deformation of the Surrounding Rock Induced by DeepBuried Tunnelling under Hard Rock Combination Conditions
(1 Northwest Research Institute Co.,Ltd of C.R.E.C, Lanzhou 730070; 2 China Railway Landslide Engineering Laboratory, Lanzhou 730070; 3 China Academy of Railway Sciences Corporation Limited, Beijing 100081; 4 Engineering Laboratory of Western Environmental Geotechnology and Site Remediation Technology, Lanzhou 730070)
Abstract When a tunnel is located in deep-buried bedding hard rock structures, the rock deformation and failure caused by the stress redistribution have a certain level of particularities due to their stratification characteristics and structural forms. This paper takes the Huangcao tunnel on a certain high-speed railway as the engineering case,studies the distribution of the secondary stress field in the surrounding rock affected by excavation through numerical calculation, mainly taking into consideration the influence of hard rock bedding and joints, and evaluates the deformation of the surrounding rock accordingly. The results show that (1) when considering the interaction of bedding and conjugate joints in deep-buried tunnels, the primary and secondary deformation displacements are not obvious in terms of the direction, while the circumferential displacement is featured by asymmetric distribution; (2) the greater is the tunnel depth, the greater the deformation displacement of the tunnel walls will be under excavation conditions, and the maximum deformation and contour range are developed in the direction of the vertical plane; (3) the presence of conjugate joints greatly reduces the asymmetric deformation features of rocks in bedding tunnels; (4) under the impact of horizontal tectonic stress fields, larger deformation displacement is generated in the tunnel walls in the direction of the maximum horizontal principal stress.
Abstract：
When a tunnel is located in deep-buried bedding hard rock structures, the rock deformation and failure caused by the stress redistribution have a certain level of particularities due to their stratification characteristics and structural forms. This paper takes the Huangcao tunnel on a certain high-speed railway as the engineering case,studies the distribution of the secondary stress field in the surrounding rock affected by excavation through numerical calculation, mainly taking into consideration the influence of hard rock bedding and joints, and evaluates the deformation of the surrounding rock accordingly. The results show that (1) when considering the interaction of bedding and conjugate joints in deep-buried tunnels, the primary and secondary deformation displacements are not obvious in terms of the direction, while the circumferential displacement is featured by asymmetric distribution; (2) the greater is the tunnel depth, the greater the deformation displacement of the tunnel walls will be under excavation conditions, and the maximum deformation and contour range are developed in the direction of the vertical plane; (3) the presence of conjugate joints greatly reduces the asymmetric deformation features of rocks in bedding tunnels; (4) under the impact of horizontal tectonic stress fields, larger deformation displacement is generated in the tunnel walls in the direction of the maximum horizontal principal stress.
CHANG Gang1,
2 PAI Lifang3,
4 PANG Weijun1 etc
.Study on the Effect on Deformation of the Surrounding Rock Induced by DeepBuried Tunnelling under Hard Rock Combination Conditions[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(5): 73-77
2021, Vol. 58 