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Construction Techniques and Safety Analysis for a Deep Vertical Shaft and Vertical Shaft Shifting to Main Tunnel
(1 Hunan Provincial Key Laboratory of Geotechnical Engineering for Stability Control and Health Monitoring, School of Civil Engineering, Hunan University of Science and Technology, Xiangtan 411201; 2 School of Civil Engineering, Central South University,Changsha 410075; 3 College of Civil Engineering and Architecture, Guangxi University, Nanning 530004)
Abstract Considering the geological conditions and problems encountered in construction, the vertical shaft con? struction technique and construction program for vertical shaft shifting to the main tunnel are proposed based on the No.2 shaft of the Liuyang river tunnel, for which the top-down construction method is adopted for the vertical shaft;an enclosed circular horizontal force- bearing structure with great stiffness is formed by the retaining piles, shotcrete-bolt support and lining; and the construction of the vertical shaft shifting to the main tunnel and the vertical shaft construction at the bottom are performed simultaneously, solving the problem of a high operating platform during main tunnel excavation. A simulation model is established, and the safety of this construction method is analyzed considering the onsite monitoring results. Implementation result shows that the ground displacement, the force on initial support and secondary lining of the vertical shaft and the force on the initial support of the main tunnel meet the safety requirements, and the large bending moments of the initial support of the main tunnel are mainly concentrated near the tunnel arch spring during the construction of the vertical shaft shifting to the main tunnel, with the maximum bending moment increasing with excavation.
Abstract：
Considering the geological conditions and problems encountered in construction, the vertical shaft con? struction technique and construction program for vertical shaft shifting to the main tunnel are proposed based on the No.2 shaft of the Liuyang river tunnel, for which the top-down construction method is adopted for the vertical shaft;an enclosed circular horizontal force- bearing structure with great stiffness is formed by the retaining piles, shotcrete-bolt support and lining; and the construction of the vertical shaft shifting to the main tunnel and the vertical shaft construction at the bottom are performed simultaneously, solving the problem of a high operating platform during main tunnel excavation. A simulation model is established, and the safety of this construction method is analyzed considering the onsite monitoring results. Implementation result shows that the ground displacement, the force on initial support and secondary lining of the vertical shaft and the force on the initial support of the main tunnel meet the safety requirements, and the large bending moments of the initial support of the main tunnel are mainly concentrated near the tunnel arch spring during the construction of the vertical shaft shifting to the main tunnel, with the maximum bending moment increasing with excavation.
.Construction Techniques and Safety Analysis for a Deep Vertical Shaft and Vertical Shaft Shifting to Main Tunnel[J] MODERN TUNNELLING TECHNOLOGY, 2018,V55(2): 164-173
2018, Vol. 55 