Abstract:
Adjacent construction of more than two tunnels will cause force changes of both existing and new tun? nels, and it′ s necessary to consider optimization issues of construction method, procedure, countermeasures and so on. Based on the construction of the shield-driven tunnel approaching the large-section mined tunnel of Changsha metro line 3, the numerical simulation and model test methods were adopted to study the effect of shield-driven tunnelling on adjacent mined tunnel in argillaceous siltstone stratum, and a concept of influence zoning was proposed in light of the criterion of ground surface settlement. Research results show that increase of corresponding surface settlement and additional displacement of existing mined tunnel are mainly caused during the process of shield driving which starts from 1 time tunnel diameter away from the studied section and finishes at completion of segment erection at the studied section ; in terms of the effect on the mined tunnel, vertical additional deformation is of the main form and it presents as overall tunnel heaving, the closer the existing tunnel structure to the shield-driven tunnel, the greater the influence; regarding the influence on internal force, it is manifested in uneven change of internal force of the existing mined tunnel structure, the existing tunnel structure near the shield-driven tunnel is more compressed and it is liable to occur tensile failure at the side far away from the shield-driven tunnel.