Abstract:During the shield tunneling with small curvature radius, due to the role of jack thrust, the segments will shift and stagger, which will lead to the safety accidents. In order to effectively solve the adverse impact of jack thrust on the segment during the construction of shield tunnel with small curvature radius, the tunneling mode of double-mode shield tunneling machine is analyzed. The calculation model of the thrust of the auxiliary oil cylinder jack in the shield tunneling process for the shield tunnel is established. And the model is applied in the engineering practice. The jack thrust is calculated and analyzed. The relevant measures to reduce or avoid the adverse effects of the jack thrust on the segment are proposed. The results show that during the construction of double-mode shield machine, the value of the thrust of the auxiliary oil cylinder jack in the different construction sections is different, and the thrust value should be determined according to the actual situation of the project. During the construction of single-mode shield machine, the thrust of the auxiliary oil cylinder jack increases with the increase of penetration, and the increasing rate gradually shows a decreasing trend. It is proposed to control and reduce the adverse impact of the jack thrust on the segment from the construction correction, segment assembly control, reasonable selection of tunneling parameters, shield machine attitude control, shield machine thrust control, setting of tunnel longitudinal stiffness and segment quality so as to ensure the safety of shield construction and provide the theoretical guidance and reference for the construction of similar projects.
