Study on the Segment Damage Mechanism of Curved Shield Tunnels during Construction Stage

Objective Damage to shield tunnel segments will cause water seepage in the tunnel, affecting the structural bearing capacity and endanger the operational safety. Therefore, it is necessary to study the mechanism of segment structure damage. Method Through investigation and statistics, the occurrence law and influencing factors of segment diseases are obtained. ABAQUS software is used to conduct a numerical analysis on the force characteristics of segment detail structure, circumferential bolts, longitudinal bolts and concave-convex tenons under different jack horizontal thrusts. Result & Conclusion The incidence of segment damage increases gradually from vault to hance and then to arch bottom, and the incidence of damage in arch bottom area is the highest. The segment damage is closely related to the thrust value of the jack partitions. Numerical simulation results show that with the increase of the total thrust value, the maximum principal stress value of the bolt decreases gradually, while the value at the concave-convex tenon increases rapidly. The greater the thrust, the smaller the longitudinal bolt stress value. When the thrust is too large, the longitudinal bolt tensile stress tends to 0, the segment shrinks longitudinally, and the pressure on the segment increases sharply.