Anti-seismic Effect of the Shock Absorption Layer in Tunnel

Abstract

Tunnels play a vital role in the transportation industry and many other industries. In fact, a tunnel damaged by an earthquake has a serious impact on traffic. Therefore, tunnel destruction induced by earthquakes have been paid more and more attentions. In this study, vibration theory is used for a simplified mechanical model of a tunnel lining system composed of a primary lining, a layer of shock absorption and a second lining. The parameters, such as the mass ratio, the damping ratio and the stiffness ratio of the vibration equation, are simplified correspondingly and solved in the complex domain, resulting in a simplified transfer coefficient. At the same time, numerical simulation and analysis are also carried out. The results show that: 1) The shock absorption layer with a low stiffness ratio has a good damping effect under low-frequency vibration, while under high-frequency vibration, the stiffness ratio has less influence on the transmission coefficient. 2) By analyzing the results of the theoretical calculation and numerical simulation, the tunnel structure under high-frequency vibration can be seen, and when the shock absorption layer stiffness is in close proximity to the second lining stiffness, the deformation and stress of the tunnel lining are the smallest. In general, the application of double-lining in strong earthquake zones can reduce the vibration of the tunnel lining and protect the tunnel from damage.

Prediction method of shield tunneling parameters in pebble stratum formed by weathered granite and quartzite

“…Therefore, how to accurately predict and control the tunneling parameters has always been the research focus in the field of shield tunnel construction technology (Pan et al, 2022). At present, many scholars have studied the variation laws and theoretical calculations of cutter head torque, shield thrust, grouting pressure, tunneling speed and other parameters under different geological conditions during EPB shield tunneling, and established mathematical and physical models to predict tunneling parameters according to Hooke's law (Jie et al, 2017;Wei et al, 2017;Yang et al, 2017;Zhao et al, 2017;Boukhari, 2020;Cao et al, 2020;Gao et al, 2020;Al-Habahbeh, 2022;Lu et al, 2022;Lyu et al, 2022). Although these models can reflect the analytical relationship between tunneling parameters, shield tunneling is a complex and changing process, and the stratum it crosses is actually a non-uniform and discontinuous non-linear elastomer.…”