Limit support pressure on tunnel face at different construction line slopes by slip line method

2020 ◽  
Vol 106 ◽  
pp. 103619
Author(s):  
Weiping Liu ◽  
Shaofeng Wan ◽  
Mingfu Fu
Keyword(s):  
Slip Line ◽  
Support Pressure ◽  
Tunnel Face ◽  
Line Method

scholarly journals Face Stability Analysis of Shield Tunnel Using Slip Line Method

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Weiping Liu ◽  
Shaofeng Wan ◽  
Xinqiang Song ◽  
Mingfu Fu ◽  
Lina Hu
Keyword(s):  
Stability Analysis ◽  
Slip Line ◽  
Yield Criterion ◽  
Limit Equilibrium ◽  
Shield Tunnel ◽  
Support Pressure ◽  
Tunnel Face ◽  
Face Stability ◽  
Line Method ◽  
The Stability

The sufficient support pressure is essential to guarantee the safe construction of shield tunnel. Thus, it is necessary to analyze the stability and assess the limit support pressure of the tunnel face. The main methods for face stability analysis mostly focused on finite element method, limit equilibrium method, and numerical simulation method. In this paper, the slip line method is applied to analyze the stability of the tunnel face. The soil is supposed as ideal isotropic, homogeneous, and incompressible continuous material, which obeys the Mohr–Coulomb yield criterion. A mathematical model of the limit equilibrium boundary value problem is established. The slip line method is used to solve the slip line field and stress field of the soil behind the tunnel face. Limit support pressure and failure mechanism of the tunnel face are then obtained. In addition, comparisons between the results of this study and those of existing approach are performed, and the influence factors are also discussed. The results show that the slip line method is proven to be reliable for the evaluation of limit support pressure of the tunnel face stability.

scholarly journals Face Stability Analysis of Shield Tunnels in Homogeneous Soil Overlaid by Multilayered Cohesive-Frictional Soils

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Kaihang Han ◽  
Chengping Zhang ◽  
Wei Li ◽  
Caixia Guo
Keyword(s):  
Failure Mechanism ◽  
Shear Failure ◽  
Three Dimensional ◽  
Earth Pressure ◽  
Support Pressure ◽  
Tunnel Face ◽  
Arch Effect ◽  
Theory Approximation ◽  
Homogeneous Soil ◽  
Frictional Soils

In order to better interpret failure features of the failure of soil in front of tunnel face, a new three-dimensional failure mechanism is proposed to analyze the limit support pressure of the tunnel face in multilayered cohesive-frictional soils. The new failure mechanism is composed of two truncated cones that represent the shear failure band and a distributed force acting on the truncated cones that represents the pressure arch effect. By introducing the concept of Terzaghi earth pressure theory, approximation of limit support pressures is calculated using the limit analysis methods. Then the limit support pressures obtained from the new failure mechanism and the existing approaches are compared, which show that the results obtained from the new mechanism in this paper provide relatively satisfactory results.

scholarly journals Investigation on the Influence Caused by Shield Tunneling: WSN Monitoring and Numerical Simulation

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hao Liu ◽  
Jinjiang Shi ◽  
Jiasen Li ◽  
Chao Liu
Keyword(s):  
Signal Transmission ◽  
Monitoring Data ◽  
Shield Tunnel ◽  
Support Pressure ◽  
Shield Tunneling ◽  
Tunnel Face ◽  
Wireless Monitoring ◽  
Mems Sensor ◽  
Grouting Pressure ◽  
Transmission Test

Traditional monitoring techniques are faced with the problems of low acquisition frequency and easy to be affected by the construction environment during the shield tunneling, which cannot meet the actual needs of timeliness monitoring of surrounding environmental impact on shield tunnel construction. Based on this actual demand, a wireless sensor network (WSN) system was used to monitor the response of shield tunnel segments and surrounding buildings during the shield tunneling in this study. According to the result of the signal transmission test, an optimization scheme of microelectromechanical system (MEMS) sensor layout is designed to improve the monitoring efficiency of the WSN system. Through the comparative analysis of WSN system monitoring data and traditional monitoring data, it is found that, with the increasing distance between the monitoring section and the tunnel face, the convergence value of tunnel lining clearance gradually tends to be stable, and the wireless monitoring results of transverse clearance convergence of the tunnel in this section are consistent with the overall deformation trend of the convergence gauge monitoring results. This study also simulated the shield tunneling adjacent buildings using a nonlinear finite element method. A parameter sensitivity analysis of the support pressure of the excavation face and the grouting pressure at the tail of the shield is carried out. The results show that the surface settlement can be reduced by properly increasing the grouting pressure and the support pressure of the excavation face. Moreover, increasing the support pressure of the excavation face has a better inhibition effect on the settlement of the surface soil than increasing the grouting pressure.

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