scholarly journals Analysis of Structural Response of Subway Shield Tunnel Lining under the Influence of Cavities

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Yufeng Shi ◽  
Zhaoyang Chen ◽  
Duqiang Wei ◽  
Tao Zhang ◽  
Xuming Zhou ◽  
...  
Keyword(s):  
Structural Response ◽  
Bending Moment ◽  
Tunnel Lining ◽  
Structural Safety ◽  
Shield Tunnel ◽  
Cavity Depth ◽  
Stiffness Reduction ◽  
Lining Structure ◽  
Reduction Effect ◽  
Single Cavity

The existence of cavities behind the shield tunnel lining can cause cracking, broken pieces, water leakage, and other problems, which reduces the durability and safety of the shield tunnel segment structure. In order to clarify the mechanism of cavity damage, a more systematic study of the effects of cavities on the shield tunnel lining structure from the angle, depth, and the number of cavities is carried out using model tests and numerical simulations without considering the effects of the stiffness reduction effect at the tunnel segment joints and groundwater seepage in this paper. The findings show that the bending moment value and the cavity angle value are approximately linear with the increase of single cavity angle, and the bending moment at the vault arch is reversed when the angle of the cavity behind the arch is greater than 30°. With the increase of single cavity depth, the axial force and bending moment at the cavity increase, and the distribution of bending moment remains unchanged, and the bending moment tends to be stable and unchanged beyond a certain depth. With the increase of single cavity angle and depth, the structural safety coefficient of the segment decreases, and the degree of influence is angle value > depth value. The existence of multiple cavities intensifies the influence of each cavity on the segment, especially when there are cavities behind the top and bottom of the vault; the bending moment value of the top of the vault increases by 22.53% compared with that of the single cavity condition.

scholarly journals Synthesis of numerical methods for the design of segmental tunnel lining

2019 ◽  
Vol 295 ◽  
pp. 03008
Author(s):  
Rim Trad ◽  
Hussein Mroueh ◽  
Hanbing Bian ◽  
Fabrice Cormery
Keyword(s):  
Numerical Study ◽  
Direct Method ◽  
Bending Moment ◽  
Experimental Methods ◽  
Tunnel Lining ◽  
Practical Case ◽  
Lining Structure ◽  
Water Conveyance ◽  
Internal Forces ◽  
Water Conveyance Tunnel

This paper presents a numerical study that aims to compare the behavior of the segmental tunnel lining using the direct, indirect and experimental methods. This model is based on a practical case applied in university of Tongji: a project of water conveyance tunnel. A reduction in the bending moment and increasing of the displacement in the tunnel lining is showed in numerical results, when taking into account the effect of the joints. It has been shown that the number of joints in the tunnel-lining structure highly affects the results in terms internal forces and displacements. Furthermore, the internal forces obtained by the continuous method are high compared to the other methods when the effects on segmental joints on tunnel lining behaviour are usually considered. Additionally, the bending moment of the direct method with behaviour of rotation spring linear and experimental method is comparable.

scholarly journals Performance Investigation of Tunnel Lining with Cavities around Surrounding Rocks

2020 ◽  
Vol 2020 ◽  
pp. 1-5 ◽  
Author(s):  
Jiajia Li ◽  
Yong Fang ◽  
Cheng Liu ◽  
Yongxing Zhang ◽  
Weihua Lu
Keyword(s):  
Stress State ◽  
Numerical Investigation ◽  
Tunnel Lining ◽  
Cavity Size ◽  
Cavity Depth ◽  
Tunnel Stability ◽  
Severe Effect ◽  
Single Cavity ◽  
Cavity Width

This paper presents a systematical numerical investigation into the lining performance of a tunnel with cavities around surrounding rocks, focusing on the influences of cavity size and multicavity distribution. The study demonstrates that the cavities around surrounding rocks have much influence on tunnel stability and may induce damages in tunnel structures, in which cavity width has a more severe effect on the stress state of tunnel structures than cavity depth. Moreover, the numerical investigation also illustrates that the nonadjacent distribution of multicavities has more serious influence on tunnel structures than that from adjacent distribution of multicavities as well as that from a single cavity.

Effect of Time-Varying on Shield Tunnel Lining Structure

2014 ◽  
Vol 580-583 ◽  
pp. 987-990
Author(s):  
Feng Jun Liu ◽  
Jun Fang Chen
Keyword(s):  
Design Theory ◽  
Aging Effect ◽  
Tunnel Lining ◽  
Shield Tunnel ◽  
Time Varying ◽  
Bending Rigidity ◽  
Concrete Shrinkage ◽  
Lining Structure ◽  
Long Time ◽  
Internal Forces

In order to survey the time-varying effect on shield tunnel lining structure, rigidity reduce in the Homogeneous Ring Design Theory is introduced. There are three methods to evaluate the rigidity reduction caused by the aging effect. The first is the bending rigidity analysis method, which considers that the bending rigidity changes with the time-dependent stress and strain. The second is the method named the equivalent moment of inertia; the last is aging coefficient method. With the Homogeneous Ring Design Theory, the internal forces and displacement of the shield tunnel segment lining can be calculated. Based on the preliminary results, using the 1st method, the reduced rigidity and the long-time displacement at different instants of time can be calculated. It is found that the concrete shrinkage and creep effect can’t be ignored in the segment design. The survey is beneficial to monitor the deformation of tunnel lining, and the maintenance of the segments. It will make the tunnel work steadily and safely during the using period.

Coupled Numerical Analysis of Tunnel Excavation in Saturated Soft Clay under High Groundwater

2011 ◽  
Vol 368-373 ◽  
pp. 2533-2536
Author(s):  
Hua Yuan ◽  
Hai Tao Wan ◽  
Zhi Liang Zhao
Keyword(s):  
Soft Clay ◽  
Three Dimensional ◽  
Bending Moment ◽  
High Water ◽  
Shield Tunnel ◽  
Deep Soil ◽  
Tunnel Excavation ◽  
Axial Forces ◽  
Reduction Effect ◽  
Saturated Soft Clay

A coupled numerical simulation of a river-crossing shield tunnel excavation in saturated soft clay with high groundwater has been performed using a three-dimensional finite difference model, which takes into account variation of soil permeability with stress, anisotropy of permeability, reduction effect of joints on segment bending stiffness and the hardening process of synchronized grouting material. Groundwater seepage conditions around the tunnel, bending moment, axial forces and strength safety factor of tunnel segment as well as deep soil displacement during tunnel diving are investigated numerically. The analyses provide valuable information concerning the mechanical behavior of tunnel segment and hydrological field in soil around tunnel during advancing. The result also is benefited to control groundwater for river-crossing tunnel in soft clay under high water table.

Numerical Simulation on the Stress and Strain of Lining Structure with Double Shield Tunneling Construction

2012 ◽  
Vol 605-607 ◽  
pp. 2425-2429
Author(s):  
Feng Wang ◽  
Tie Jun Cui
Keyword(s):  
Ground Surface ◽  
Calculation Model ◽  
Tunnel Lining ◽  
Concrete Lining ◽  
Shield Tunnel ◽  
Tunnel Construction ◽  
Three Dimension ◽  
Shield Tunneling ◽  
Deformation Law ◽  
Lining Structure

This paper takes the Section 201 of shield construction engineering in Dalian Metro Line 2 as an example to analyze the deformation law of surrounding soil and the tunnel lining structure stress during shield tunnel construction. The shield tunnel construction is simulated dynamically by ADINA and the shield tunnel structure model of the concrete lining is established. This model is a three-dimension nonlinear finite element calculation model concerned with the grouting soil and original state soil. Taking the soil lithology in the upper layer and interact influences, we analyzed the dynamic process of shield construction, soil grouting and lining supporting and the stress distribution in difference reinforced concrete supporting segments and the ground settlement characteristics. Through numerical analysis method to study the deformation law of soil surrounding tunnel and the stress in tunnel lining, we get the results to compare with the results of Peck formula under the same condition. After generating the conclusions, we can provide several suggestions for shield tunneling construction, lining segment design and control of the ground surface settlement during the construction.

scholarly journals Numerical Investigation on Crack Propagation and Fatigue Life Estimation of Shield Lining under Train Vibration Load

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Long-gang Tian ◽  
Zi-ling Cheng ◽  
Zhi-qiang Hu
Keyword(s):  
Fatigue Life ◽  
Crack Propagation ◽  
Tunnel Lining ◽  
Shield Tunnel ◽  
Vibration Load ◽  
Life Estimation ◽  
Fatigue Life Estimation ◽  
Lining Structure ◽  
Train Speed ◽  
Train Vibration

Dynamic loads such as the train vibration load usually act on the shield tunnel lining in the long term, which could make the initial flaws in shield segment propagate and gradually weaken the robustness of the tunnel structure. In this paper, a three-dimensional numerical model of shield tunnel lining structure with the initial defect is built to study its dynamic reaction and fatigue crack propagation under the train vibration load. Furthermore, the damage to intact shield segment caused by train vibration load is studied by employing the rain-flow counting method and the Miner damage theory, and a rational fatigue life estimation for the concrete shield tunnel lining is finally made. Results show that crack propagation is influenced by both the train speed and train axle, the higher the train speed, the longer the final crack, and train axle has a larger influence than train speed on the crack propagation in shield tunnel segment. The shield tunnel lining structure of Nanjing Metro Line 5 can meet the demand of working for a hundred years under the current working conditions.

Based on the Series System Initial Tunnel Lining Supporting System Reliability Analysis

2012 ◽  
Vol 446-449 ◽  
pp. 995-1001
Author(s):  
Si Yang Chen ◽  
Zhong Li ◽  
Yan Peng Zhu ◽  
Tian Yu Zhang ◽  
Hua Wen Ou
Keyword(s):  
System Reliability ◽  
Reliability Index ◽  
Interval Estimation ◽  
Bending Moment ◽  
Tunnel Lining ◽  
Series System ◽  
Tunnel Support ◽  
Law System ◽  
Lining Structure ◽  
Calculation Results

For the initial lining structure of tunnel , constructing an consider integrated safety factor function.Consider the initial shotcrete tunnel support structure as a series system, using the interval estimation of the "wide boundaries of law" system of tunnel lining structure analysis, on this basis to determine the system failure mode. Using the limit displacement under the condition of axial force and bending moment of the corresponding displacement and construction monitoring of displacement are analyzed, considering the material properties, geometry and random effects. Using the Monte Carlo finite element method, combined with a typical project example to tunnel structural system reliability index were calculated. The calculation results show that in the engineering example, tunnel lining structure in some local section of the reliability index is smaller, but the whole support system reliability indexes meet the design requirements, the whole tunnel lining structure in a safe state.

scholarly journals Optimization Study on Longitudinal Joints in Quasi-Rectangular Shield Tunnels

2021 ◽  
Vol 11 (2) ◽  
pp. 573
Author(s):  
Weixi Zhang ◽  
Wouter De Corte ◽  
Xian Liu ◽  
Luc Taerwe
Keyword(s):  
Bending Moment ◽  
Shield Tunnel ◽  
Second Stage ◽  
Crack Penetration ◽  
Optimization Study ◽  
Lining Structure ◽  
Negative Moment ◽  
New Type ◽  
Longitudinal Joints ◽  
Joint Section

There are large bending moments in quasi-rectangular shield tunnels due to their deviation from the circular shape, and as for other types of shield tunnels, the longitudinal joints are the most critical parts in the lining structure. A new type of joint with ductile iron joint panels (DIJPs) was installed in quasi-rectangular tunnels to solve these problems. The distance from the bolts to the segment’s inner surface was improved for better performance under specific bending moment types. Both tests and finite element modeling (FEM) simulations were conducted to investigate the effect of the bolt position improvements. The resistances to crack appearance increased by 33.6% and 18.0% for positive and negative moment cases, respectively. The resistances to crack penetration increased by 13.8% and 18.4% for positive and negative cases. From the FEM approach, it was found that the behavior of the joint under the design bending moment range can be divided into three stages, whereby the bolts are only active from the second stage on. The effects of other optimizing methods, such as enhancement of concrete properties and increase of bolt diameters and numbers, are explored. Through comparison, it is believed that optimizing the joint section to increase the lever arm between bolts and the compression zone can improve the joint behavior most effectively. This optimization direction is recommended when designing a shield tunnel joint with DIJPs.

Transverse Response of Underwater Shield Tunnel to Incident P Waves

2011 ◽  
Vol 90-93 ◽  
pp. 1602-1609
Author(s):  
Hong Wei Ma ◽  
Wen Hua Chen
Keyword(s):  
Seismic Response ◽  
Water Depth ◽  
Exact Analytical Solution ◽  
Incident Angle ◽  
Expansion Method ◽  
Tunnel Lining ◽  
Shield Tunnel ◽  
P Waves ◽  
Lining Structure ◽  
Underwater Tunnel

In this paper, the seismic response of underwater shield tunnel to incident P waves is investigated by using the Fourier-Bessel series expansion method. On the basis of the exact analytical solution, it is studied that the seismic response of the system which is made up of tunnel lining structure, underwater soil and water. The influence that water depth and buried depth of shield tunnel put on the seismic response of tunnel lining is given. The analytical result shows that the seismic response of tunnel lining unobvious varies with water depth change when incident P waves have a small incident angle, nevertheless, opposite conclusion appears when oblique incident P waves have a big incident angle. At a certain incident angle, the seismic response of tunnel increases with the increasing of the water depth; and the seismic response decreases with the increasing of the buried depth of underwater tunnel.

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