SEGMENT CRACKS AND ALIGNMENT ISSUES FOR TUNNELING CONSTRUCTION

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Arulampalam Paul Suyanthiran
Keyword(s):  
Tunnel Boring Machine ◽  
Shield Tunnel ◽  
Proper Selection ◽  
Tunnel Boring ◽  
Twin Tunnel ◽  
Shield Tunnelling ◽  
Tunnel Alignment ◽  
Selection Of ◽  
Left Lead

This study describes the causes of shield tunnel segment cracks and alignment issues during shield tunnelling. The study was conducted in Down Town Line 3 (DTL3) contracts 926 and 927 twin tunnel projects in Singapore. It is revealed that these issues arose when Tunnel Boring Machine (TBM) shoving on curve alignment though TBM is designed with articulation, which allows the machines to handle tight curves with ease. The study focused on how construction methodology affects the quality of tunnelling in terms of alignment and segment cracks. It was found that the clearance between the tail shield and tunnel lining was not maintained during mining. As a result, the tail shield exerts stress on the segments and causes cracks. In addition, the tunnel alignment deviated from pre-designed alignment, which directly affects the safety and durability of the shield tunnel. This study concludes that a proper selection of ring type “right lead” or “left lead” and the appropriate key selection, along with the skill of the workers, significantly solve segment cracks and alignment issues.

scholarly journals Numerical Simulation of EPB Shield Tunnelling with TBM Operational Condition Control Using Coupled DEM–FDM

2021 ◽  
Vol 11 (6) ◽  
pp. 2551
Author(s):  
Hyobum Lee ◽  
Hangseok Choi ◽  
Soon-Wook Choi ◽  
Soo-Ho Chang ◽  
Tae-Ho Kang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Large Scale ◽  
Tunnel Boring Machine ◽  
Chamber Pressure ◽  
Screw Conveyor ◽  
Shield Tunnel ◽  
Pressure Balance ◽  
Operational Conditions ◽  
Shield Tunnelling ◽  
Epb Shield

This study demonstrates a three-dimensional numerical simulation of earth pressure balance (EPB) shield tunnelling using a coupled discrete element method (DEM) and a finite difference method (FDM). The analysis adopted the actual size of a spoke-type EPB shield tunnel boring machine (TBM) consisting of a cutter head with cutting tools, working chamber, screw conveyor, and shield. For the coupled model to reproduce the in situ ground condition, the ground formation was generated partially using the DEM (for the limited domain influenced by excavation), with the rest of the domain being composed of FDM grids. In the DEM domain, contact parameters of particles were calibrated via a series of large-scale triaxial test analyses. The model simulated tunnelling as the TBM operational conditions were controlled. The penetration rate and the rotational speed of the screw conveyor were automatically adjusted as the TBM advanced to prevent the generation of excessive or insufficient torque, thrust force, or chamber pressure. Accordingly, these parameters were maintained consistently around their set operational ranges during excavation. The simulation results show that the proposed numerical model based on DEM–FDM coupling could reasonably simulate EPB driving while considering the TBM operational conditions.

In-plane dynamic response of a hydraulic pipe subjected to random vibration

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wei Qu ◽  
Huailiang Zhang ◽  
Wei Li ◽  
Ling Peng ◽  
Wenqian Sun
Keyword(s):  
Random Vibration ◽  
Tunnel Boring Machine ◽  
Transmission Efficiency ◽  
Hydraulic Systems ◽  
Analysis Method ◽  
The Finite Element Method ◽  
Characteristic Analysis ◽  
Content Type ◽  
Tunnel Boring ◽  
Selection Of

Purpose To improve the transmission efficiency and reduce the damage to pipes in the hydraulic systems of tunnel boring machine subjected to random vibration, this paper aims to propose a novel dynamic characteristic analysis method that considers random vibration. Design/methodology/approach A fluid-structure interaction motion equation of the pipe is established by using Hamilton’s principle. The finite element method and discrete analysis method of random vibration are used to construct a model of the dynamic behavior of the pipe. Findings The influences of fluid parameters and external excitation parameters on the dynamic characteristics of pipes are analyzed. The experimental results are found to be in good agreement with the simulation results, which demonstrates that the proposed analytical method can provide a theoretical reference for the design and selection of hydraulic pipes subjected to random vibration. Originality/value The proposed method can be regarded as a future calculation method for pipes subjected to random vibration, and the transmission efficiency of the pipe can be improved.

scholarly journals 3D MODELLING OF TUNNEL EXCAVATION USING PRESSURIZED TUNNEL BORING MACHINE IN OVERCONSOLIDATED SOILS

2013 ◽  
Vol 35 (2) ◽  
pp. 3-17 ◽  
Author(s):  
Rafik Demagh ◽  
Fabrice Emeriault
Keyword(s):  
Numerical Simulation ◽  
Urban Areas ◽  
Three Dimensional ◽  
Ground Surface ◽  
Tunnel Boring Machine ◽  
Confining Pressure ◽  
Soil Mass ◽  
Shield Tunnel ◽  
Tunnel Boring ◽  
Boring Machines

Abstract The construction of shallow tunnels in urban areas requires a prior assessment of their effects on the existing structures. In the case of shield tunnel boring machines (TBM), the various construction stages carried out constitute a highly three-dimensional problem of soil/structure interaction and are not easy to represent in a complete numerical simulation. Consequently, the tunnelling- induced soil movements are quite difficult to evaluate. A 3D simulation procedure, using a finite differences code, namely FLAC3D, taking into account, in an explicit manner, the main sources of movements in the soil mass is proposed in this paper. It is illustrated by the particular case of Toulouse Subway Line B for which experimental data are available and where the soil is saturated and highly overconsolidated. A comparison made between the numerical simulation results and the insitu measurements shows that the 3D procedure of simulation proposed is relevant, in particular regarding the adopted representation of the different operations performed by the tunnel boring machine (excavation, confining pressure, shield advancement, installation of the tunnel lining, grouting of the annular void, etc). Furthermore, a parametric study enabled a better understanding of the singular behaviour origin observed on the ground surface and within the solid soil mass, till now not mentioned in the literature.

Dynamic Modeling and Analysis of Shield TBM Cutterhead Driving System

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Xian Hong Li ◽  
Hai Bin Yu ◽  
Ming Zhe Yuan ◽  
Jin Wang ◽  
Yuan Yin
Keyword(s):  
Dynamic Model ◽  
Tunnel Boring Machine ◽  
Transmission Error ◽  
Shield Tunnel ◽  
Modeling And Analysis ◽  
Driving System ◽  
Output State ◽  
Tunnel Boring ◽  
Gear Backlash ◽  
Multiple Input

In this paper, a generalized nonlinear time-varying dynamic model is established for the cutterhead driving system of a shield tunnel boring machine. A nonlinear multiple input and multiple output state-space dynamic model is also proposed. The dynamic model is simulated to analyze the driving system and the effects of system parameters such as gear backlash and transmission error, larger gear inertia, and load torque on the dynamic response of driving system are investigated as well. A preliminary approach is proposed to restrain speed oscillation and reduce steady-state speed ripple. Through modeling and studying the dynamic model, we refine some important issues that should be given closer attention.

scholarly journals Use of saturation diving technique for tunnel boring machine cutterhead intervention in the Tuen Mun–Chek Lap Kok Link Sub-sea Tunnel Project, Hong Kong

2021 ◽  
Vol 28 (1) ◽  
pp. 31-38
Author(s):  
A W Y Chan ◽  
Charles H C Yeung ◽  
A J Westmoreland ◽  
S W Fok ◽  
Conrad C W Ng ◽  
...  
Keyword(s):  
Hong Kong ◽  
Cutting Tools ◽  
Tunnel Boring Machine ◽  
Tunnel Boring ◽  
Tunnel Section ◽  
Decomposed Granite ◽  
Boring Machines ◽  
Mixed Ground ◽  
Tunnel Alignment ◽  
Ground Condition

The entire Tuen Mun–Chek Lap Kok Link (TM-CLKL) was commissioned on 27 December 2020 and it comprises a 9km-long dual 2-lane carriageway between Tuen Mun and North Lantau, Hong Kong. Construction of the 5km-long sub-sea tunnels was carried out by two 14m diameter Tunnel Boring Machines (TBMs). The tunnel alignment for the TM-CLKL sub-sea tunnel section is in mixed ground condition with the first 500 m in mixed geology of slightly to moderately decomposed granite and completely decomposed granite (CDG), followed by soft ground condition with CDG, alluvial sand, alluvial clay and marine deposit. This mixed ground geology requires regular TBM cutterhead interventions to change the worn-out cutting tools during the tunnelling operation. As the tunnel alignment is up to 55 m below the sea level with the deepest seabed level at -21 mPD, in order to maintain the cutting face stability during the intervention, the intervention pressure could be up to 6 bars. This paper describes different techniques used for TBM interventions under the sea such as trimix bounce mode and saturation mode that appears first time in Hong Kong under a high hyperbaric pressure to change the worn-out cutting tools at the TBM cutterhead.

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