scholarly journals Spatiotemporal Deformation of Existing Pipeline Due to New Shield Tunnelling Parallel Beneath Considering Construction Process

2022 ◽  
Vol 12 (1) ◽  
pp. 500
Author(s):  
Xiang Liu ◽  
Annan Jiang ◽  
Qian Fang ◽  
Yousheng Wan ◽  
Jianye Li ◽  
...  
Keyword(s):  
Shield Tunnel ◽  
Support Pressure ◽  
Construction Process ◽  
Longitudinal Deformation ◽  
Deformation Control ◽  
Spatiotemporal Characteristic ◽  
Shield Tunnelling ◽  
Grouting Reinforcement ◽  
Ground Volume Loss ◽  
Parametric Analyses

In this paper, we study the effects of the shield tunnel construction on the deformation of an existing pipeline parallel to and above the new shield tunnel. We propose an analytical solution to predict the spatiotemporal deformation of the existing pipeline and consider different force patterns of the shield tunnelling, i.e., ground volume loss, support pressure, frictional force, and torsional force. The proposed method is validated by the monitoring data of Subway Line 3 of Nanchang and provides a reasonable estimation of the pipeline’s deformation. The parametric analyses are performed to study the influences on the pipeline’s deformation. The main advantage of our paper is that the spatiotemporal characteristics of the existing pipeline’s deformation are analysed, providing longitudinal deformation curve (LDC), deformation development curve (DDC), and grouting reinforcement curve (GRC). Compared with the perpendicular undercrossing project, both LDC and DDC have the same profiles and maximum values and move forward as a whole with the shield tunnel advance. Thus, the spatiotemporal deformation of the overall pipeline can be extrapolated from the deformation of two known points on the pipeline. The spatiotemporal characteristic curves combined with LDC, DDC, and GRC can suggest feasible, effective, and economical construction and grouting schemes to control the pipeline’s deformation after the deformation control standards have been determined.

scholarly journals Pore Water Pressure Responses in Sand Stratum during Shield Tunnelling: A Case Study

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yu Liang ◽  
Yufei Xiao ◽  
Yuexiang Lin
Keyword(s):  
Pore Water ◽  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Fine Sand ◽  
Element Model ◽  
Shield Tunnel ◽  
Support Pressure ◽  
Shield Tunnelling ◽  
Sand Stratum

When shield tunnelling is in a water-rich sand stratum with poor bearing capacity, instability is easily generated, and even ground collapses may occur. The variation of pore water pressure in a water-rich sand stratum during shield tunnelling was analyzed based on a large-scale cross-river shield tunnel in China, which was also investigated by a three-dimensional fluid-solid coupling finite element model. The results show that the influence range of the pore water pressure in front of the excavation face is approximately 2.0 times the excavation diameter and 1.5 times on both sides of the shield. The tunnelling steps would cause obvious variation in the pore water pressure and lead to great disturbance to the surrounding fine sand stratum. The quality of filter cake and the set of support pressure imposes an important impact on the nonlinear variation in the pore pressure, which could cause great disturbance to the stratum. To ensure the safety of the subsequent tunnelling in the fine sand layer, effective treatment should be taken.

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.

Surface Settlement and Influence on Xi’an City Wall due to Xi’an Subway Line 2 Tunnel Construction

2011 ◽  
Vol 374-377 ◽  
pp. 2326-2332
Author(s):  
Jun Lian Li ◽  
Jian Guo Zheng ◽  
Yang Ping Yao
Keyword(s):  
Surface Settlement ◽  
Shield Tunnel ◽  
Tunnel Construction ◽  
The South ◽  
Protective Measures ◽  
City Wall ◽  
Calculation Results ◽  
Settlement Ratio ◽  
Grouting Reinforcement ◽  
Xi’An City

This paper refers the case project of the Xi'an Subway Line 2 tunneling through the South Gate area of the Xi'an City Wall, has researched the surface settlement due to tunnel construction, and simulated the whole shield tunnel by using Flac3D numerical analysis. This paper has obtained the law of surface settlement and the influence on the City Wall in the tunnel construction by analyzing the calculation results, and simulated the effects of three protective measures which will be used in the South Gate area. The results showed that the surface settlement ratio after the piles and chemical grouting reinforcement was lower by about 25% than no reinforcement. The monitoring data showed that the result of model calculation was reasonable, and the protective measures in Condition 3 are feasible and effective.

Prediction of Shield Tunnelling-Induced Ground Settlement Considering Soil-Water Coupled and around Soil Disturbance Damage

2010 ◽  
Vol 168-170 ◽  
pp. 357-364
Author(s):  
Ji Feng Liu ◽  
Bo Liu ◽  
Hui Zhi Zhang
Keyword(s):  
Numerical Simulation ◽  
Soil Water ◽  
Ground Surface ◽  
Soil Disturbance ◽  
Surface Settlement ◽  
Shield Tunnel ◽  
Tunnel Construction ◽  
Ground Settlement ◽  
Ground Surface Settlement ◽  
Shield Tunnelling

to evaluate the influence of soil-water coupled and shield tunnel construction induced around soil disturbance damage on ground surface settlement, the process of shield tunnel construction induced around soil disturbance is analyzed, the FLAC3D numerical simulation are carried out, and a newly-modified tunnelling-induced ground settlement calculation method based on disturbance degree of around soil and soil-water coupled is presented, and these methods are applied in case of Beijing Metro 10thLine. It is indicated that considering the influence of the shield tunnelling-induced around soil disturbance damage, and soil-water coupled induced soil properties weakening and the excess pore water pressure dissipating induced soil consolidation to the ground surface settlement are necessary, the calculating result of the newly-modified surface settlement prediction method, and the result FLAC3D numerical simulation all agree well with in-site observed data of Beijing Metro 10th Line.

Research and Development of System of Shield Tunnelling to Adjacent Buildings

2011 ◽  
Vol 261-263 ◽  
pp. 1049-1053
Author(s):  
Zhi Ding ◽  
Guo Bao Ge ◽  
Xin Jiang Wei ◽  
Jie Hong
Keyword(s):  
Shield Tunnel ◽  
Tunnel Construction ◽  
Building Structure ◽  
Ground Settlement ◽  
Adjacent Buildings ◽  
Data Binding ◽  
Different Types ◽  
Shield Tunnelling ◽  
Analysis System ◽  
Extent Of Damage

Considering different types of building structure and foundation, the system refers to acceptable ground settlement and acceptable soil loss ratio was established by establishing the control of building’s bending and deformation. The system which adopted Delphi dynamic data binding technology and used Access as database was developed by Delphi7.0 visual tools. The system which named "Analysis system about shield tunnel construction to adjacent buildings" is developed to judge the extent of damage of buildings influenced by adjacent shield tunnel construction.

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.

Analysis on Damage Cause of Shield Tunnel Segments during Construction

2012 ◽  
Vol 594-597 ◽  
pp. 1308-1313 ◽  
Author(s):  
Jun Hong Zhou ◽  
Di Wu ◽  
Shun Hua Zhou ◽  
Yi Xiao Cui
Keyword(s):  
Thrust Force ◽  
Shield Tunnel ◽  
Tunnel Construction ◽  
Construction Process ◽  
Damage Characteristics ◽  
Discontinuous Model

Abstract. Due to the complexity of shield tunnel construction process, some segments may be damaged. To obtain the cause of segmental damage, stress acting on segments is needed to be analyzed. In this paper, the damage characteristics of a shield tunnel segments were summarized firstly, then a 3D discontinuous model considering of shield tunnel segments and bolts was established to analyze the stress characteristics of segments during construction. The study has manifested that squeezing of segmental bump tenon, thrust force and its obliquity, uneven jack thrust are the main causes of segmental damage during the shield tunnel construction.

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