Theoretical Method of Chamber Pressure for EPB Shield Tunneling Under-Crossing Existing Metro Tunnels

2021 ◽  
Author(s):  
Hongpeng Lai ◽  
Tengteng Wang ◽  
Zuo Kang ◽  
Rui Chen ◽  
Qiuyang Hong
Keyword(s):  
Theoretical Method ◽  
Chamber Pressure ◽  
Shield Tunneling ◽  
Epb Shield

scholarly journals Phenomenon and Critical Conditions of Chamber Soil Sliming during EPB Shield Tunneling in Water-Rich Weathered Diorite: Case Study of Jinan Metro, China

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Lu Wang ◽  
Wei Zhu ◽  
Yongjin Qian ◽  
Chao Xu ◽  
Jiannan Hu ◽  
...  
Keyword(s):  
Pressure Chamber ◽  
Critical Conditions ◽  
Chamber Pressure ◽  
Water Volume ◽  
Seepage Water ◽  
Pressure Balance ◽  
Shield Tunneling ◽  
Rock Stratum ◽  
Effective Measure ◽  
Epb Shield

The sliming problem of chamber soil is caused by excessive groundwater seeping into the pressure chamber when an Earth pressure balance shield tunnels through a water-rich weathered rock stratum under semiopen under-pressure mode. As a solution to this problem, a calculation model was established based on field measurements of the discharged soil properties, the seepage water volume, and the seepage path in Jinan Metro, China. Chamber soil sliming is a phenomenon in which chamber soil is in a thin mud state, with no pressure balance in the pressure chamber of the EPB shield and an excessive water content of the chamber soil owing to the continuous seepage of groundwater into the chamber. The chamber pressure is relatively low, which is different from the phenomenon of spewing when the chamber pressure is relatively high. A large amount of water seepage from the stratum around the tunnel excavation surface and shield to the chamber is a significant factor leading to chamber soil sliming during the construction process. It was considered that when the moisture content of the chamber soil, w, is 2wL ≤ w ≤ 3wL, slight chamber soil sliming may occur, whereas when w ≥ 3wL, serious chamber soil sliming may occur. Moreover, some measures to prevent and control the occurrence of chamber soil sliming were discussed. Controlling the advancing time and the permeability coefficient of chamber soil during construction is the most effective measure to avoid the phenomenon of soil sliming.

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.

Laboratory Test of EPB Shield Tunneling in Mixed-Face Conditions

2021 ◽  
Vol 21 (9) ◽  
pp. 04021161
Author(s):  
Xiongyu Hu ◽  
Jun Wang ◽  
Wei Fu ◽  
J. Woody Ju ◽  
Chuan He ◽  
...  
Keyword(s):  
Laboratory Test ◽  
Shield Tunneling ◽  
Epb Shield

Laboratory Model Test of EPB Shield Tunneling in a Cobble-Rich Soil

2020 ◽  
Vol 146 (10) ◽  
pp. 04020112 ◽  
Author(s):  
Xiongyu Hu ◽  
Chuan He ◽  
Gabriel Walton ◽  
Yong Fang ◽  
Guanghui Dai
Keyword(s):  
Model Test ◽  
Laboratory Model ◽  
Shield Tunneling ◽  
Laboratory Model Test ◽  
Epb Shield

A DEM-based study of the disturbance in dry sandy ground caused by EPB shield tunneling

2020 ◽  
Vol 101 ◽  
pp. 103410 ◽  
Author(s):  
Xiongyu Hu ◽  
Chuan He ◽  
Xiaohui Lai ◽  
Gabriel Walton ◽  
Wei Fu ◽  
...  
Keyword(s):  
Shield Tunneling ◽  
Sandy Ground ◽  
Epb Shield

Measured Soil Response to EPB Shield Tunneling

1983 ◽  
Vol 109 (2) ◽  
pp. 131-149 ◽  
Author(s):  
G. Wayne Clough ◽  
Bryan P. Sweeney ◽  
Richard J. Finno
Keyword(s):  
Shield Tunneling ◽  
Soil Response ◽  
Epb Shield

Research on Chamber Earth Pressure of EPB Shield Considering Soil Arching Effect

2014 ◽  
Vol 1065-1069 ◽  
pp. 373-377
Author(s):  
Jing Cao ◽  
Hai Xing Yang ◽  
Bo Liang ◽  
Hai Ming Liu
Keyword(s):  
Earth Pressure ◽  
Shield Tunnel ◽  
Pressure Balance ◽  
Soil Arching ◽  
Shield Tunneling ◽  
Arching Effect ◽  
Soil Arching Effect ◽  
Earth Pressure Balance ◽  
Tunnel Depth ◽  
Epb Shield

Chamber earth pressure is one of the significant parameters during the Earth Pressure Balance (EPB) shield construction processing. The soil arching effect is existence when the tunnel depth is enough. It is significant to consider the influence of arching effect to analyze the pressure in soil chamber in shield tunneling. In this paper, the influence of arching effect is considered to calculate the chamber earth pressure. Firstly, the soil is supposed as loose media, and the necessary buried depth of producing arching affects is deduced according to the loose media theory. Then, based on the characteristic of proper arching axis, the equation and the height of proper arch are obtained. At last, the calculation formula of minimum chamber earth pressure of EPB shield tunnel is deduced which can consider the effect of arching effect.

Control Parameters of EPB Shield Tunneling in Weathered Granite Ground and Below Existing Tunnels

2011 ◽  
Vol 243-249 ◽  
pp. 3572-3581
Author(s):  
Xing Gao Li ◽  
Da Jun Yuan ◽  
Hao Hu
Keyword(s):  
Collaborative Work ◽  
Earth Pressure ◽  
Measured Data ◽  
Second Phase ◽  
Control Parameters ◽  
Shield Tunneling ◽  
Weathered Granite ◽  
The Earth ◽  
Epb Shield ◽  
Advance Speed

The choice of reasonable parameters of EPB shield tunneling in weathered granite ground is of great importance to reduce tunneling-induced effects on existing tunnels. Combined with the practice of the EPB shield tunneling below existing interval tunnels from Kexueguan station to Dajuyuan station of Shenzhen metro line No.1, the method of design and regulation of main parameters including the earth pressure in excavation chamber, the ground conditioning, the volume of the discharged soil, the grouting control and the advance speed, of the EPB shield tunneling are studied. The practice of the below-crossing shows in the weathered granite ground, it is reasonable that the earth pressure in excavation chamber is taken as 0.15-0.2 mpa, and that FER, FIR and CF of foam are taken as 8-15, 30-50% and 3-5% respectively, and that the amount of synchronization grouting is 8-10 m3 per ring along with the injecting pressure of 0.3-0.4 mpa, and that the second phase injection is employed to control the further settlement of existing tunnels when necessary, and that the advance speed is taken as 8-10 mm/min, and as steady as possible. Meanwhile, adjustments according measured data must be performed when necessary. Moreover, the real-time monitoring and a collaborative-work environment among the Parties involved in project are also very crucial to facilitate the risk management of the below-crossing.

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