Research on the construction risk control technology of shield tunnel underneath an operational railway in sand pebble formation: a case study

2018 ◽  
Vol 24 (10) ◽  
pp. 1558-1572 ◽  
Author(s):  
Mingfeng Lei ◽  
Dayong Lin ◽  
Qiyou Huang ◽  
Chenghua Shi ◽  
Linchong Huang
Keyword(s):  
Risk Control ◽  
Shield Tunnel ◽  
Control Technology ◽  
Construction Risk

Case Study of the St. Paul Companies Virtual Office for the Risk Control Division

2011 ◽  
pp. 60-71
Author(s):  
Nancy Johnson
Keyword(s):  
Working Conditions ◽  
Risk Control ◽  
Working Environment ◽  
Personal Lives ◽  
Virtual Office ◽  
Office Space ◽  
Construction Risk ◽  
Remote Sites ◽  
Control Division

The St. Paul Companies has successfully implemented a virtual office (VO) working environment for their US distributed construction risk control and commercial risk control employees over the past six years. The program goals of operating more cost effectively, increasing contact of the risk control specialists with their customers, and reducing office space costs for The St. Paul Companies have been met. There are many good practices that have been developed over the six years of offering the program, and more refinements and changes planned. As the communications and computer technologies advance, facilitation of working from remote sites improves. While it is easier for employees to work from remote sites, maintaining the boundaries between work and personal lives is more challenging. Improving the VO employees’ and corporate employees’ understanding of the other’s working conditions is necessary to improve relationships and the acceptance of change. The concept of VO work is well established within the organization, and the demand for it is growing.

Case Study of the St. Paul Companies' Virtual Office for the Risk Control Division

2001 ◽  
pp. 148-161 ◽  
Author(s):  
Nancy Johnson
Keyword(s):  
Working Conditions ◽  
Risk Control ◽  
Working Environment ◽  
Personal Lives ◽  
Virtual Office ◽  
Office Space ◽  
Construction Risk ◽  
Remote Sites ◽  
Control Division

The St. Paul Companies has successfully implemented a virtual office (VO) working environment for its construction risk control and commercial risk control employees over the past six years. The program goals of operating more cost-effectively, increasing contact of the risk control specialists with their customers, and reducing office space costs for The St. Paul Companies have been met. There are many good practices that have been developed over the six years of offering the program, and more refinements and changes planned. As the communications and computer technologies advance, facilitation of working from remote sites improves. While it is easier for employees to work from remote sites, maintaining the boundaries between work and personal lives is more challenging. Improving the VO employees’ and corporate employees’ understanding of the others’ working conditions is necessary to improve relationships and the acceptance of change. The concept of VO work is well established within the organization, and the demand for it is growing.

scholarly journals Risk Control Standard and Construction Control Technology of Shield Tunnel Passing through Irregular-Plate Bridge

Symmetry ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1331
Author(s):  
Yougang Hu ◽  
Ping He
Keyword(s):  
Risk Control ◽  
Shield Tunnel ◽  
Foundation Settlement ◽  
Control Technology ◽  
Ground Settlement ◽  
Subway Tunnel ◽  
Feasible Method ◽  
Key Points ◽  
The Relationship ◽  
Beijing Subway

As a kind of statically-indeterminate point-support structure, the irregular-plate bridge (IPB) is extremely sensitive to the settlement of pier columns, and the stress of the plate is complicated. Because of the limitation of environmental conditions, the newly-built subway circular symmetric shield tunnel needs to pass the pier foundation of the IPB perpendicularly. To control the engineering risks, the pier settlement value must be known, and measures should be taken to reduce the settlement. This paper takes the project of the Beijing subway circular symmetric shield tunnels passing the existing IPB of the Guang’anmen Bridge as an example. First, the stress characteristics and settlement control standards of the IPB are analyzed, and then the technical scheme of synchronous jacking and key points of risk control during the construction of the shield passing the IPB are put forward. The relationship between the excavation face pressure of the shield tunnel and pier foundation settlement, and the ground settlement, are then analyzed. Finally, structural cracking after construction is analyzed, and the analysis shows that synchronous jacking technology can effectively control the settlement value of the subway tunnel passing the IPB. The technology is a feasible method for controlling the safety of a tunnel passing through a sensitive, statically-indeterminate bridge, and this work is a successful experience for similar major risk projects.

Case Study of the St. Paul Companies Virtual Office for the Risk Control Division

2011 ◽  
pp. 60-71
Author(s):  
Nancy J. Johnson
Keyword(s):  
Working Conditions ◽  
Risk Control ◽  
Working Environment ◽  
Personal Lives ◽  
Virtual Office ◽  
Office Space ◽  
Construction Risk ◽  
Remote Sites ◽  
Control Division

The St. Paul Companies has successfully implemented a virtual office (VO) working environment for their U.S. distributed construction risk control and commercial risk control employees over the past six years. The program goals of operating more cost effectively, increasing contact of the risk control specialists with their customers, and reducing office space costs for The St. Paul Companies have been met. There are many good practices that have been developed over the six years of offering the program, and more refinements and changes planned. As the communications and computer technologies advance, facilitation of working from remote sites improves. While it is easier for employees to work from remote sites, maintaining the boundaries between work and personal lives is more challenging. Improving the VO employees and corporate employees understanding of the others working conditions is necessary to improve relationships and the acceptance of change. The concept of VO work is well established within the organization, and the demand for it is growing.

Key Construction Technologies for Large River-Crossing Slurry Shield Tunnel: Case Study

2021 ◽  
Vol 34 (2) ◽  
pp. 04020118
Author(s):  
Song Zhou ◽  
Guan-Lin Ye ◽  
Lei Han ◽  
Wang Jian-Hua
Keyword(s):  
Large River ◽  
Shield Tunnel ◽  
Slurry Shield

Soil-water inrush induced shield tunnel lining damage and its stabilization: A case study

2020 ◽  
Vol 97 ◽  
pp. 103290 ◽  
Author(s):  
Linchong Huang ◽  
Jianjun Ma ◽  
Mingfeng Lei ◽  
Linghui Liu ◽  
Yuexiang Lin ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Inrush ◽  
Tunnel Lining ◽  
Shield Tunnel

scholarly journals Experimental Study on the Transverse Effective Bending Rigidity of Segmental Lining Structures

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Yong-feng Tang ◽  
Han-cheng Chen ◽  
Zhen-wei Ye ◽  
Ting-jin Liu ◽  
Yu-bing Yang
Keyword(s):  
Regression Equation ◽  
Shield Tunnel ◽  
Outer Diameter ◽  
Test Results ◽  
Bending Rigidity ◽  
Segmental Lining ◽  
Ring Model ◽  
Scale Models ◽  
Elastic Stage

The transverse effective rigidity ratio is a key parameter when the uniform rigidity ring model is adopted to design or numerically analyse segmental lining structures commonly used on a shield-driven tunnel. Traditionally, the transverse effective rigidity ratio η is treated as a constant, which can be evaluated through theoretical analysis and model tests. In this study, scale models were designed and tested to investigate the variation of the transverse effective rigidity ratio in the segmental linings’ flattening deformation process. The test results suggested that in the elastic stage, the transverse effective rigidity ratio fluctuated between 0.667 and 0.734 for the stagger-jointed rings and fluctuated between 0.503 and 0.642 for the straight-jointed rings. When segmental linings were squashed and started to crack at the circumferential joints, the transverse effective rigidity ratio decreases sharply. Then, a regression equation was obtained to fit the variation trend of η with the increase of horizontal convergence to the outer-diameter ratio (ΔD/Dout). Finally, in a case study, the regression equation was adapted to determine the value of η of an operated shield tunnel which was once surcharged accidentally and deformed severely so as to numerically predict the prospective deformation induced by the upcoming adjacent excavation. Numerical results indicated that as the value of η decreases, the horizontal convergences of shield tunnel induced by adjacent excavation increase significantly and even more than doubled in the case study. Comparatively, through taking account of the operating tunnels’ exiting transverse deformation, the predicted deformation tends to be unfavourable.

scholarly journals Zoning Control Technology of Gob-Side Roadway Driving with Small Coal Pillar Facing Mining in a Special Isolated Island Working Face: A Case Study

2021 ◽  
Vol 11 (22) ◽  
pp. 10744
Author(s):  
Changliang Han ◽  
Houqiang Yang ◽  
Nong Zhang ◽  
Rijian Deng ◽  
Yuxin Guo
Keyword(s):  
Control Method ◽  
Coal Pillar ◽  
Control Technology ◽  
Stability Zone ◽  
Pressure Relief ◽  
Collaborative Control ◽  
Working Face ◽  
Underground Coal Mines ◽  
Engineering Practices

The gob-side roadway in an isolated island working face is a typical representative of a strong mining roadway, which seriously restricts the efficient and safe production of underground coal mines. With the engineering background of the main transportation roadway 1513 (MTR 1513) of the Xinyi Coal Mine, this paper introduces the engineering case of gob-side roadway driving with small coal-pillar facing mining in an isolated island working face under the alternate mining of wide and narrow working faces. Through comprehensive research methods, we studied zoning disturbance deformation characteristics and stress evolution law of gob-side roadway driving under face mining. Based on the characteristics of zoning disturbance, MTR 1513 is divided into three zones, which are the heading face mining zone, the mining influenced zone, and the mining stability zone. A collaborative control technology using pressure relief and anchoring is proposed, and the differentiated control method is formed for the three zones. For the heading face mining zone, the control method of anchoring first and then pressure relief is adopted; for the mining influenced zone, the control idea of synchronous coordination of pressure relief and anchorage is adopted; for the mining stability zone, the control method of anchoring without pressure relief is adopted. Engineering practices show that the disturbance influence distance of working face 1511 on MTR 1513 changes from 110 m advanced to 175 m delay. At this time, the surrounding rock deformation is effectively controlled, which verified the rationality of the division and the feasibility of three zoning control technology. The research results can provide reference for gob-side roadway driving with small coal pillar facing mining in a special isolated island working face.

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