scholarly journals Model Test on Impact of Surrounding Rock Deterioration on Segmental Lining Structure for Underwater Shield Tunnel with Large Cross-Section

2012 ◽  
Vol 12 ◽  
pp. 891-898 ◽  
Author(s):  
Kun Feng ◽  
Chuan He ◽  
Jimin Zhou ◽  
Zeng Zhang
Keyword(s):  
Cross Section ◽  
Model Test ◽  
Surrounding Rock ◽  
Shield Tunnel ◽  
Large Cross Section ◽  
Segmental Lining ◽  
Lining Structure

Model Test on Structural Behaviour of Underwater Shield Tunnel with Large Cross-Section Considering Assembling Modes

2011 ◽  
Vol 243-249 ◽  
pp. 3560-3564
Author(s):  
Ji Min Zhou ◽  
Chuan He ◽  
Kun Feng ◽  
Ming Qing Xiao
Keyword(s):  
Cross Section ◽  
Model Test ◽  
Yangtze River ◽  
Water Pressure ◽  
Bending Moment ◽  
Internal Force ◽  
Test System ◽  
Shield Tunnel ◽  
Large Cross Section ◽  
Study Results

Taking Nanjing Yangtze River Shield Tunnel with large cross-section (Φ14.5m) as background, the mechanical characteristic of lining structure under high hydrostatic water pressure for different segmental assembling modes is studied by large-scale similar model test. The test system can control earth pressure, uniform and non-uniform water pressure acting on lining respectively and cooperatively. The study results show that the values and distribution of deformation and internal force vary with different assembling modes. The rigidity of the whole ring for straight joint assembling is less, inducing the deformation larger and internal force smaller, which is unfavorable for waterproofing requirements. The peak positions of bending moment change with the difference of staggered joint assembling modes. Due to the smaller rigidity of K segment, the value of bending moment on that position is less. The most favorable and unfavorable assembling modes are proposed for construction design for Nanjing Yangtze River Shield Tunnel; meanwhile it can also provide important reference to the correlative project.

scholarly journals The Researches on Construction Response and Excavation Method Optimization of Extra-large Cross-section Urban Subway Tunnel

2018 ◽  
Vol 38 ◽  
pp. 03041 ◽  
Author(s):  
Bo Wu ◽  
Wei Huang ◽  
Yong Bo Zhao
Keyword(s):  
Mechanical Behavior ◽  
Cross Section ◽  
Surrounding Rock ◽  
Large Cross Section ◽  
Subway Tunnel ◽  
Construction Methods ◽  
Method Optimization ◽  
Underground Station ◽  
The City ◽  
Selection Of

In the extra-large cross-section urban subway underground station projects, the key problem is to choose the appropriate excavation method and grasp the mechanical behavior of the surrounding rock after excavation. The double side drift method is widely used in the urban subway underground station construction with extra-large cross-section in China. This paper presents the deformation characteristics of the extra-large cross-section tunnel of urban subway and a comparison with the numerical simulation results. In the city subway underground excavation of large section station, the mechanical behavior of surrounding rock change and its influence on the surrounding area mainly depend on the selection of construction methods. The convergent deformation of tunnel cavern, the subsidence of the surface and the force failure of the surrounding rock associated the construction approaches are demonstrated. This study provides a more in-depth demonstration of the way to optimize the excavation method of the extra-large cross-section tunnel to achieve the purpose of controlling the deformation of the surface and surrounding rock.

scholarly journals Experimental Study of Blasting Excavation for Large Cross-Section Tunnel in Horizontal Layered Rock Mass

2021 ◽  
Author(s):  
Jie Mei ◽  
Wanzhi Zhang ◽  
Bangshu Xu ◽  
Yongxue Zhu ◽  
Bingkun Wang
Keyword(s):  
Rock Mass ◽  
Cross Section ◽  
Surrounding Rock ◽  
Large Cross Section ◽  
Large Area ◽  
Layered Rock ◽  
Blasting Excavation ◽  
Tunnel Blasting ◽  
Layered Rock Mass ◽  
Upper Face

Abstract The drilling and blasting method is still the main method in mountain tunnel excavation. For large cross-section tunnel in horizontal layered rock mass, tunnel blasting often causes serious overbreak and underbreak. In this study, blasting excavation tests of tunnel upper face were conducted and failure mechanisms of surrounding rocks with weak beddings and joints were analyzed based on the Panlongshan tunnel. Then, the blasthole pattern, the cut mode, a variety of peripheral holes, the charge structure and the maximum single-hole charge were optimized. Compared with the failure characteristics, overbreak and underbreak, and deformations of surrounding rocks before and after optimization, the latter was better in tunnel contour forming and surrounding rock stability. The results show that after optimization, the large-area separation of vault rock mass is solved, the step-like overbreak of spandrel rock mass is reduced and the large-size rock blocks and underbreak are avoided. The maximum linear overbreak of vault, spandrel, and haunch surrounding rocks is decreased by 42.3%, 53.7% and 45.1%, respectively. The underbreak at the bottom of the upper face is reduced from -111.5 to - 16.5 cm. The average overbreak area is decreased by 61.1%. In addition, the displacements after optimization finally converge to the smaller values. The arch crown settlement and the horizontal convergence of haunch are reduced by about 21.6% and 18.3%, respectively. Furthermore, from the completion of blasting excavation to the stabilization of surrounding rock, it takes less time by using the optimized blasting scheme.

Comparative Analysis of CRD Method and Three-Bench Method with Temporary Invert

2011 ◽  
Vol 90-93 ◽  
pp. 1834-1839
Author(s):  
Ri Bin Wang ◽  
Xin Ni Lin ◽  
Hua Ping Shao ◽  
Jun Sheng Yang ◽  
Yuan Liang Huang
Keyword(s):  
Comparative Analysis ◽  
Cross Section ◽  
Economic Benefit ◽  
Surrounding Rock ◽  
Large Cross Section ◽  
Tunnel Engineering ◽  
Tunnel Collapse ◽  
Simulation Results ◽  
Construction Schedule ◽  
Supporting Force

CRD method and three-bench method with temporary invert, which are applied to shallow buried and large cross-section tunnel engineering, are discussed, and simulated by FLAC2D so as to study the variation feature of displacement field, surrounding rock disturbance and internal supporting force caused by the excavation. According to the simulation results, it is proved that CRD method, with higher safety, can control tunnel collapse effectively while three-bench method quickens construction schedule. Therefore, it is recommended that the two methods are used for excavating tunnels alternately if possible so that it will increase economic benefit.

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