The Study on a New Loads Calculation Method of Multi-Arch and Extra Large Cross Section Tunnels

2011 ◽  
Vol 94-96 ◽  
pp. 1159-1165 ◽  
Author(s):  
Chong Bang Xu ◽  
Cai Chu Xia ◽  
Hua Lao Wang
Keyword(s):  
Cross Section ◽  
Calculation Method ◽  
Construction Cost ◽  
Surrounding Rock ◽  
Construction Technology ◽  
Large Cross Section ◽  
Construction Procedure ◽  
Field Situation ◽  
Temporary Support ◽  
Large Sections

Increasing numbers of tunnels adopt super large sections due to the advance of design and construction technology, but the calculation method for the loose loads of such tunnels still follows the traditional method for tunnels constructed by the method of whole face excavation. The calculated loads using such method are always lager than their actual values of super large sections tunnels, and as a result the supports for such tunnels are too conservative which lead to unnecessary construction cost. As said, a new calculation method for the loose loads of multi-arch and extra large cross section tunnels (MELCST) is proposed in this paper considering the characteristics of construction for such tunnels. The method accounts for the influences caused by the multi-step construction procedure and temporary support on tunnels. Compared with old methods, this method is more practical and close to field situation, which provides a new idea for calculating surrounding rock loose loads in MELCST. This new method is demonstrated using Luohanshan tunnel of airport-highway in Fuzhou city, China.

Application Study of the Calculation Method for Loads of Multi-Arch and Extra Large Cross Section Tunnels in Double-Side Drifts Construction Method

2012 ◽  
Vol 204-208 ◽  
pp. 1488-1491
Author(s):  
Chong Bang Xu ◽  
Xu Zhao
Keyword(s):  
Cross Section ◽  
Calculation Method ◽  
Construction Method ◽  
New Method ◽  
Large Cross Section ◽  
Application Study ◽  
Construction Sequence ◽  
Construction Procedure ◽  
Temporary Support ◽  
Distribution Mode

The calculation method for load of multi-arch and extra large cross section tunnels (MELCST) is a new method accounting for the influences caused by the multi-step construction procedure and temporary support on tunnels. The paper analyses the application of the method in the double-side drift construction method, and gives the distribution mode and the value of loose loads in various construction sequence, example analysis is also given through Luohanshan tunnel.

Instability Mechanism of Surrounding Rock for Super-Large Cross Section at High-Speed Railway Tunnel Portal

2013 ◽  
Vol 353-356 ◽  
pp. 1597-1603
Author(s):  
Shuang Lan Wu ◽  
Shi Hao Yang ◽  
Xue Wen Zhang
Keyword(s):  
High Speed ◽  
Surrounding Rock ◽  
Instability Mechanism ◽  
Large Cross Section ◽  
Railway Tunnel ◽  
High Speed Railway ◽  
Construction Procedure ◽  
In Situ Conditions ◽  
Major Factors

Difficulties of tunnel construction mainly appear in the entrance and exit stage, some adverse geological problems may occur. In terms of the tunnel at the Changsha-Kunming section of the Shanghai-Kunming passenger line, firstly, adverse geological phenomena at tunnel exits was described. Secondly, major factors leading to disasters were listed, including geology, hydrology and construction procedure. Combined with in-situ conditions, Finite Element Method (FEM) was used to analyze the instability mechanism of surrounding rock after the upper arch gate was excavated by three-bench seven-step exaction method. At last, through comparison between computed result and measuring data, several basic conclusions was obtained. It can make much sense to similar engineering.

The Economic Analysis of Large Cross-Section Conductor in ±800kV DC Project

2013 ◽  
Vol 753-755 ◽  
pp. 3194-3197
Author(s):  
Hai Ying Zhou ◽  
Chun Lei Bu ◽  
Ming Jiang
Keyword(s):  
Economic Analysis ◽  
Cross Section ◽  
Transmission Lines ◽  
Social Economic ◽  
Construction Cost ◽  
Economic Benefits ◽  
Large Cross Section ◽  
Safe Operation ◽  
Key Issues

Conductor scheme is one of most key issues in the design of the transmission lines project, and it is significant for the construction cost and safe operation of transmission lines project. It can be aslo concluded from analysis on application of existing conductor that the appropriate decrease of number of bundle conductor and increase of the conductor cross-section will reduce lines loss, which has remarkable social-economic benefits. In this paper, the economic analysis of large cross-section conductor is conducted based on ±800kV DC Project. Some useful suggestions are given.

The Economic Analysis of Large Cross-Section Conductor in UHVDC Project

2013 ◽  
Vol 753-755 ◽  
pp. 3198-3200
Author(s):  
Hai Ying Zhou ◽  
Chun Lei Bu ◽  
Ming Jiang
Keyword(s):  
Economic Analysis ◽  
Transmission Line ◽  
Cross Section ◽  
Social Economic ◽  
Construction Cost ◽  
Economic Benefits ◽  
Large Cross Section ◽  
Safe Operation ◽  
Key Issues ◽  
Line Loss

Conductor scheme is one of key issues in the design of the UHVDC transmission project, and it is significant for the construction cost and safe operation of transmission line. It can be concluded from analysis on application of existing conductor that the appropriate decrease in number of bundle conductor and increase of the conductor cross-section will reduce line loss, which has remarkable social-economic benefits. In this paper, the economic analysis of large cross-section conductor is conducted based on UHVDC Project. Some useful suggestions are given.

The Grouting Technology of Large-Section Highway Tunnel in Water-Rich Karst Formations

2013 ◽  
Vol 838-841 ◽  
pp. 1441-1446
Author(s):  
Chao Yue Zhou ◽  
Yong Fang ◽  
Ya Peng Fu ◽  
Ge Cui
Keyword(s):  
Cross Section ◽  
Field Tests ◽  
Operation Technique ◽  
Tunnel Construction ◽  
Construction Technology ◽  
Large Cross Section ◽  
Large Section ◽  
Highway Tunnel ◽  
Grouting Materials

It is a challenge to deal with karst in the construction of large cross-section tunnel. Under the background of Shuangbei Highway Tunnel, a new kind of grouting technology is introduced. According to hydrogeology, field tests are carried out to select grouting materials and proportion of mixture. Combined with the project practice, grouting construction technology is discussed such as grouting equipments, grouting parameters, operation technique, grouting ending standards. It has been proved that the technology is effective in tunnel construction.

Design of Key Process Parameters Test-Bench for 1250mm2 Large Cross-Section Conductor Tension Stringing

2014 ◽  
Vol 1065-1069 ◽  
pp. 2058-2062
Author(s):  
Yong Jun Xia ◽  
Wen Ming Mei ◽  
Chun Hua Hu ◽  
Jin Miao Zhang
Keyword(s):  
Cross Section ◽  
Test Bench ◽  
Test System ◽  
Test Methods ◽  
Test Scheme ◽  
Construction Technology ◽  
Large Cross Section ◽  
Force Analysis ◽  
Limit Test ◽  
Design And Manufacture

This document proposed the test scheme of limit Test-bench structural system under the setting-out conditions of simulating critical state and completed the design and manufacture of the test system through conducting investigation on test methods and equipment of tension stringing construction process, combining the 1,250mm2 large cross-section conductor and construction technology requirements and based on functional positioning, optimization of combined design and force analysis of Test-bench, mechanics analysis of various parts and their connection as well as allowable stress method check. This system was closer to the actual stringing working conditions, and the obtained data were more reasonable and exact and meet the actual engineering demand. In addition, the reliability of this test system has been verified through the test of 1,250mm2 third-class large cross-section conductor.

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.

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