The controlling techniques on floor heave of large cross section mining roadway with complicated surrounding rock

2014 ◽  
pp. 231-236
Author(s):  
Q Zhao ◽  
Y Wang ◽  
Y Liu ◽  
H Li ◽  
J Shi ◽  
...  
Keyword(s):  
Cross Section ◽  
Surrounding Rock ◽  
Large Cross Section ◽  
Floor Heave

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.

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.

Study on the Stability of Tunnel with Large Cross Section Based on the Ultimate Strength Reduction Method

2014 ◽  
Vol 602-605 ◽  
pp. 590-593
Author(s):  
Hui Chao Zhou ◽  
Rui Jun Liu
Keyword(s):  
Cross Section ◽  
Reduction Method ◽  
Maximum Principal Stress ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Surrounding Rock ◽  
Strength Reduction Method ◽  
Large Cross Section ◽  
Strength Reduction Factor ◽  
The Stability

The stability and the instability form of tunnel surrounding rock have always been hotspot and difficulty problems in underground engineering. We combined the finite element method with the strength reduction method to study the stability of the surrounding rock in tunnel with large cross section. To study the vault settlement, ground settlement and some feature points’ displacement, we used ADINA software to establish a simulation model, from which we can get the relationship between the strength reduction factor and data such as the maximum principal stress and the maximum plastic strain. Also, with analyzing the stability of tunnel surrounding rock, we defined the safety coefficient as 2.5 at last. Then, the tunnel’s weak position during the excavation projects and corresponding strengthening measures can be found through analyzing tunnel stress condition.

Sign in / Sign up

Export Citation Format

Share Document