Study on the Coupling Effect Between Surrounding Rock and Support Structures of Tunnels

2017 ◽  
pp. 355-366 ◽  
Author(s):  
Pham Thi Nhan ◽  
Guangsheng Zhang ◽  
Viet-Nghia Nguyen ◽  
Viet Huy Le
Keyword(s):  
Coupling Effect ◽  
Surrounding Rock ◽  
Support Structures

Stability Analysis of Tunnel Surrounding Rock Based on Coupled Fluid-Solid Theory

2011 ◽  
Vol 90-93 ◽  
pp. 1900-1903
Author(s):  
Fu Ming Wang ◽  
Xiao Long Li ◽  
Yan Hui Zhong ◽  
Xiao Guang Chen
Keyword(s):  
Stability Analysis ◽  
Plastic Zone ◽  
Coupling Effect ◽  
Plastic Zone Size ◽  
Wall Rock ◽  
Surrounding Rock ◽  
Maximum Deformation ◽  
Calculation Results ◽  
The Stability ◽  
Tunnel Depth

Taking Chaijiazhuang Tunnel of Lingnan Expressway as project background, the stability analysis of surrounding rock was performed based on the coupled fluid-solid theory. The distributions of stress field, displacement field and plastic zone of rock mass after excavation of tunnel were discussed considering coupled effect between flow and stress under the condition of different rock level and tunnel depth. Compared with the calculation results of not considering coupling effect, the maximum deformation, maximum principle stress and plastic zone size of wall rock were obviously increased when considering coupling effect, which showed a remarkable influence of coupled fluid-solid effect on the stability of tunnel surrounding rock. Some conclusions were drawn and may provide some guidance to the design and construction of tunnels in water-rich strata.

scholarly journals Fatigue Performance of Tunnel Invert in Newly Designed Heavy Haul Railway Tunnel

2019 ◽  
Vol 9 (24) ◽  
pp. 5514 ◽  
Author(s):  
Cong Liu ◽  
Limin Peng ◽  
Mingfeng Lei ◽  
Chenghua Shi ◽  
Ning Liu
Keyword(s):  
Numerical Simulation ◽  
Rock Pressure ◽  
Coupling Effect ◽  
Surrounding Rock ◽  
Fatigue Performance ◽  
Railway Tunnel ◽  
Heavy Haul ◽  
Surrounding Rock Pressure ◽  
Bottom Structures ◽  
Heavy Haul Railway

The Haoji railway in China is the longest heavy haul railway in the world, including 235 tunnels located along the 1837 km railway. With the increasing axle load of the new line and the basal deterioration of the existing heavy haul railway in China, studying the fatigue performance of the newly designed tunnel structure is essential. To study the coupling effect of the surrounding rock pressure and 30 t axle load train, in this study, we combined three-dimensional numerical simulation and three-point bending fatigue tests to investigate the fatigue performance of the basal structures. The results of numerical simulation indicate that the center of the inverted arch secondary lining is the position vulnerable to fatigue in the lower tunnel structures; the surrounding rock pressure performance exerts a stronger influence on the stress state of the vulnerable position than the dynamic train loads. The S–N formula obtained from the experiment showed that the fatigue life of tunnel bottom structures decreases with increasing surrounding rock pressure and dynamic load. In typical grade V surrounding rock and 30 t axle loads, fatigue failure will not occur in the newly designed tunnel bottom structures within 100 years if bedrock defects are lacking and pressure of surrounding rock is not excessive.

scholarly journals Research on the Reasonable Coal Pillar Width and Surrounding Rock Supporting Optimization of Gob-Side Entry under Inclined Seam Condition

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Li-li Jiang ◽  
Zeng-qiang Yang ◽  
Gang-wei Li
Keyword(s):  
Stress Field ◽  
Control Mechanism ◽  
Coupling Effect ◽  
Coal Pillar ◽  
Surrounding Rock ◽  
Control Technology ◽  
Pillar Width ◽  
Monitoring Methods ◽  
Anchor Cable ◽  
Surrounding Rock Control

In order to study the optimal coal pillar width and surrounding rock control mechanism of gob-side entry under inclined seam condition, the 130205 return air entry adjacent to 130203 gob in Yangchangwan No. 1 well is taken as a typical engineering background. By means of engineering background analysis, theoretical analysis based on inside and outside stress field, numerical simulation by FLAC3D software, and in situ industrial test and relevant monitoring methods, the optimal coal pillar width and surrounding rock control technology are obtained. The results show that the influence range of inside stress field is about 12.2∼12.8 m based on theoretical calculation result; under the influence of 10 m coal column, the overall deformation of the roadway is relatively small and within the reasonable range of engineering construction, so the width of the coal pillar along the return air roadway is set to 10 m which is more reasonable; the cross-section characteristics of special-shaped roadway lead to asymmetric stress distribution and fragmentation of surrounding rock, and then the asymmetric surrounding rock control technology under the coupling effect of roof prestressed anchor + high-strength single anchor cable + truss anchor cable support is proposed. The monitoring results of this support method are effective for the maintenance of gob-side entry, and the study conclusions provide new guidance for the surrounding rock control mechanism of gob-side entry under inclined seam conditions.

scholarly journals Research on the escape mechanism and influencing factors of harmful gas induced by blasting excavation in deep rock tunnel

2021 ◽  
Author(s):  
Yi Luo ◽  
Hangli Gong ◽  
Dengxing Qu ◽  
Xinping Li ◽  
Shaohua Hu ◽  
...  
Keyword(s):  
Coupling Effect ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
Water Soluble ◽  
Damage Effect ◽  
Escape Mechanism ◽  
Blasting Excavation ◽  
Deep Rock ◽  
Explosion Load

Abstract The escape of toxic and harmful gases is a common disaster effect in tunnel engineering. Frequent drilling and blasting excavation disturbances under high in-situ stress environment will inevitably lead to cumulative damage effect on surrounding rock, which will increase the permeability coefficient of surrounding rock, increase the risk of toxic and harmful gas escape, and seriously endanger construction safety. In this paper, based on real-time monitoring data of harmful gases during blasting and excavation of Yuelongmen Tunnel on Chengdu-Lanzhou Railway, this study summarized laws and distribution characteristics of harmful gas escape intensified by the blasting excavation, and the effectiveness of shotcreting and grouting for water blocking to inhibit gas escape is verified. Then, taking water-containing and gas-containing voids as carriers, considering the influence of different in-situ stress, explosion load and void parameters (including void pressure, void diameter and distance between void and tunnel), to carry out research on the escape mechanism of water-soluble (H 2 S) and insoluble (CH 4 ) toxic and harmful gases under the coupling effect of stress-seepage-damage. The relationship between the amount of harmful gas escaped and the damage degree of the surrounding rock of the tunnel is analyzed, and the functional relationship between it and the in-situ stress, explosion load and cave parameters is established. The results further demonstrate that the amount of escaped harmful gases, such as methane and H 2 S is closely related to lithology of surrounding rock, occurrence conditions of the deep rock mass, development degree of structural fractures and void parameters. The damage of surrounding rock caused by dynamic disturbance during blasting excavation is the main reason of aggravating harmful gas escape. The research results can provide a theoretical reference for preventing harmful gas from escaping in the similar engineering construction.

scholarly journals Experimental Study on the Temperature Field of Cold Region Tunnel under Various Groundwater Seepage Velocities

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Shiding Cao ◽  
Taishan Lu ◽  
Bo Zheng ◽  
Guozhu Zhang
Keyword(s):  
Temperature Field ◽  
Coupling Effect ◽  
Calculation Model ◽  
Surrounding Rock ◽  
Laboratory Model ◽  
Interface Temperature ◽  
Cold Region ◽  
Seepage Velocity ◽  
Groundwater Seepage ◽  
Tunnel Cross Section

Groundwater seepage significantly affects the temperature field of a cold region tunnel. Laboratory model tests are carried out to evaluate its effects, yielding four main results. First, groundwater seepage can increase tunnel air temperature and decrease the thickness and length of the tunnel insulation layer. Second, groundwater seepage and tunnel ventilation exert a coupling effect on the surrounding rock temperature. This effect is related to the surrounding rock depth. Third, the influence of the groundwater seepage velocity on the temperature of the interface between the lining and surrounding rock demonstrates a spatial difference, and the groundwater seepage leads to an uneven temperature distribution at the interface between the lining and surrounding rock. Furthermore, under groundwater seepage, the shape and size of the tunnel cross section have significant effects on the interface temperature. Fourth, the cold region tunnel has an antifreezing capability that is mainly related to the frost heaving of the surrounding rock and the groundwater seepage velocity. This capability should be fully utilized in the design of cold region tunnels. The experimental data presented can be used to verify the reliability of the theoretical calculation model for tunnel temperatures in cold regions.

scholarly journals Research on Pressure Relief Hole Parameters Based on Abutment Pressure Distribution Pattern

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jian Hao ◽  
Hua Bian ◽  
Yongkui Shi ◽  
Anfa Chen ◽  
Jiankang Liu ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Distribution Pattern ◽  
Abutment Pressure ◽  
Coupling Effect ◽  
Large Diameter ◽  
Small Diameter ◽  
Surrounding Rock ◽  
Pressure Relief ◽  
Plastic Failure ◽  
Small Pore

Borehole pressure relief technology is an effective way to reduce the elastic energy in the surrounding rock of deep roadways, thereby reducing the risk of regional rock bursts. To avoid large deformation of the roadway caused by pressure relief holes with large diameters and insufficient pressure relief with small pore diameters, this study proposes precise pressure relief holes with nonequal diameters in order to achieve strong pressure relief with minimal disturbance based on the abutment pressure distribution pattern. To verify the pressure relief effect of the nonequal diameter holes, numerical simulations were performed in FLAC3D. This study investigated stress field, deformation laws, and plastic failure zone of roadway surrounding rock with 100 mm pressure relief holes, nonequal diameter precision pressure relief hole (100 mm + 300 mm), and 300 mm pressure relief holes. The simulation results show that, as the diameter of the pressure relief hole increases, the coupling effect of evenly spaced adjacent pressure relief holes is strengthened, thus improving the pressure relief efficiency. When pressure relief holes of nonequal diameter are adopted, the stress environment of the surrounding rock is clearly improved compared to100 mm pressure relief holes, and the plastic failure range increased by 2-3 times. The roof-to-floor convergence with nonequal diameter is 30.8% that of 300 mm pressure relief holes and 41% that of 100 mm pressure relief holes. Furthermore, the rib displacement is 30.4% and 46.9% that of 300 mm and 100 mm pressure relief holes, respectively. Thus, precise pressure relief holes with nonequal diameter provide both strong pressure relief associated with large diameter holes and small disturbance of small diameter of small holes. This study provides a reference for precise pressure relief application with pressure relief holes.

scholarly journals Study on the Stability of a Transition Section from Soft to Hard Surrounding Rock Based on the Solid-Fluid Coupling Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Qizhi Hu ◽  
Yixin Tang ◽  
Zhigang Ding
Keyword(s):  
Stress Field ◽  
Displacement Field ◽  
Coupling Effect ◽  
Surrounding Rock ◽  
Guizhou Province ◽  
Seepage Field ◽  
Support Structure ◽  
Transition Section ◽  
Design Values ◽  
The Stability

To study the stability of a transition section of a tunnel from soft to hard surrounding rock under seepage conditions, FLAC3D software was used to numerically simulate the transition section of the Laomushan Tunnel from the Shiqian to Yuping (Dalong) Expressways in Guizhou Province, China, and to explore different working conditions. The characterization of the tunnel seepage field, stress field, and displacement field and the analysis of the force of the primary lining support structure describe the influence of the seepage field on the stress field distribution and displacement field changes. The reliability of the calculation results is verified by comparison with displacement measurements collected during field monitoring. The design values of the primary support structure parameters of the transition section from soft to hard surrounding rock of the Laomushan Tunnel basically met the strength requirements. The research results provide references for the design and construction of similar projects.

scholarly journals Field Monitoring of the Deformation and Internal Forces of the Surrounding Rock and Support Structures in the Construction of a Super-Span High-Speed Railway Tunnel—A Case Study

2020 ◽  
Vol 10 (15) ◽  
pp. 5182
Author(s):  
Daoping Liu ◽  
Dingli Zhang ◽  
Qian Fang ◽  
Zhenyu Sun ◽  
Jiwei Luo ◽  
...  
Keyword(s):  
Contact Pressure ◽  
High Speed ◽  
Field Monitoring ◽  
Surrounding Rock ◽  
Internal Stresses ◽  
Support Structures ◽  
Axial Forces ◽  
Geological Conditions ◽  
Internal Forces

A super-span tunnel that has the characteristics of a large excavation area, a small high-span ratio and a significant spatial effect exhibits a complex mechanical response during the excavation process. In this paper, taking the Badaling Great Wall station in Beijing, China as the engineering background, a case study of field monitoring a super-span tunnel has been presented. A typical monitoring section was selected in the super-span transition section of the tunnel and the deformation and forces of both the surrounding rock and the support structures were systematically monitored. The dynamic evolution and the spatial distribution characteristics of the monitoring data, including the internal displacement of the surrounding rock, the tunnel displacement, the contact pressure between the surrounding rock and the primary supports, the contact pressure between the primary and secondary supports, the axial forces in the bolts and cables, the internal forces in both the steel arches and the secondary supports and the internal stresses of the surrounding rock, were analyzed. The results of the monitoring and the analyses have shown that the deformation and the forces acting on both the surrounding rock and the tunnel’s lining are directly related to the construction procedures, the geological conditions and the locations in the super-span tunnel. According to the results, a few suggestions to improve the construction of the tunnel have been proposed.

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