Numerical Simulation of Ultra-Shallow Buried Large-Span Double-Arch Tunnel Excavated under an Expressway

The temporal and spatial effects of a complicated excavation process are vital for an ultra-shallow buried large-span double-arch tunnel excavated under an expressway in service. Numerical simulations are urgent and necessary to understand the effect of the total construction process. Taking Xiamen Haicang tunnel as a research object, the total excavation process of three pilot tunnels and the three-bench reserved core soil method of an ultra-shallow buried large-span double-arch tunnel with a fault fracture zone under an expressway was simulated using software FLAC3D. The deformation of the surface, surrounding rock, underground pipelines, tunnel support structure and partition wall of the three pilot tunnels and the main tunnel was analyzed, and the dangerous areas and time nodes were obtained. When the tunnel was excavated to the fault fracture zone, the deformation of the surface and surrounding rock increased significantly. The rock and soil within 20 m behind the excavation surface of the pilot tunnel were greatly disturbed by the excavation. During the excavation of the main tunnel, the horizontal displacement of the middle partition wall moved slightly towards the main tunnel excavated first. The research results can provide a reference for the construction design of double-arch tunnels.

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Displacement analysis of surrounding rock deformation of Baochang tunnel in Yunnan

E3S Web of Conferences ◽

10.1051/e3sconf/201913604018 ◽

2019 ◽

Vol 136 ◽

pp. 04018

Author(s):

Lianghan Zhang ◽

Xiaolong Li ◽

Xinyun Ma ◽

Hongyan Guo ◽

Ke Li

Keyword(s):

Horizontal Displacement ◽

Construction Safety ◽

Surrounding Rock ◽

Tunnel Excavation ◽

Partition Wall ◽

Excavation Process ◽

Tunnel Monitoring ◽

Double Wall ◽

Wall Method ◽

Surrounding Rock Deformation

According to the problem of deformation of surrounding rock when the double-wall method is adopted in the tunnel, the five tunnel monitoring points are set in the tunnel vault, arch waist and arch foot to simulate the tunnel excavation process. The surrounding rock is deformed, and the excavation of the middle guide hole makes the deformation of the surrounding rock reach 7.2mm. After the removal of the middle partition wall, the deformation reaches the maximum, which is 8.4mm. The horizontal displacement starts to increase rapidly, and the maximum is 5.3mm. According to the analysis results, the surrounding rock above the tunnel should be reinforced in time, and the deformation of the surrounding rock after the removal of the middle partition wall should be paid attention to ensure the construction safety and provide reference for future construction.

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Study on the Geological Forecast and Treatment for Water-Bearing Fault of the Qingdao Kiaochow Bay Subsea Tunnel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.671-674.1114 ◽

2013 ◽

Vol 671-674 ◽

pp. 1114-1121

Author(s):

Zhi Peng Li ◽

Shu Cai Li ◽

Qing Song Zhang ◽

De Ming Wang ◽

Bing Hui ◽

...

Keyword(s):

Fracture Zone ◽

Surrounding Rock ◽

Tunnel Excavation ◽

Bearing Fault ◽

Grouting Material ◽

Fault Fracture Zone ◽

Analysis Of Results ◽

Subsea Tunnel ◽

The Stability ◽

Fissure Water

Water-bearing fault of subsea tunnel has fissure water developed, fractured surrounding rock with low strength, which gets a risk of sudden water inflow and affects the tunnel security. This paper takes the geological forecast and treatment for water-bearing fault of the Qingdao kiaochow bay subsea tunnel for example, according to the water assignment characteristics, using the detect method of TEM and advance borehole to make accurate decision for the position of water-bearing body、the scale of fracture zone and the inflow of water. Through the analysis of results, the grouting form, materials and parameters are chosen and adjusted. The grouting material seals the water flowing fracture, forming water-stopping curtain outside tunnel excavation contour line and strengthening the fault fracture zone to improve the stability of rock.

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Construction Simulation and Stress Characteristics of Large Span Tunnel Crossing Fault Fracture Zone

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/189/2/022004 ◽

2018 ◽

Vol 189 ◽

pp. 022004

Author(s):

Tianyuan Xu ◽

Li Yu ◽

Minjin Cai

Keyword(s):

Fracture Zone ◽

Construction Simulation ◽

Large Span ◽

Fault Fracture Zone

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Effect of a Fault Fracture Zone on the Stability of Tunnel-Surrounding Rock

International Journal of Geomechanics ◽

10.1061/(asce)gm.1943-5622.0000837 ◽

2017 ◽

Vol 17 (6) ◽

pp. 04016135 ◽

Cited By ~ 23

Author(s):

Yingchao Wang ◽

Hongwen Jing ◽

Haijian Su ◽

Jiangyue Xie

Keyword(s):

Fracture Zone ◽

Surrounding Rock ◽

Fault Fracture Zone ◽

The Stability

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Research on the Mechnical Characteristics of Primary Supports in Guanjiao Tunnel Fault Fracture Zone and its Influence Zone by Field Tests

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.105-107.1203 ◽

2011 ◽

Vol 105-107 ◽

pp. 1203-1210 ◽

Cited By ~ 1

Author(s):

Da Li ◽

Zhan Fu Luo ◽

Yong Sheng Li

Keyword(s):

Fracture Zone ◽

Field Tests ◽

Surrounding Rock ◽

Tunnel Construction ◽

Railway Tunnel ◽

Influence Zone ◽

Geological Conditions ◽

Fault Fracture Zone ◽

Under Construction ◽

Primary Support

The tunnel which excavated through the fault fracture zone is still one of the difficulties in the current tunnel construction. Guanjiao tunnel is the longest high-altitude tunnel in the world, and also the longest railway tunnel which is under construction in China. The 9# shaft which located in Erlang fault fracture zone with several faults, complicated geological conditions is difficult to excavate. In the representative section of F3 fault and its influence zone, F22 fault fracture zone, the monitoring tests on contact pressure between surrounding rock and primary support and stress of steel arch is conducted. According to the above monitoring results，the project recommendations are proposed to ensure the smooth construction of tunnel.

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Quantitative Study on Empirical Strength Parameters of Extremely Fractured Phyllite Based on Fractal Theory

Advances in Materials Science and Engineering ◽

10.1155/2021/2241351 ◽

2021 ◽

Vol 2021 ◽

pp. 1-14

Author(s):

Yongbin Xie ◽

Xiaoyu Yang ◽

Jianhua Dong ◽

Guosheng Liu

Keyword(s):

Fractal Dimension ◽

Fracture Zone ◽

Shear Test ◽

Fractal Theory ◽

Surrounding Rock ◽

Strength Parameter ◽

Strength Parameters ◽

Significant Difference ◽

Fault Fracture Zone ◽

Fractal Description

Extremely broken phyllite is widely distributed and is easily seen in engineering construction. Aiming at the problem that the empirical strength parameters of extremely broken surrounding rock have intense subjectivity and significant difference, based on the characteristics of the existence of particle group state in the highly broken surrounding rock, the fractal theory and large-scale direct shear test are used, the fractal description of polar broken phyllite samples with different pile numbers in fault fracture zone of Qinyu Tunnel is carried out, and the fractal dimensions and empirical strength parameters of each sample are determined. Based on a fractal description and large shear test, the functional relationship between fractal dimension and empirical strength parameter of extremely broken phyllite in fault fracture zone is established, and the quantitative value method of empirical strength parameter determined by fractal dimension of extremely broken phyllite is given, which provides ideas for the quantitative value of empirical strength parameter of the similar extremely broken surrounding rock.

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Study on Mechanical Properties and Control Technology of Surrounding Rock in the Fracture Zone of a Roadway

Shock and Vibration ◽

10.1155/2021/6628593 ◽

2021 ◽

Vol 2021 ◽

pp. 1-14

Author(s):

Yushun Yang ◽

Zhiming Fang ◽

Guangying Ji ◽

Baigao Zhao ◽

Sijiang Wei

Keyword(s):

Rock Mass ◽

Fracture Zone ◽

Rock Fracture ◽

Industrial Test ◽

Surrounding Rock ◽

Mine Pressure ◽

Three Dimensional Model ◽

Silty Mudstone ◽

Fracture Development ◽

Fault Fracture Zone

We aim at the problem of the large deformation and difficult control of surrounding rock when passing through a fault fracture zone in the centralized rail transportation lane along the south wing of Xinyi Coal Mine; the stress environment and failure mechanism of surrounding rock are analyzed through field investigation, numerical simulation, and field industrial test. The instability of the surrounding rock in the fault fracture zone was considered to be the result of the joint effect of the surrounding rock fracture development, lithology differences, water gushing occurrences, low strength of the original support, high in situ stress, and fault-related tectonic stress. Rock blocks are collected on site at the fracture zone, and the remoulded samples are prepared for mechanical experiments in the laboratory. The basic mechanical parameters of the roadway passing through silty mudstone, sand-mudstone interlayer, and fine sandstone were analyzed. A three-dimensional model is established to analyze the distributions of the stress, deformation, and plastic area in the surrounding rock mass after the tunnel passes through, considering both a single-rock mass and a multilayer-rock mass. Based on the above analysis, the “closed support + shotcrete + grouting + anchor mesh cable coupling support” is proposed. Three stations were arranged on site to observe the mine pressure, and the field industrial test shows that, within the 100 days of observation, the maximum roof-to-floor convergence is 38 mm, while the maximum horizontal convergence is 56 mm. The overall reinforcement effect of the roadway is good, the surface is smooth, and there is no phenomenon of concrete cracking and bolt fracture.

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Effect of the Location of Fault Fracture Zones on the Stability of Symmetrical Submarine Tunnels

Symmetry ◽

10.3390/sym13071111 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1111

Author(s):

Wei Fang ◽

Gang Wang ◽

Chang Wang

Keyword(s):

Safety Factor ◽

Working Conditions ◽

Axial Force ◽

Fracture Zone ◽

Bending Moment ◽

Surrounding Rock ◽

Fracture Zones ◽

Fault Fracture Zone ◽

Lining Structure ◽

The Stability

In this paper, we aim to reveal the influence of fault fracture zones on the stability of submarine tunnels and the surrounding rock under different water and drainage measures. Firstly, four typical working conditions of submarine tunnels intersecting with fault fracture zones were selected. On the basis of the typical cross section of the intersections of submarine tunnels and faults, they were divided into four working conditions. Then, the displacement and plastic zones of the surrounding rock of the tunnel were studied, and the stability of the rock surrounding the submarine tunnel was discussed. This research structure indicates that the bending moment and axial force of the lining structure of the submarine tunnel increase with increasing sealing degree, but the safety factor exhibits a downward trend. When the fault fracture zone goes through the section above the tunnel axis, the bending moment and axial force at the lining vault are greater than the other working conditions, and the displacement of the surrounding rock at the vault and spandrel is prominent. When the fault fracture zone completely passes through the tunnel, the safety factor of the lining structure is at its lowest, and the displacement of the surrounding rock at the arch waist develops laterally. When the fault fracture zone passes through the part below the tunnel axis, the arch foot displacement converges significantly, and the surrounding rock displacement exhibits a downward inclination. In addition, the plastic zone is mainly developed in the arch and the shoulder. These research results provide a reliable reference for tunnel design and excavation support.

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