scholarly journals Failure Mechanism Analysis and Support Technology for Roadway Tunnel in Fault Fracture Zone: A Case Study

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3767
Author(s):  
Kai Wang ◽  
Lianguo Wang ◽  
Bo Ren
Keyword(s):  
Failure Mechanism ◽  
Fracture Zone ◽  
Fractured Rock ◽  
Stress Test ◽  
Deformation Monitoring ◽  
Mechanism Analysis ◽  
Support Design ◽  
Geological Conditions ◽  
Fault Fracture Zone

This paper introduces a case study on the failure mechanism and support design of a roadway tunnel in the fault fracture zone of the 106 mining area in the Yuandian no.2 coal mine. Based on the on-site geological conditions (in-situ stress test, borehole television imaging, and lithological analysis), the failure mechanism of the roadway tunnel in the fault fracture zone was studied. The test results showed that the high tectonic stress, fractured rock, and poor lithology are the primary reasons for the roadway instability. According to the support principles of grouting reinforcement, pre-reinforced support, and rational support range, a new type of combined support technology was proposed, including advanced grouting, grouting bolts, and grouting anchor cables. A 100 m roadway section was selected for field testing using the new support scheme, and detailed deformation monitoring was performed. Monitoring results showed that the roadway deformation under the new support was significantly reduced. During the roadway excavation process, no roof collapse phenomenon occurred, and the safety of roadway excavation was ensured. This successful case provides an important reference for similar roadway projects in the fault fracture zone.

scholarly journals Failure Mechanism Analysis and Support Design for Deep Composite Soft Rock Roadway: A Case Study of the Yangcheng Coal Mine in China

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Bangyou Jiang ◽  
Lianguo Wang ◽  
Yinlong Lu ◽  
Shitan Gu ◽  
Xiaokang Sun
Keyword(s):  
Failure Mechanism ◽  
Coal Mine ◽  
Failure Mechanisms ◽  
Soft Rock ◽  
Deformation Monitoring ◽  
Surrounding Rock ◽  
Support Design ◽  
Soft Rock Roadway ◽  
Rock Roadway

This paper presented a case study of the failure mechanisms and support design for deep composite soft rock roadway in the Yangcheng Coal Mine of China. Many experiments and field tests were performed to reveal the failure mechanisms of the roadway. It was found that the surrounding rock of the roadway was HJS complex soft rock that was characterized by poor rock quality, widespread development of joint fissures, and an unstable creep property. The major horizontal stress, which was almost perpendicular to the roadway, was 1.59 times larger than the vertical stress. The weak surrounding rock and high tectonic stress were the main internal causes of roadway instabilities, and the inadequate support was the external cause. Based on the failure mechanism, a new support design was proposed that consisted of bolting, cable, metal mesh, shotcrete, and grouting. A field experiment using the new design was performed in a roadway section approximately 100 m long. Detailed deformation monitoring was conducted in the experimental roadway sections and sections of the previous roadway. The monitoring results showed that deformations of the roadway with the new support design were reduced by 85–90% compared with those of the old design. This successful case provides an important reference for similar soft rock roadway projects.

scholarly journals Support System for Tunnelling in Squeezing Ground of Qingling-Daba Mountainous Area: A Case Study from Soft Rock Tunnels

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Xiuling Wang ◽  
Jinxing Lai ◽  
Rodney Sheldon Garnes ◽  
Yanbin Luo
Keyword(s):  
Support System ◽  
Strong Support ◽  
Mountainous Area ◽  
Squeezing Ground ◽  
Tunnel Face ◽  
Support Design ◽  
Tunnel Support ◽  
Geological Conditions ◽  
Rock Tunnels

Tunnelling or undertaking below-ground construction in squeezing ground can always present many engineering surprises, in which this complicated geology bring a series of tunnelling difficulties. Obviously, if the major affecting factors and mechanism of the structure damage in these complicated geological conditions are determined accurately, fewer problems will be faced during the tunnel excavation. For this study, reference is made to four tunnel cases located in the Qingling-Daba mountainous squeezing area that are dominated by a strong tectonic uplift and diversified geological structures. This paper establishes a strong support system suitable for a squeezing tunnel for the purpose of addressing problems exhibited in the extreme deformation of rock mass, structure crack, or even failure during excavation phase. This support system contains a number of temporary support measures used for ensuring the stability of tunnel face during tunnelling. The final support system was constructed, including some key techniques such as the employment of the foot reinforcement bolt (FRB), an overall strong support measure, and more reserved deformation. Results in this case study showed significant effectiveness of the support systems along with a safe and efficient construction process. The tunnel support system proposed in this paper can be helpful to support design and provide sufficient support and arrangement before tunnel construction in squeezing ground.

scholarly journals Tunnel Collapse Mechanism and Its Control Strategy in Fault Fracture Zone

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jin Zhang ◽  
Mengxue Wang ◽  
Chuanhao Xi
Keyword(s):  
Large Deformation ◽  
Deformation Mechanism ◽  
Fracture Zone ◽  
Theoretical Research ◽  
Collapse Mechanism ◽  
Control Effect ◽  
Geological Conditions ◽  
Fault Fracture Zone ◽  
Reinforcement Measures ◽  
And Control

Complex geological conditions such as fault fracture zone will have a significant adverse impact on tunnel engineering, and collapse, large deformation, and other problems are prominent. The research on the large deformation mechanism and control of tunnel crossing fault fracture zone can provide guidance for tunnel safety construction. Based on the Jingzhai tunnel, combined with geological analysis, theoretical research, numerical simulation, and other means, this paper studies and analyzes the large deformation mechanism of the tunnel. The control effect of different advanced reinforcement measures is studied.

scholarly journals A Water-Rock Coupled Model for Fault Water Inrush: A Case Study in Xiaochang Coal Mine, China

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Luyuan Wu ◽  
Haibo Bai ◽  
Chao Yuan ◽  
Guangming Wu ◽  
Changyu Xu ◽  
...  
Keyword(s):  
Fracture Zone ◽  
Permeability Coefficient ◽  
Axial Stress ◽  
Water Inrush ◽  
Coupled Model ◽  
Fault Zones ◽  
Fractured Zone ◽  
Fault Fracture Zone ◽  
Fractured Sandstone

Water inrush disasters in mining frequently occur under the influence of confined water-bearing fault zones. Therefore, investigating the fault water inrush mechanism is necessary to reduce the number of occurrences of this type of disaster. In fault zones, the rock is highly fractured, and the mechanism of water conduction is complex. In this research, the seepage mechanism of fractured sandstone in fault zones is studied through experiments, and the results indicate that the permeability coefficient of fractured sandstone depends on the axial stress and particle size. The relationship between the permeability coefficient and axial stress was an exponential relationship. Then, a water-rock coupled model is proposed based on the experimental results, which considers the different water flow patterns during water inrush disasters. Finally, a numerical simulation combined with the water-rock coupled model is conducted to investigate the fault water inrush mechanism of a case study, and the results reveal that when water inrush disasters occur during mining, two types of conditions are required. One is that the connection among the fractured zone of the coal seam roof, fault fracture zone, and aquifer fails, and the other is that the connection among the fractured zone of the water inrush prevention pillar, fault fracture zone, and aquifer fails. This study contributes to an increased understanding of the mechanism of water inrush disasters and the design of water inrush prevention pillars.

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

2011 ◽  
Vol 105-107 ◽  
pp. 1203-1210 ◽  
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.

The Construction Technology and Numerical Simulation on Tunnels Throughing Fault Fracture Zone with Rich Water

2012 ◽  
Vol 170-173 ◽  
pp. 3241-3244
Author(s):  
Bao Fu Duan ◽  
Ying Lei Zhu ◽  
Lei Li ◽  
Sheng Zhi Wu
Keyword(s):  
Numerical Simulation ◽  
Water Permeability ◽  
Fracture Zone ◽  
Water Resistance ◽  
Field Measurements ◽  
Construction Technology ◽  
Geological Conditions ◽  
Fault Fracture Zone ◽  
Construction Condition ◽  
Excavation Area

Fault fracture zone with rich water has some bad geological conditions such as low strength, deformation, strong water permeability, poor water resistance. Landslide has been happened because the water permeability. This paper is based on Yan-jia Tunnel in HuBei-Guzhu Highway. For the bad geological conditions, WSS is taken as the advanced support method to reinforce soil and stop watering. The method has improved the construction condition. To reduce the excavation area in one time and the disturbance to surrounding soil, the construction method of meshshotcreting firstly is adopted. The paper also do the numerical simulation with the numerical calculation tool of the software ABAQUS. The result is basically consistent with the field measurements, which has significance on the subsequent design and construction of underground projects with similar geological conditions

scholarly journals A Case Study on Large Deformation Failure Mechanism and Control Techniques for Soft Rock Roadways in Tectonic Stress Areas

2019 ◽  
Vol 11 (13) ◽  
pp. 3510 ◽  
Author(s):  
Xue ◽  
Gu ◽  
Fang ◽  
Wei
Keyword(s):  
Numerical Simulation ◽  
Large Deformation ◽  
Failure Mechanism ◽  
Support System ◽  
Soft Rock ◽  
Tectonic Stress ◽  
Geological Conditions ◽  
Soft Rock Roadway ◽  
Rock Roadway

Large deformation and failure of soft rock are pressing problems in the mining practice. This paper provides a case study on failure mechanisms and support approaches for a water-rich soft rock roadway in tectonic stress areas of the Wangzhuang coal mine, China. Mechanic properties of rock mass related to the roadway are calibrated via a geological strength index method (GSI), based on which a corresponding numerical simulation model is established in the Universal Discrete Element Code (UDEC) software. The failure mechanism of the roadway under water-saturating and weathering conditions is revealed by field tests and numerical simulation. It is found that the stress evolution and crack development are affected by weathering and horizontal tectonic stresses. The roadway roof and floor suffer from high stress concentration and continuous cracking, and are consequently seen with rock failure, strength weakening, and pressure relief. Unfortunately, the current support system fails to restrain rock weathering and strength weakening, and the roadway is found with serious floor heave, roof subsidence, and large asymmetric deformation. Accordingly, a new combined support system of “bolt–cable–mesh–shotcrete + grouting” is proposed. Moreover, numerical simulation and field testing are conducted to validate the feasibility and effectiveness of the proposed approach, the results of which demonstrate the capacity of the proposed new support method to perfectly control the surrounding rock. Findings of this research can provide valuable references for support engineering in the soft rock roadway under analogous geological conditions.

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