Field Investigation on the Stability of the Tunnel Surrounding Rock and the Support Measures under TBM Construction

2012 ◽  
Vol 446-449 ◽  
pp. 2182-2185
Author(s):  
Yu Suo Wang ◽  
Ming Nian Wang ◽  
Zheng Qun Wu ◽  
Qi Xin Yang
Keyword(s):  
Field Investigation ◽  
Surrounding Rock ◽  
Support Measures ◽  
The Stability

Field Investigation on the Stability of the Tunnel Surrounding Rock and the Support Measures under TBM Construction

2012 ◽  
Vol 446-449 ◽  
pp. 2182-2185
Author(s):  
Yu Suo Wang ◽  
Ming Nian Wang ◽  
Zheng Qun Wu ◽  
Qi Xin Yang
Keyword(s):  
Stability Condition ◽  
Field Investigation ◽  
Surrounding Rock ◽  
Support Measures ◽  
The Stability

Considering the effect on surrounding rock exerted by TBM construction and its corresponding support measures are quite different from those of drilling and blasting construction, this study attempts to investigate the disturbance of TBM construction and its countermeasures. The investigation specifies the size of the drop pieces, position and cause and provides support measures for different stability condition of surrounding rock.

scholarly journals Study on the Fracture Distribution Law and the Influence of Discrete Fractures on the Stability of Roadway Surrounding Rock in the Sanshandao Coastal Gold Mine, China

2019 ◽  
Vol 11 (10) ◽  
pp. 2758
Author(s):  
Gang Liu ◽  
Fengshan Ma ◽  
Haijun Zhao ◽  
Guang Li ◽  
Jiayuan Cao ◽  
...  
Keyword(s):  
Field Investigation ◽  
Surrounding Rock ◽  
Gold Mine ◽  
Rock Masses ◽  
Distribution Law ◽  
Deformation And Failure ◽  
Roadway Stability ◽  
The Stability ◽  
Fracture Distribution ◽  
Matlab Programming

Cracks are critical for the deformation and failure of rock masses, but the effects of real cracks are rarely considered when evaluating the stability and safety of practical engineering. This paper presents a study on the application of fractures in the Sanshandao Gold Mine. Field investigation and statistical analysis methods were adopted to obtain the distribution laws of the cracks. Laboratory tests, MATLAB programming, and simulation using the software, GDEM (Gdem Technology, Beijing, China, Co., Ltd.), were employed to study the mechanical behaviors of rock masses with real fractures after excavation. The main results are as follows: (1) Three sets of highly discrete cracks were developed in the study area. Their inclination and dip can be approximately considered to follow a Gaussian distribution or uniform distribution. They had close ties to the three faults developed in the mining area. (2) Compared with the model that did not consider cracks and the model processed by the equivalence idea, the surrounding rock deformation caused by excavation of the model that considered real cracks was larger than that of the former and smaller than that of the latter. However, its influence range was larger than that of the other two models. The results show that it is reasonable to use three sets of discrete cracks to characterize the fracture distribution of the surrounding rock. In the evaluation of roadway stability, it is not advisable to use the equivalence method to deal with all the cracks. Considering a part of the cracks that are compatible with the size of the calculation model, a relatively accurate evaluation can be obtained in terms of the deformation, failure, and permeability changes of the surrounding rock.

scholarly journals Deformation Mechanism and Control Technology of Surrounding Rock in the Deep-Buried Large-Span Chamber

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-22
Author(s):  
Weijian Yu ◽  
Ke Li
Keyword(s):  
Field Investigation ◽  
Surrounding Rock ◽  
Engineering Practice ◽  
Underground Engineering ◽  
Metal Mesh ◽  
Severe Problem ◽  
Factors Affecting ◽  
Large Span ◽  
Anchor Cable ◽  
The Stability

The selection of the support scheme for deep-buried and large-span chambers has been a severe problem in underground engineering. To further study the mechanical mechanism of large deformation, based on the repair engineering of the chambers of Pingdingshan No.6 mine in China, the field investigation, laboratory test, numerical simulation, and theoretical analysis were studied. The surrounding rock of the central substation chamber (CSC) and the main pumping chamber (MPC) were classified according to the rock mass rating (RMR) classification method, and the main factors affecting the stability of the surrounding rock of the chambers were revealed. A prediction model of mechanical parameters of the surrounding rock was established based on the Hoek-Brown failure criterion. Additionally, the prediction results were used in FLAC3D to further analyze the failure of the original support scheme, and the feasibility of the restoration plan was proposed. Six key points of support technology for this kind of chamber were put forward. Comprehensive support and repair scheme, including “bolt, metal mesh, shotcrete, grouting, anchor cable, and combined anchor cable,” was put forward. The engineering practice indicated that the deformation rate was less than 0.7 mm/d, which was beneficial to the long-term stability of CSC and MPC. The implementation of this restoration project can provide a reference for other similar projects.

scholarly journals Influence of Loose Contact between Tunnel Lining and Surrounding Rock on the Safety of the Tunnel Structure

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1733
Author(s):  
Zijian Ye ◽  
Chengping Zhang
Keyword(s):  
Contact Area ◽  
Three Dimensional ◽  
Field Investigation ◽  
Surrounding Rock ◽  
Tunnel Lining ◽  
Point Of View ◽  
Railway Tunnel ◽  
Contact State ◽  
Lining Structure ◽  
The Stability

The improvement of the contact state between the surrounding rock and tunnel lining, such as the effect of back-fill grouting behind lining, was important for maintaining the stability of the lining structure. To explore the influence of loose contact states behind lining on the safety of tunnel lining, a case of field investigation in a railway tunnel with a symmetrical lining structure was presented in this paper. A model test was conducted to prove the accuracy of the numerical simulation in the condition of dense contact state between the lining and surrounding rocks. Based on this, the three-dimensional (3-D) impact of loose contact states on the mechanic behavior of the lining structure under different compactness and different loose contact areas behind lining was investigated and summarized. Furthermore, the influence of the percentage of the insufficient strength behind lining was explored. Finally, the grade of the influence of the loose contact state on the safety of the lining structure was classified. The results revealed that: (1) in order to maintain the stability of lining structure, the compactness of the back-fill grouting behind lining was recommended to be above 80%, and the range of the loose contact area should be no more than 60 degree; (2) the strength of the back-fill grouting behind lining should be above 50% strength of the surrounding rock, the loose contact state behind lining should be improved in time to avoid expansion of the loose contact area; and (3) the classification of the influence grade on the safety of the lining structure provides a basic reference for controlling the quality of the back-fill grouting. This research gives a new point of view for the evaluation of the contact state between lining and surrounding rock.

scholarly journals Study on Safety Control of Large-Section Roadway with High Stress and Broken Surrounding Rock

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Wen-qing Peng ◽  
Hao Zhu ◽  
Qi Wang ◽  
Gang Peng
Keyword(s):  
High Stress ◽  
Field Investigation ◽  
Surrounding Rock ◽  
Jiangxi Province ◽  
Engineering Practice ◽  
Large Section ◽  
Middle Point ◽  
Safety Control ◽  
Anchor Cable ◽  
The Stability

In order to solve the problem of difficult support of the roadway with high stress and large-section broken surrounding rock, this paper takes the subinclined shaft in Gaokeng mine of Jiangxi Province as the engineering background, analyzes the deformation mechanism and support mode of the roadway under the influence of mining through field investigation and mechanical derivation, and concludes that the stress concentration point of the roadway is in the middle point of roof and floor and the middle point of left and right sides. Through the modeling analysis of FLAC3D numerical software and the comparison of various support schemes, it is concluded that, after the combined support method of “anchor, net, and spray + grouting + full-section anchor cable + floor anchor cable“ is adopted, the convergence of roof and floor is reduced by 508 mm, and the convergence of two sides is reduced by 663 mm. And, it is applied in engineering practice. The results show that the combined support scheme can effectively control the stability of the surrounding rock.

scholarly journals Research on the Deformation and Control Technology of Surrounding Rock in Entry Retaining along the Gob Side

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Meng Zhang ◽  
Hui He ◽  
Yu Zhang ◽  
Xin Jin ◽  
Xinyu Liang ◽  
...  
Keyword(s):  
Mining Area ◽  
Field Investigation ◽  
Industrial Test ◽  
Surrounding Rock ◽  
Control Technology ◽  
Coal Reserve ◽  
Working Face ◽  
Pillar Mining ◽  
Mining Pressure ◽  
The Stability

This paper studies and introduces the successful case of gob-side entry retaining technology and the typical mining pressure law in Luan mining area, which is the main mining coal seam in Qinshui coalfield. Qinshui coalfield has an estimated coal reserve of 300 billion tons, accounting for 9.58% of the total national coal reserve in China, especially anthracite, chemical coal, and coking coal. The methods of field investigation, theoretical analysis, physical experiment, and industrial test are adopted. Through the field investigation, theoretical analysis, physical experiments, and industrial test, the following conclusions have been drawn in this study: (1) A thorough engineering geological investigation was conducted on the entry retaining along the gob side on noncoal pillar mining working face, which covers multiple periods of mining process including the roadway excavation period, primary mining period, primary mining stability period, and secondary mining influence period. A series of analysis and tests were conducted such as core sampling, rock mechanics property testing, borehole detection, and flexible formwork support evaluation, which laid a foundation for identifying the mining pressure law of gob-side entry retaining by using noncoal pillar mining. (2) The mining pressure law was studied through the collection of the field measurements taken from the entry retaining along the gob side on noncoal pillar mining working face. The keys to achieve the roadway surrounding rock stability through noncoal pillar mining are obtained. According to the study, the stability control of retained roadway surrounding rock mainly depends on the stability of top coal, coal side, and shoulder angle coal. (3) In this study, a roadway reinforcement scheme is proposed to improve the surrounding rock control technology for gob-side entry retaining by noncoal pillar mining, whose effectiveness has been verified by a series of industrial test. Therefore, the wide adoption of the noncoal pillar mining method in Number #3 coal mine can significantly relieve the predicament of coal pressing under a large number of buildings in Luan mining area, which provides insightful guidance to the coal-free pillar mining in the whole Luan mining area.

scholarly journals Study on instability failure mode and monitoring early warning standard of surrounding rock in fully weathered argillaceous sandstone section of large section tunnel

2019 ◽  
Vol 136 ◽  
pp. 04023
Author(s):  
Ming Zhao ◽  
Ke Li ◽  
Hong Yan Guo ◽  
KaiCheng Hua
Keyword(s):  
Limit State ◽  
Stable State ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Large Section ◽  
Rock Stability ◽  
Geological Conditions ◽  
Construction Step ◽  
The Face ◽  
The Stability

Based on the special geological conditions of a tunnel in Qingyuan section of Huizhou-Zhanzhou Expressway, FLAC3d numerical simulation software is used to simulate the rheological properties and instability of surrounding rock in large-section fully weathered sandstone section, and the stability and loss of surrounding rock are analyzed. The deformation of the dome and the face at steady state is analyzed. It is found that: 1) when the surrounding rock is in a stable state, the deformation curve of the dome is smooth. When the surrounding rock of the face is unstable, the front of the face appears ahead. Deformation should be first strengthened on the surrounding rock in front of the face. 2) The arched foot is an important part of the instability of the surrounding rock. In order to prevent the expansion of the collapsed part, the arched part should be reinforced. 3) In order to obtain the limit state of surrounding rock stability, the strength of surrounding rock is reduced, and the strength reduction coefficient corresponding to the displacement sudden point is taken as the safety factor of rock stability around the hole, and the stability safety coefficients of surrounding rock of each construction step are greater than 1.2. 4) The dynamic standard values of deformation control in the whole construction stage are obtained by analyzing the deformation curves of each data monitoring point with time in the corresponding time period of each construction step.

Study on the Truss Support Technology for Coal Side in a Soft Broken Coal Roadway Under High Stress

2012 ◽  
Vol 524-527 ◽  
pp. 360-363
Author(s):  
Shou Yi Dong ◽  
Qi Tao Duan ◽  
Fu Lian He ◽  
Qi Li ◽  
Hong Jun Jiang
Keyword(s):  
Production Condition ◽  
High Stress ◽  
Field Investigation ◽  
Surrounding Rock ◽  
Theory Analysis ◽  
Large Section ◽  
Cable Channel ◽  
Coal Roadway ◽  
Measurement Results ◽  
Steel Truss

The coal side deformation and sliding can not be effectively controlled by use of the traditional bolt or cable support in the high stress crushed surrounding rock and large section roadway. For solving this problem, the new prestressed truss support technology is put forward, and its supporting principles of roof and two walls are stated. The mechanical model of cable-channel steel truss is established, and then the tensile strength of the cable and the maximum deflection of the channel steel are derived. By way of field investigation, mechanics theory analysis and actual production condition, the scheme is defined and applied in the replacement roadway. Measurement results of surrounding rock behavior show that the coal side displacement is no more than 254mm and the roof convergence is less than 172mm. Apparent economic and technical profits have been achieved.

Nondestructive Test on Typical Roadway Supports of a Mine via Drilling Core and Ground Penetrating Radar

2011 ◽  
Vol 368-373 ◽  
pp. 2411-2416
Author(s):  
Jian Ping Han ◽  
Hai Peng Liu
Keyword(s):  
Ground Penetrating Radar ◽  
Geological Structure ◽  
Surrounding Rock ◽  
Potential Threat ◽  
Real Performance ◽  
Design Requirements ◽  
And Performance ◽  
The Stability ◽  
Ground Penetrating ◽  
Drilling Core

Temporary or permanent supports are necessary in underground construction for maintaining the stability and limiting the damage of surrounding rock. Due to the uncertainty of geological structure, the specificity of the underground environment as well as other factors, the quality and performance of supporting structure are often difficult to satisfy the design requirements, which not only seriously affects the normal construction and operation of mines but also has the potential threat to the safety of underground production. In order to investigate the influence of the unfavorable geologic environment on supporting concrete and evaluate the real performance of roadway supports of a mine, 17 typical projects were chosen and the strength of supporting concrete was detected by nondestructive drilling core method. The result shows that the strength is widely less than the design value. Furthermore, 4 projects of them were investigated by the ground penetrating radar (GPR) in order to evaluate the feasibility of GPR in the performance investigation of the roadway supports of a mine. The results indicate that ground penetrating radar is capable of measuring the thickness of the support, the distribution of rebars and the defects of the surrounding rock.

Hydro-Mechanical Coupled Analysis of the Stability of Surrounding Rock Mass of Underground Water-Sealed Oil Storage

2013 ◽  
Vol 405-408 ◽  
pp. 402-405 ◽  
Author(s):  
Yun Jie Zhang ◽  
Tao Xu ◽  
Qiang Xu ◽  
Lin Bu
Keyword(s):  
Rock Mass ◽  
Underground Water ◽  
Surrounding Rock ◽  
Comsol Multiphysics ◽  
Coupled Analysis ◽  
Coupling Theory ◽  
Oil Storage ◽  
Stability Of Surrounding Rock ◽  
Straight Wall ◽  
The Stability

Based on the fluid-solid coupling theory, we study the stability of surrounding rock mass around underground oil storage in Huangdao, Shandong province, analyze the stress of the surrounding rock mass around three chambers and the displacement change of several key monitoring points after excavation and evaluate the stability of surrounding rock mass using COMSOL Multiphysics software. Research results show that the stress at both sides of the straight wall of cavern increases, especially obvious stress concentration forms at the corners of the cavern, and the surrounding rock mass moves towards the cavern after excavation. The stress and displacement of the surrounding rock mass will increase accordingly after setting the water curtains, but the change does not have a substantive impact on the stability of surrounding rock mass.

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