Ground stress and its impact on the stability of the surrounding rock in the Lüliang mining area

2011 ◽  
Vol 21 (5) ◽  
pp. 625-630 ◽  
Author(s):  
Lianguo Wang ◽  
Yinlong Lu
Keyword(s):  
Mining Area ◽  
Surrounding Rock ◽  
Ground Stress ◽  
The Stability

Numerical Simulation on Supporting of Deep Surrounding Rock with Zonal Disintegration Tendency

2013 ◽  
Vol 671-674 ◽  
pp. 230-234
Author(s):  
Yu Jun Zuo ◽  
De Kang Zhu ◽  
Wan Cheng Zhu
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Surrounding Rock ◽  
Zonal Disintegration ◽  
Finite Element Software ◽  
Stability Of Surrounding Rock ◽  
Ground Stress ◽  
Zonal Disintegration Phenomenon ◽  
The Stability ◽  
The Zonal Disintegration Phenomenon

In order to study the supporting of deep surrounding rock with zonal disintegration tendency, the zonal disintegration phenomenon of deep surrounding rock under three supporting forms is analyzed by the ABAQUS finite element software in this paper, and three supporting forms are un-supporting, bolting and grouting, and combined “Bolting and grouting plus Anchor rope” supporting. The results show that the different effects to zonal disintegration under different supporting forms will occur. Supporting can help to restrain the zonal disintegration of the reinforcement part advantageously, and also lower rupture degree of zonal disintegration and reduce the size of rupture zone. Meanwhile, the stability of surrounding rock is improved. But zonal disintegration may occur outside reinforcement part under greater ground stress. The results are great importance to a better understanding of the deep roadway supporting.

Experimental Analysis on Microstructure and Mineral Composition of Jurassic Soft Rock in Shajihai Mining Area of Xinjiang

2013 ◽  
Vol 353-356 ◽  
pp. 24-27
Author(s):  
Xiao Lei Wang ◽  
Shun Xi Yan ◽  
Hai Qiao Wen
Keyword(s):  
Mineral Composition ◽  
Soft Rock ◽  
Mining Area ◽  
Sem Analysis ◽  
Surrounding Rock ◽  
Test Results ◽  
X Ray Diffraction ◽  
Component Content ◽  
The Stability ◽  
Soft Rock Roadway

In order to find out themicroscopic structure and determine mineral composition and relative content ofroadway soft rock in Shajihai mining area, this paper carried out experimentsof scanning electron microscope (SEM) analysis and X-ray diffraction analysis.SEM test results show that the microstructure of the surrounding rock isgenerally poor and joint, crack, pore are developed. The crack is easy toexpand under the effect of surrounding rock pressure and water, which makesrock mass more broken and greatly reduces the stability of surrounding rock.X-ray diffraction analysis test shows that the component content of clayminerals in the surrounding rock is high. Clay mineral in mudstone containsmontmorillonite and content of illite/smectite mixed layer is relativelyhigher, up to 45%. In conclusion, soft rock roadway of Shajihai mine areabelongs to the typical swelling-jointed compound soft rock. The targeted andreasonable compound transformation technology and coupling support measuresmust be adopted when supporting.

scholarly journals Key Factors Identification and Risk Assessment for the Stability of Deep Surrounding Rock in Coal Roadway

2019 ◽  
Vol 16 (15) ◽  
pp. 2802 ◽  
Author(s):  
Dongmei Huang ◽  
Weijun Li ◽  
Xikun Chang ◽  
Yunliang Tan
Keyword(s):  
Risk Assessment ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Fuzzy Comprehensive Evaluation ◽  
Mining Area ◽  
Surrounding Rock ◽  
Risk Level ◽  
Affecting Factors ◽  
Key Factors ◽  
The Stability

In order to evaluate the stability of deep surrounding rock, all of the affecting factors should be theoretically identified. However, some factors have slight impacts on the stability of deep surrounding rock compared with others. To conduct an effective risk assessment, key factors should be first extracted. The analytic hierarchy process (AHP) and grey relation analysis (GRA) methods are integrated to determine the key factors. First, the AHP method is applied to sort the factors by calculating the weights of them. Seven out of fifteen factors are extracted as the key factors, which account for 80% of the weights. Further, the GCA method is used to validate the effects of these key factors by analyzing the correlation between the performance of each factor and that of the reference. Considering the influence of these key factors and experts’ judgements, the multilevel fuzzy comprehensive evaluation method is adopted to obtain the risk level of the deep surrounding rock stability. Finally, the risk assessment of the deep surrounding rock in the E-Zhuang coal mine of Chinese Xinwen Mining Area illustrates the operability of the proposed method.

Surrounding Rock Classification in Deep Roadway of Coal Mine

2011 ◽  
Vol 181-182 ◽  
pp. 242-246 ◽  
Author(s):  
Bin Liu ◽  
Quan Sheng Liu
Keyword(s):  
Coal Mine ◽  
Surrounding Rock ◽  
Support Design ◽  
Geological Investigation ◽  
Rock Classification ◽  
Rock Stability ◽  
Mining Depth ◽  
Deep Rock ◽  
Ground Stress ◽  
The Stability

With the increase of mining depth，most coals in China have been deep mining stage. Compared to the shallow roadway, the characteristics of deformation-failure of surrounding rock show significant differences in the deep roadway, and the deep rock features of the surrounding rock are not considered in the traditional classification of roadway. So it is needed that systematical study on the surrounding rock classification for the stability evaluation of the deep roadway to meet the demand of the support design and the construction of the deep roadway in coal mine of China. The paper puts forward classification system of surrounding rock in deep roadway of coal mine according to on-the-spot geological investigation, rock ultrasonic testing, in-situ ground stress testing and comprehensive analysis on the surrounding rock stability of deep roadway in typical ore area.

scholarly journals Partitioning Control Mechanism and Engineering Practice of Rebuilding Bearing Arch in Surrounding Rock under High Ground Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Mengtang Xu ◽  
Ke Li ◽  
Youlin Xu
Keyword(s):  
Performance Test ◽  
Control Mechanism ◽  
Mechanical Performance ◽  
Surrounding Rock ◽  
General Idea ◽  
Engineering Practice ◽  
Load Bearing ◽  
Load Increase ◽  
Ground Stress ◽  
The Stability

The mining of coal seam has a significant influence on the stability of the roadway near it, especially under the condition of high ground stress. To study the control mechanism of the surrounding rock under the influence of high ground stress, a general idea for the partition control of the rebuilding bearing arch (RBA) was proposed in this paper. Based on the basic mechanical performance test of the bearing arch, this paper built a mechanical model of the RBA based on Protodyakonov’s pressure arch theory, analyzed the influence of the strength of the bearing arch on the surrounding rock failure, and obtained the ultimate thickness of the bearing arch failure under high ground stress. The results show that the RBA’s damage is closely related to the overburden load and RBA’s thickness. The tensile stress and shear stress of RBA increase linearly with the overburden load increase and increase sharply with the load-bearing arch’s thickness, showing a nonlinear relationship. To maintain the surrounding rock’s stability, it is necessary to ensure that the RBA’s thickness is within a specific range. The results are applied to the Wantian coal mine. The theoretically determined load-bearing thickness is 10 m, which can effectively control the surrounding rock deformation and significantly reduce the roadway’s repair rate.

scholarly journals Plastic Failure Analysis of Roadway Floor Surrounding Rocks Based on Unified Strength Theory

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Wenxiang Zheng ◽  
Qingwei Bu ◽  
Yaoqing Hu
Keyword(s):  
Spatial Relationship ◽  
Mining Area ◽  
Surrounding Rock ◽  
Strength Theory ◽  
Rock Body ◽  
Unified Strength Theory ◽  
Plastic Failure ◽  
In Situ Stresses ◽  
The Stability

Taking the whole surrounding rock of an excavation roadway as the research object, the elastoplastic failure mechanics analysis of the surrounding rock body of the excavated roadway under three-directional in situ stresses is carried out by using the knowledge of generalized plane strain problems and unified strength theory, and the equations are derived for the elastic-plastic zone stress together with the plastic fracture range of the roadway floor surrounding rock under three-directional in situ stresses. At the same time, by means of the conclusion of mechanical analysis and the results of in situ detection of in situ stress in the Changcun mining area, the stability of the roadway floor surrounding rock was analyzed. The analysis reveals the influence on the stability of the roadway floor surrounding rock between the spatial relationship with the different in situ stresses and the roadway layout; meanwhile, it calculates the range of the plastic failure zone and the stress value of the #1 roadway floor in the S6 mining area of Changcun mine, which provides a reliable theoretical mechanical reference for research on roadway floor heave control technology.

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 Analysis of Tunnel Water Inrush Considering the Influence of Surrounding Rock Permeability Coefficient by Excavation Disturbance and Ground Stress

2021 ◽  
Vol 11 (8) ◽  
pp. 3645
Author(s):  
Helin Fu ◽  
Pengtao An ◽  
Long Chen ◽  
Guowen Cheng ◽  
Jie Li ◽  
...  
Keyword(s):  
Permeability Coefficient ◽  
Water Pressure ◽  
Water Inrush ◽  
Surrounding Rock ◽  
Water Inflow ◽  
Calculation Error ◽  
External Water Pressure ◽  
Ground Stress ◽  
External Water ◽  
Inflow Prediction

Affected by the coupling of excavation disturbance and ground stress, the heterogeneity of surrounding rock is very common. Presently, treating the permeability coefficient as a fixed value will reduce the prediction accuracy of the water inflow and the external water pressure of the structure, leading to distortion of the prediction results. Aiming at this problem, this paper calculates and analyzes tunnel water inflow when considering the heterogeneity of permeability coefficient of surrounding rock using a theoretical analysis method, and compares with field data, and verifies the rationality of the formula. The research shows that, when the influence of excavation disturbance and ground stress on the permeability coefficient of surrounding rock is ignored, the calculated value of the external water force of the tunnel structure is too small, and the durability and stability of the tunnel are reduced, which is detrimental to the safety of the structure. Considering the heterogeneity of surrounding rock, the calculation error of water inflow can be reduced from 27.3% to 13.2%, which improves the accuracy of water inflow prediction to a certain extent.

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.

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.

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