scholarly journals Study on Rib Sloughage Prevention Based on Geological Structure Exploration and Deep Borehole Grouting in Front Abutment Zones

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Cheng Wang ◽  
Zuqiang Xiong ◽  
Chun Wang ◽  
Yuli Wang ◽  
Yaohui Zhang
Keyword(s):  
Coal Seam ◽  
Tectonic Stress ◽  
Geological Structure ◽  
Longwall Face ◽  
Mine Safety ◽  
Shanxi Province ◽  
Thick Coal Seam ◽  
Plastic Failure ◽  
Mining Conditions ◽  
Roof Strata

This research presents the grouting method of preventing rib sloughage which severely impacts mine safety and longwall retreat speed in thick coal seam with numerical simulation and laboratory tests. Based on the analysis of the plastic failure mode of five types of coal seam, roof strata ahead of the longwall face, and fractures developed in the coal seam, the following results are drawn, the range and degree of plastic failure generated in the coal seam and roof strata ahead of the longwall face gradually decreased as the coal mass strength increased; the grouting boreholes are essentially laid out within the coal rib instead of the roof. For a particular case of a coal mine in Shanxi province, a novel cement-based material was grouted, which fulfilled the reinforcement requirements under the tectonic stress regions and front abutment zones. Besides, the grouting borehole construction requested predrilled boreholes, full borehole intubation, lengthened hole sealing, and multiple-step drilling and grouting. This study can provide a theoretical framework of a design overview and practical basis for similar mining conditions in other coalfields.

Study on Overburden Strata Rupture Development Height Rules in Repeated Mining of Thick Coal Seams

2012 ◽  
Vol 170-173 ◽  
pp. 279-282
Author(s):  
Nan Nan Zhao ◽  
Yong Jie Yang ◽  
Chang Qing Wang
Keyword(s):  
Coal Seam ◽  
Field Measurement ◽  
Development Time ◽  
Lower Layer ◽  
Coal Seams ◽  
Thick Coal Seam ◽  
Upper Limit ◽  
Mining Conditions ◽  
Overburden Strata

Take 3 coal repeated mining of Luxi colliery as research background, overburden strata rupture development rules in repeated mining of thick coal seam were studied by using the methods of field measurement. The results indicate that the height of overburden crack belt reduced along with the increase of goaf development time; the crack belt height of upper layer is 34.73m, the ratio of crack height and mining thickness is 15.1, the crack belt height of lower layer increased to 41.51m, but the increased trend declined, the ratio is only 12.14, the development height after up-layer was excavated is 83.6% of the height after two coalface were excavated. The results have important guiding sense for predicting overburden rupture rules in the similar mining conditions and improving the upper limit.

scholarly journals Research on Mechanisms and Control Measures of Surrounding Rock Disaster in Large Section Roadway with Top Coal under the Influence of Tectonic Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Yang Yu ◽  
Jianfei Lu ◽  
Dingchao Chen ◽  
Yuxin Pan ◽  
Xiangqian Zhao ◽  
...  
Keyword(s):  
Damage Mechanics ◽  
Tectonic Stress ◽  
Surrounding Rock ◽  
Control Measures ◽  
Shanxi Province ◽  
Stress Effect ◽  
Large Section ◽  
Thick Coal Seam ◽  
Surrounding Rock Control ◽  
Seam Mining

Based on the research background of large section roadway with top coal (LSRTC) in thick coal seam mining in Wangzhuang Coal Mine, Shanxi Province, China, catastrophe characteristics of the surrounding rock of the LSRTC were investigated and summarized. Based on the principle of damage mechanics, the critical size discriminant of the LSRTC was deduced, and the induction mechanism of section size effect and tectonic stress effect on the roadway surrounding rock disaster was revealed. Accordingly, the roadway surrounding rock control principle with the basic idea of “stabilizing and controlling top coal, reconstructing the coal wall, and limiting floor heave” was put forward, and the roadway surrounding rock stability control countermeasures with the core technology of “strong pressure support for roof + grouting reinforcement for two sides + bolt barrier for floor angle” were developed, which solved the surrounding rock control problem of the LSRTC under the action of tectonic stress and provided a useful reference for the difficult problem of roadway surrounding rock control under similar conditions.

scholarly journals Investigation on coal seam distribution and gas occurrence law in Guizhou, China

2018 ◽  
Vol 36 (5) ◽  
pp. 1310-1334 ◽  
Author(s):  
Qingsong Li ◽  
Xin He ◽  
Jiahao Wu ◽  
Shu Ma
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Sedimentary Environment ◽  
Influence Factors ◽  
Preventive Treatment ◽  
Geological Structure ◽  
Mine Safety ◽  
Gas Content ◽  
Gas Occurrence ◽  
Safety Production

In order to enhance the management level of coal mine safety production and promote the “safe, accurate and efficient” preventive treatments for gas in Guizhou of China, the occurrence and other prominent features of coal and gas are investigated. The characteristics and regularities of coal mine accidents in Guizhou during 2001–2015 are summarized to analyze the commonness of gas accidents in general and determine the characteristics of gas preventive treatment. Geological data, gas basic parameters, and physical properties of coal of 386 mines and 761 sets of coal seams in Guizhou are also statistically analyzed. Based on step control theory of gas occurrence structure and the regionally tectonic regularity of coal-bearing stratum distribution, the deformations of coal measures in Guizhou mine area are mainly caused by great variation of stratigraphic occurrence, complicated geological structure, and high crustal stress. The regional occurrence of coal seam is obvious with the highest content of Tongzi–Zunyi–Liuzhi–Xingyi line, which gradually reduces to the both east and west sides. Influence factors and weights of gas occurrence are expounded from geological and coal factor by mathematical statistics, and the main influence factors of gas occurrence are the sedimentary environment, syncline structure, and metamorphic grade in proper sequence. Combined with the risk prediction of coal and gas outburst area, the prediction of gas pressure by gas content is not suitable under the special occurrence conditions. The initial velocity of gas emission, the solidity coefficient, and the damage type in more than 77% of minable seams all exceed the critical value. This work provides guidance in improvement of the governance situation for gas control in Guizhou. The index prediction system which is suitable for mining conditions of special coal mines in Guizhou should be established.

Numerical Simulation and Analysis of Rock Burst Induced by Roof Movement

2014 ◽  
Vol 522-524 ◽  
pp. 1394-1398
Author(s):  
Tao Qin ◽  
Yong Li Liu ◽  
Chang Ji Dong ◽  
Ping Wang
Keyword(s):  
Numerical Simulation ◽  
Comparative Analysis ◽  
Coal Seam ◽  
Pressure Distribution ◽  
Coal Mine ◽  
Process Simulation ◽  
Hard Coal ◽  
Thick Coal Seam ◽  
Soft Coal ◽  
Mining Conditions

For composite thick seams have been incidents burst power disasters, and seriously affect the safety of the mine production.Based on the engineering background in coal mine, through the same mining conditions, stope mining process simulation which happens in single hard coal, soft coal and single composite thick Coal Seam of Island face were studied through comparative analysis by FLAC3D　numerical simulation technology. Tendency and trend of the pressure distribution results obtain through the comparative analysis . The research results has been applied in the actual coal mining.

Trend Surface Analysis Method Applied in Coal Seam Structure in ZhuJiaHe

2015 ◽  
Vol 744-746 ◽  
pp. 686-689
Author(s):  
Xi Cheng Xue ◽  
Zhi Qi Wang
Keyword(s):  
Coal Seam ◽  
Surface Analysis ◽  
Coal Mine ◽  
Geological Structure ◽  
Mine Safety ◽  
Analysis Method ◽  
Trend Surface Analysis ◽  
Trend Surface ◽  
Surface Analysis Method ◽  
The Impact

Due to the impact of multi-period structure in Zhujiahe coal,Mine structure complicated and Has caused a certain impact on coal mine safety production. article Randomly selected 30 from 170 borehole date in coal mine.This paper analyzes 1, 2, 3 times of trend surface on No. 5-2 coal seam floor elevation.exploring the trend surface analysis method research in mine geological structure regular.

scholarly journals Effect of roof movement on gas flow in an extremely thick coal seam under fully mechanized sublevel caving mining conditions

2019 ◽  
Vol 8 (3) ◽  
pp. 677-688
Author(s):  
Haijun Guo ◽  
Xianzhang Li ◽  
Hao Cui ◽  
Kaixuan Chen ◽  
Yuanyuan Zhang
Keyword(s):  
Coal Seam ◽  
Gas Flow ◽  
Thick Coal Seam ◽  
Sublevel Caving ◽  
Mining Conditions

scholarly journals Study on Intelligent Identification Method of Coal Pillar Stability in Fully Mechanized Caving Face of Thick Coal Seam

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 305 ◽  
Author(s):  
Jingjing Dai ◽  
Pengfei Shan ◽  
Qi Zhou
Keyword(s):  
Coal Seam ◽  
Simulation Experiment ◽  
Coal Pillar ◽  
Shanxi Province ◽  
Parameter Determination ◽  
Pillar Stability ◽  
Thick Coal Seam ◽  
Identification Method ◽  
Optimal Value ◽  
The Relationship

The combination of coal precise mining and information technology in the new century is one of the important directions for the future development of coal mining. Taking the fully mechanized top coal caving condition of a thick coal seam in the 90,101 working face of Baoshan Yujing Coal Mine in Shanyin City, Shanxi Province as an example, the intelligent identification method of section coal pillar stability was studied. The load transfer law of overlying strata in the upper part of coal pillar was analyzed, and the coal pillar values of each index were obtained by using an empirical formula, mean impact value-genetic algorithm-BP neural network (MIV-GA-BP) simulation experiment, and finite difference algorithm. The Delphi index evaluation system was used to calculate the optimal value of the coal pillar. The results showed that the non-contact cantilevered triangle on the two wings of the coal pillar in the goaf reduced the stress on the coal pillar; according to the width of the coal pillar at 10 m, 14 m, 16 m, and 20 m, combined with the relationship between the plastic zone and the core zone of coal pillar, and the relationship between the stress field and the ultimate strength of coal pillar, the numerical simulation value of the coal pillar was determined. The MIV (mean impact value) characteristics screened out the influencing factors of coal pillar width in the section near the horizontal fully mechanized top coal caving face order of importance; the relative error between the predicted value and the expected value of the MIV-GA-BP simulation experiment was less than 5%, which has good stability for the multi-factor nonlinear coupling prediction problem; and the optimal value of the coal pillar was 16.03 m by the intelligent identification method of the coal pillar. When the 16 m pillar was used, the surrounding rock deformation of the roadway was small, and the control effect was good. The research results provide a theoretical basis and reference for the parameter determination of similar projects.

scholarly journals Study on the Key Technology of Controlling the Instability of Deep High-Stress Coal and Rock Mass and Relieving the Danger

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zhijing Zhang ◽  
Jianghong Zuo ◽  
Dongji Lei
Keyword(s):  
Rock Mass ◽  
Coal Seam ◽  
Rock Fracture ◽  
Mine Safety ◽  
Detection Accuracy ◽  
Pressure Relief ◽  
Rock Body ◽  
Thick Coal Seam ◽  
Before And After ◽  
Relief Effect

In order to solve the problem of stress concentration and gas overrun in the process of uncovering high gas and thick coal seam, combined with the occurrence characteristics of coal seams in Wuyang Coal Mine, the measures of “hydraulic and mechanical cavity making + steel screen pipe + surrounding rock grouting” are adopted to establish a method for mutual verification of multiple effect test indexes of residual stress, residual gas content, coal seam moisture content, and microseismic signal characteristics, and the three-dimensional accurate analysis of the influence range of hydraulic cavitation is effectively realized. By comparing and analyzing the gas extraction amount, the surrounding borehole stress change and the microseismic monitoring signals before and after the application of hydraulic cavitation technology are studied. The results show the following. (1) The pressure relief effect of the hydraulic cavity on surrounding coal decreases with the increase of distance, and the pressure relief effect is most obvious at 1.0∼2.5 m, in the range of 2.5–3.5 m around the hydraulic drilling hole, the duration, rate, and amplitude of pressure relief are reduced compared with those in the range of less than 2.5 m, while in the range of more than 3.5 m, the effect of pressure relief is very weak. (2) During the period of hydraulic cavitation release hole, the radius of water supply to coal seam is within 1.5 m, which accounts for 79% of coal wall area. (3) It is also a process where the stress distribution in the coal and rock body needs to be rebalanced before and after hydraulic caverning, which is often accompanied by microfracture of coal and rock mass. The analysis shows that, before hydraulic caverning, the waveform of coal and rock fracture signal has a short duration, large amplitude, and obvious signal mutation, and the dominant frequency of the signal is about 250 Hz, with large total energy. After hydraulic caverning, the intensity of coal and rock fracture events is greatly reduced. The research results can effectively identify the influence range of hydraulic cavitation, improve the detection accuracy and efficiency of hydraulic cavitation range, effectively predict and warn the hidden danger of mine safety, and provide a reference for the work of similar mines.

scholarly journals Physical Experiment and Numerical Modeling on the Failure Mechanism of Gob-Side Entry Driven in Thick Coal Seam

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5425 ◽  
Author(s):  
Xinshuai Shi ◽  
Hongwen Jing ◽  
Zhenlong Zhao ◽  
Yuan Gao ◽  
Yuanchao Zhang ◽  
...  
Keyword(s):  
Coal Seam ◽  
Failure Mechanism ◽  
Coal Pillar ◽  
Stability Control ◽  
Shear Cracks ◽  
Thick Coal Seam ◽  
Physical Model Tests ◽  
The Stability ◽  
Roof Strata ◽  
Overlying Strata

In this paper, a combination of physical model tests and numerical simulations were carried out to explore the overlying strata movement laws, failure mechanism, and cracks evolution of the gob-side entry driven in a thick coal seam. The physical experimental results indicated that the hanging cantilever beam was easily developed above the coal pillar after mining out the 2101 panel, resulting in a larger and stronger stress concentration. The overburden loads acting on the coal pillar can be greatly released after the hanging roof strata were cut down with an 18 m cutting line. Additionally, we adopted Universal Discrete Element Code (UDEC) software to investigate the deformation and crack evolution mechanism of the gob-side entry under different conditions. The primary-supported roadway underwent severe deformation, filling with a great quantity of tensile and shear cracks to the inner coal pillar. Both the physical and numerical results proved that the optimized-support parameters combined with roof-cutting measures could effectively guarantee the stability of the gob-side entry. This research can provide valuable guidance for the stability control of the gob-side entry in mines under similar conditions.

Sign in / Sign up

Export Citation Format

Share Document