scholarly journals Roadway Support in Deep “Three-Soft” Coal Seam: A Case Study in Yili Mining Area, China

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Wenxin Li ◽  
Jinxiao Liu ◽  
Lianjun Chen ◽  
Zhilu Zhong ◽  
Yongle Liu
Keyword(s):  
Coal Seam ◽  
Large Deformation ◽  
Mechanical Test ◽  
Mining Area ◽  
Surrounding Rock ◽  
Rock Properties ◽  
Support Design ◽  
Soft Coal ◽  
Secondary Support ◽  
Soft Coal Seam

This paper analyzes the large deformation of roadway in three-soft coal seam under the influence of tectonic stress. Taking the auxiliary conveying uphill roadway in Yili No. 1 Coal Mine as the engineering background, the deformation and failure mechanism of the surrounding rock and the supporting technology were studied. First, the characteristics of stress field and the surrounding rock properties of deep mining area were investigated through geostress measurement and rock mechanical test. Then, the roadway deformation and the loose circle of the supporting structure were obtained. Based on the results from measurement and theoretical analysis, we proposed a concept, i.e., “Stress adjustment-Strengthening-Grouting-Secondary support.” A numerical model was established to analyze the stress distribution and the state of plasticity in the surrounding rock. According to the results of the geostress measurement and the numerical simulation, a combined support scheme was proposed, i.e., “Yielding bolt & Shotcreting” as the primary support and “Prestressed grouting anchor cable & U-shaped shed” as the secondary support. Finally, the underground practice showed that the proposed support scheme can effectively control the large deformation and maintain the long-term stability of the roadway in deep and three-soft coal seam. The proposed technology has guiding significance for the support design under similar mining conditions.

Experimental Study on Mechanical Properties of Jurassic Soft Rock in Shajihai Mining Area of Xinjiang

2013 ◽  
Vol 353-356 ◽  
pp. 20-23
Author(s):  
Xiao Lei Wang ◽  
Shun Xi Yan ◽  
Guang Can Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Compression Test ◽  
Mechanical Test ◽  
Triaxial Compression ◽  
Soft Rock ◽  
Mining Area ◽  
Surrounding Rock ◽  
Test Results ◽  
Support Design

According to the problemsof serious deformation of soft rock roadways and lack of system andcomprehensive study on surrounding rock characteristics and failure mechanismin Shajihai mining area, this paper carried out a series of mechanicalexperiments on the characteristics of surrounding rock in this area includinguniaxial compression test, triaxial compression test and water absorption propertiestest. Mechanical test results show that the compressive strength of surroundingrock of roadway is generally low, and mudstone compressive strength is thelargest which is 19.23 MPa, and compressive strength of the minimum is coalwhich is 11.32 MPa under natural condition. However sandstone and mudstone’sability of water absorbing is strong, and coal saturation strength issignificantly greater than that of mudstone and sandstone. Therefore, we shouldmake full use of the strength of coal in roadway layout and support design.

scholarly journals Surrounding rock deformation control of asymmetrical roadway in deep three-soft coal seam: a case study

2018 ◽  
Vol 15 (5) ◽  
pp. 1917-1928 ◽  
Author(s):  
Wei Zhang ◽  
Ziming He ◽  
Dongsheng Zhang ◽  
Dahong Qi ◽  
Weisheng Zhang
Keyword(s):  
Coal Seam ◽  
Surrounding Rock ◽  
Rock Deformation ◽  
Deformation Control ◽  
Soft Coal ◽  
Soft Coal Seam ◽  
Surrounding Rock Deformation

scholarly journals Roadway supporting technology applied to three soft coal seam at Yanlong mining area in China

2019 ◽  
Vol 23 (Suppl. 3) ◽  
pp. 887-895
Author(s):  
Sheng Zhang ◽  
Jie Li ◽  
Jianhong Ma
Keyword(s):  
Coal Seam ◽  
High Stress ◽  
Mining Area ◽  
Deformation Characteristics ◽  
Uniform Load ◽  
Pressure Relief ◽  
Soft Coal ◽  
Coal Roadway ◽  
Soft Coal Seam ◽  
Drill Holes

The compressive strength of coal in Yanlong mine area of China is less than 3 MPa. Basically, it is powdery. The roof and floor rocks are mudstone. Therefore, this coal seam is a typical ?three soft? coal seam. Anchor and cable cannot be used due to low anchoring force. This paper describes how to support this type of soft coal roadway. The deformation characteristics of soft coal roadway were investigated. Results show the conventional U-shaped steel support is not subjected to uniform load, which bearing capacity can be improved by structural compensation, such as addition of horizontal and vertical beams made of U-shaped steel. In addition, by drilling pressure-relief holes in the ribs of a soft coal roadway, the stress distribution of surround rock in the roadway can be improved, which can transfer the high stress in the surrounding rock to deeper parts and reduce the pressure on the artificial support. A support method is to combine the strengthened U-shaped steel support with pressure-relieving drill holes, providing an economic and efficient way to support the very soft coal roadways.

scholarly journals The Complex Function Method Roadway Section Design of the Soft Coal Seam

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
Shihao Tu ◽  
Zhaoxin Li ◽  
Zhiwei Ye ◽  
Cun Zhang ◽  
Lei Zhang
Keyword(s):  
Coal Seam ◽  
Function Method ◽  
Vertical Wall ◽  
Complex Function ◽  
Surrounding Rock ◽  
Type Steel ◽  
Soft Coal ◽  
Distribution Laws ◽  
Soft Coal Seam ◽  
Complex Function Method

As for the sophisticated advanced support technique of vertical wall semicircle arch roadway in the three-soft coal seam, a design of flat top U-shape roadway section was put forward. Based on the complex function method, the surrounding rock displacement and stress distribution laws both of vertical wall semicircle arch roadway and of flat top U-shape roadway were obtained. The results showed that the displacement distribution laws in the edge of roadway surrounding rock were similar between the two different roadways and the area of plasticity proportion of flat top U-shape roadway approximately equals that of vertical wall semicircle arch roadway. Based on finite element method, the bearing behaviors of the U-type steel support under the interaction of surrounding rock in vertical wall semicircle arch roadway and flat top U-shape roadway were analyzed. The results showed that, from a mechanics perspective, U-type steel support can fulfill the requirement of surrounding rock supporting in flat top U-shape roadway and vertical wall semicircle arch roadway. The field measurement of mining roadway surrounding rock displacement in Zouzhuang coal mine working face 3204 verified the accuracy of theoretical analysis and numerical simulation.

Parameter Optimization and Numerical Analysis of the Special Soft Coal Seam Roadway with Large Inclination Dip

2012 ◽  
Vol 256-259 ◽  
pp. 1422-1428
Author(s):  
Tie Qi Zheng ◽  
Dong Ming Guo ◽  
Yu Fei Zhang ◽  
Jian Lv
Keyword(s):  
Numerical Analysis ◽  
Coal Seam ◽  
Large Scale ◽  
Program Verification ◽  
Simulation Analysis ◽  
Surrounding Rock ◽  
Soft Coal ◽  
Roadway Support ◽  
Fractured Coal ◽  
Soft Coal Seam

Mechanized mining of Longwall top coal caving mining method was used in 1201 work face of thick soft coal seam in Du Jiacun Mine. The face is back to the wind drift along the seam floor excavation, transport drift along the seam roof boring the two crossheading basic fullcoal roadway, due to the relatively soft coal body, joints fractured, coal strength is low, and the coal-rock inclination, roadway section, the weakness of the surrounding rock rock, resulting in the excavation and support difficulties. This chapter based on numerical computation FLAC3D large-scale numerical analysis software, on the inclination special soft coal seam using a different roadway, support method, numerical simulation analysis of the support parameters, the contrast in different roadway support system support parameters, the deformation of surrounding rock displacement, stress distribution, the distribution of plastic zone, the big dip is extremely soft for Du Village coal mine mining Gateway support programs, and through on-site ground pressure observation of program verification.

The Adaptation Analysis of the Fully Mechanized Coal Mining Face of Huopu Mine’s Third Soft Coal Seam

2014 ◽  
Vol 1049-1050 ◽  
pp. 335-338 ◽  
Author(s):  
Fa Quan Liu ◽  
Xue Wen Geng ◽  
Yong Che ◽  
Xiang Cui
Keyword(s):  
Coal Seam ◽  
Coal Mining ◽  
Geological Condition ◽  
Soft Coal ◽  
Working Face ◽  
Mining Face ◽  
Soft Coal Seam ◽  
Working Resistance

To get the maximum coal in front of the working face of the 17# coal seam, we installed a longer beam which is 1.2m in length in the leading end of the original working face supports ZF3000/17/28, and know that working face supports’ setting load and working resistance are lower .We changed the original supports with shield supports ZY3800/15/33 that are adaptable in the geological condition and got the favorable affection.

scholarly journals Permeability Enhancement Properties of High-Pressure Abrasive Water Jet Flushing and Its Application in a Soft Coal Seam

2021 ◽  
Vol 9 ◽  
Author(s):  
Xinzhe Zhang ◽  
Piotr Wiśniewski ◽  
Sławomir Dykas ◽  
Guojie Zhang
Keyword(s):  
High Pressure ◽  
Coal Seam ◽  
Water Jet ◽  
Gas Pressure ◽  
Theory And Practice ◽  
Abrasive Water Jet ◽  
Gas Drainage ◽  
Permeability Enhancement ◽  
Soft Coal ◽  
Soft Coal Seam

High-pressure abrasive water jet flushing (HPAWJF) is an effective method used to improve coal seam permeability. In this study, based on the theories of gas flow and coal deformation, a coupled gas-rock model is established to investigate realistic failure processes by introducing equations for the evolution of mesoscopic element damage along with coal mass deformation. Numerical simulation of the failure and pressure relief processes is carried out under different coal seam permeability and flushing length conditions. Distributions of the seepage and gas pressure fields of the realistic failure process are analyzed. The effects of flushing permeability enhancement in a soft coal seam on the gas drainage from boreholes are revealed by conducting a field experiment. Conclusions can be extracted that the gas pressure of the slotted soft coal seam is reduced and that the gas drainage volume is three times higher than that of a conventional borehole. Field tests demonstrate that the gas drainage effect of the soft coal seam is significantly improved and that tunneling speed is nearly doubled. The results obtained from this study can provide guidance to gas drainage in soft coal seams regarding the theory and practice application of the HPAWJF method.

scholarly journals Research on Control of Rib Spalling Disaster in the Three-Soft Coal Seam

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Feng Cui ◽  
Tinghui Zhang ◽  
Xiaoqiang Cheng
Keyword(s):  
Coal Seam ◽  
Field Experiments ◽  
Simulation Experiment ◽  
Current Status ◽  
Soft Coal ◽  
Grouting Pressure ◽  
Working Face ◽  
Coal Wall ◽  
Soft Coal Seam ◽  
Seam Mining

Rib spalling disaster at the coal mining faces severely restricted the safe and efficient output of coal resources. In order to solve this problem, based on the analysis of the current status of rib spalling in the three-soft coal seam 1508 Working Face of Heyang Coal Mine, a mechanical model of sliding-type rib spalling was established and the main influencing factors that affect rib spalling are given. The mechanism of grouting technology to prevent and control rib spalling has been theoretically analyzed. A similarity simulation experiment is used to analyze the change law of roof stress under the condition of three-soft coal seam mining. The optimal grouting pressure is determined by a numerical simulation experiment. And, silicate-modified polymer grouting reinforcement materials (SMPGMs) are used in field experiments. After twice grouting operations in the 1508 Working Face, the coal wall was changed from the original soft and extremely easy rib spalling to a straight coal wall and the amount of rib spalling has been reduced by 57.45% and 48.43, respectively. And, the mining height has increased by 0.16 m and 0.23 m, respectively. The experimental results show that the rib spalling disaster of the three-soft coal seam has been effectively controlled.

scholarly journals Application of Sampling Method Based on Negative Pressure Pneumatic Conveying in Soft Coal Seam

2016 ◽  
Vol 34 (3) ◽  
pp. 473-478
Author(s):  
Hongtu Zhang ◽  
Jianping Wei ◽  
Yungang Wang ◽  
Zhihui Wen ◽  
Banghua Yao
Keyword(s):  
Coal Seam ◽  
Negative Pressure ◽  
Sampling Method ◽  
Pneumatic Conveying ◽  
Soft Coal ◽  
Soft Coal Seam
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