scholarly journals Multiparameter Monitoring and Prevention of Fault-Slip Rock Burst

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Shan-chao Hu ◽  
Yun-liang Tan ◽  
Jian-guo Ning ◽  
Wei-Yao Guo ◽  
Xue-sheng Liu
Keyword(s):  
Rock Burst ◽  
Early Warning ◽  
Large Diameter ◽  
Early Warning Systems ◽  
Fault Slip ◽  
Pressure Relief ◽  
Stick Slip ◽  
Research Results ◽  
Rock Bursts ◽  
Induced Stress

Fault-slip rock burst is one type of the tectonic rock burst during mining. A detailed understanding of the precursory information of fault-slip rock burst and implementation of monitoring and early warning systems, as well as pressure relief measures, are essential to safety production in deep mines. This paper first establishes a mechanical model of stick-slip instability in fault-slip rock bursts and then reveals the failure characteristics of the instability. Then, change rule of mining-induced stress and microseismic signals before the occurrence of fault-slip rock burst are proposed, and multiparameter integrated early warning methods including mining-induced stress and energy are established. Finally, pressure relief methods targeting large-diameter boreholes and coal seam infusion are presented in accordance with the occurrence mechanism of fault-slip rock burst. The research results have been successfully applied in working faces 2310 of the Suncun Coal Mine, and the safety of the mine has been enhanced. These research results improve the theory of fault-slip rock burst mechanisms and provide the basis for prediction and forecasting, as well as pressure relief, of fault-slip rock bursts.

scholarly journals Mechanism and Control of Roadway Floor Rock Burst Induced by High Horizontal Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Dongming Guo ◽  
Xinchao Kang ◽  
Zhiying Lu ◽  
Qiyu Chen
Keyword(s):  
Rock Burst ◽  
Prevention And Control ◽  
Large Diameter ◽  
Horizontal Stress ◽  
Steel Tube ◽  
Pressure Relief ◽  
Floor Rock ◽  
Concrete Filled Steel Tube ◽  
Rock Burst Risk ◽  
And Control

According to the characteristics of rock burst of high horizontal stress roadway floor, the rock burst mechanism of roadway floor was studied with the background of south track roadway Xing’an mine. Based on the deflection theory and energy principle of the slab, the mechanical model of the floor of the roadway under high horizontal stress was established, the stress and energy criteria of rock burst occurred in the floor of the roadway were deduced, the prevention and control measures of the floor pressure relief with large diameter borehole and concrete-filled steel tube pile support were put forward, and the key parameters were determined. By establishing a numerical model, the evolution law of plastic zone, horizontal stress, and elastic strain energy density of roadway floor with or without support is contrastively analyzed. The results show that the effective means to prevent and control the floor rock burst is to cut off the stress transfer path by weakening the hard floor to reduce floor energy accumulation so as to reduce the floor rock burst risk. Based on the above research, field tests were carried out, and the microseismic monitoring results showed that the floor pressure relief of large diameter boreholes and concrete-filled steel tube pile support effectively relieved the floor rock burst and guaranteed the safety and efficiency of roadway excavation. This technology can provide a reference for the prevention and control of floor rock burst of similar roadways.

scholarly journals Study on Rock Burst Early Warning in the Working Face of Deep Coal Mines Based on the Law of Gas Emission

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Qinghua Zhang ◽  
Shudong He
Keyword(s):  
Rock Burst ◽  
Early Warning ◽  
Critical Value ◽  
Gas Emission ◽  
Distribution Law ◽  
Deep Mine ◽  
Gas Concentration ◽  
Research Results ◽  
Working Face ◽  
The Law

This study is aimed at predicting rock burst disasters in high gas mines. First, the distribution law and correlation of gas and stress in the F15-17-11111 working face of Pingdingshan No. 13 Mine were analyzed based on the coupling relationship between gas emission and stress in the working face. Next, the relationship between gas emission and stress distribution was revealed, and an early warning method of rock burst in the deep mine working face based on the law of gas emission was proposed and applied to the F15-17-11111 working face. Finally, the critical value of the gas concentration indicator for rock burst early warning in the F15-17-11111 working face was determined as 0.05%. The following research results were obtained. The gas emission and the mining stress in the F15-17-11111 working face are negatively correlated. Mechanically, their correlation satisfies the typical coupling. Besides, the critical value of the gas concentration indicator determined by the proposed early warning method boasts high accuracy in predicting rock burst disasters. It can be used as an early warning method for underground rock burst disasters to promote the safety of working face mining. The research results provide reference and guidance for the monitoring and early warning of rock burst disasters in deep high gas mines.

scholarly journals Analysis on Rock Burst Risks and Prevention of a 54 m-Wide Coal Pillar for Roadway Protection in a Fully Mechanized Top-Coal Caving Face

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Zhihua Li ◽  
Ke Yang ◽  
Jianshuai Ji ◽  
Biao Jiao ◽  
Xiaobing Tian
Keyword(s):  
Coal Seam ◽  
Rock Burst ◽  
Influencing Factors ◽  
Abutment Pressure ◽  
Large Diameter ◽  
Coal Pillar ◽  
Distribution Characteristics ◽  
Pressure Relief ◽  
Working Face ◽  
Coal Pillars

A case study based on the 401103 fully mechanized caving face in the Hujiahe Coal Mine was carried out in this research to analyze the rock burst risks in a 54 m-wide coal pillar for roadway protection. Influencing factors of rock burst risks on the working face were analyzed. Stress distribution characteristics on the working face of the wide coal pillar for roadway protection were discussed using FLAC3D numerical simulation software. Spatial distribution characteristics of historical impact events on the working face were also investigated using the microseismic monitoring method. Results show that mining depth, geological structure, outburst proneness of coal strata, roof strata structure, adjacent mining area, and mining influence of the current working face are the main influencing factors of rock burst on the working face. Owing to the collaborative effects of front abutment pressure of the working face and lateral abutment pressure in the goaf, the coal pillar is in the ultimate equilibrium state and microseismic events mainly concentrate in places surrounding the coal pillars. Hence, wide coal pillars become the regions with rock burst risks on the working face. The working face adopts some local prevention technologies, such as pressure relief through presplitting blasting in roof, pressure relief through large-diameter pores in coal seam, coal seam water injection, pressure relief through large-diameter pores at bottom corners, and pressure relief through blasting at bottom corners. Moreover, some regional prevention technologies were proposed for narrow coal pillar for roadway protection, including gob-side entry, layer mining, and fully mechanized top-coal caving face with premining top layer.

scholarly journals Study on Pressure Relief Effect of Rock Mass with Different Borehole Parameters

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Chao Peng ◽  
Wanrong Liu
Keyword(s):  
Acoustic Emission ◽  
Rock Mass ◽  
Rock Burst ◽  
Strength Reduction ◽  
Surrounding Rock ◽  
Reduction Degree ◽  
Occurrence Time ◽  
Pressure Relief ◽  
Research Results ◽  
Relief Effect

Rock burst is one of the disaster accidents that can easily happen in rock cavern engineering. At present, one of the most commonly used methods to control rock burst is borehole pressure relief technology. In this paper, the influence of drilling layout schemes on the pressure relief effect of surrounding rock mass is systematically studied. The research results show that the strength reduction degree, AE evolution characteristics, failure modes of rock samples with different borehole positions, boreholes spacing, boreholes dip angles, and boreholes layout forms are different. The strength reduction degree of rock sample with an inclined arrangement form is the largest, followed by the arrangement form being up three-flower layout or down three-flower layout. Using the inclined layout and three-flower layout can achieve better pressure relief effect of the surrounding rock mass. The research results are beneficial to the rock burst of surrounding rock of the cavern. The acoustic emission can effectively monitor the stability of the surrounding rock of the cavern. However, the threshold value and the occurrence time of the acoustic emission of the cavern instability changed after the cavern surrounding rock is drilled holes. If the borehole is arranged at the surrounding rock mass, the occurrence time of the cavern instability may be advanced.

scholarly journals Stress Relief and Support for Stability of Deep Mining Roadway with Thick Top Coal in Hujiahe Coal Mine with the Risk of Rock Burst

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Wenjing Liu ◽  
Deyu Qian ◽  
Xingguo Yang ◽  
Sujian Wang ◽  
Jinping Deng ◽  
...  
Keyword(s):  
Rock Burst ◽  
Coal Mine ◽  
Large Diameter ◽  
Stability Control ◽  
Surrounding Rock ◽  
Shaanxi Province ◽  
Pressure Relief ◽  
Working Face ◽  
Deformation Speed ◽  
Plastic Transformation

Rock burst is a typical dynamic disaster in deep underground coal mining. Based on the support problems of the deep roadways in fully mechanized caving face 401111 of Hujiahe Coal Mine suffering from rock burst in Shaanxi Province of China, the failure law and influencing factors of the surrounding rock of the roadway are analyzed. The results show that the deformation of surrounding rock in the roadway shows the characteristics of elastic, plastic transformation, rheology, and expansion. At the same time, it has the typical characteristics of deep roadway, such as the fast deformation speed, long duration, asymmetric deformation, and large loose broken area of surrounding rock. Based on the principle of “strengthening support in shallow zones” and “deep pressure relief in deep zones” in the surrounding rock, the control scheme of surrounding rock in the return roadway of fully mechanized caving working face 401111 is proposed by taking the large diameter pressure relief and deep hole blasting as the main means of pressure relief. The practice shows that the surrounding rock of the return roadway is relatively stable after the implementation of the new scheme, which shows that the design of the new support scheme is reasonable and reliable. It is of great significance for the stability control of surrounding rock of the mining roadway suffering from rock burst.

scholarly journals Application of Data Mining in an Intelligent Early Warning System for Rock Bursts

Processes ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 55 ◽  
Author(s):  
Xuejun Zhu ◽  
Xiaona Jin ◽  
Dongdong Jia ◽  
Naiwei Sun ◽  
Pu Wang
Keyword(s):  
Data Mining ◽  
Data Warehouse ◽  
Rock Burst ◽  
Early Warning ◽  
Early Warning System ◽  
Warning System ◽  
Monitoring Data ◽  
Efficient Production ◽  
Mining Technology ◽  
Rock Bursts

In view of rock burst accidents frequently occurring, a basic framework for an intelligent early warning system for rock bursts (IEWSRB) is constructed based on several big data technologies in the computer industry, including data mining, databases and data warehouses. Then, a data warehouse is modeled with regard to monitoring the data of rock bursts, and the effective application of data mining technology in this system is discussed in detail. Furthermore, we focus on the K-means clustering algorithm, and a data visualization interface based on the Browser/Server (B/S) mode is developed, which is mainly based on the Java language, supplemented by Cascading Style Sheets (CSS), JavaScript and HyperText Markup Language (HTML), with Tomcat, as the server and Mysql as the JavaWeb project of the rock burst monitoring data warehouse. The application of data mining technology in IEWSRB can improve the existing rock burst monitoring system and enhance the prediction. It can also realize real-time queries and the analysis of monitoring data through browsers, which is very convenient. Hence, it can make important contributions to the safe and efficient production of coal mines and the sustainable development of the coal economy.

scholarly journals Pattern Recognition of Signals for the Fault-Slip Type of Rock Burst in Coal Mines

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
X. S. Liu ◽  
J. Tan ◽  
Y. L. Tan ◽  
S. C. Hu
Keyword(s):  
Pattern Recognition ◽  
Electromagnetic Radiation ◽  
Rock Burst ◽  
Early Warning ◽  
Mechanical Model ◽  
Fault Slip ◽  
Coal Face ◽  
Major Threat ◽  
Good Agreement

The fault-slip type of rock burst is a major threat to the safety of coal mining, and effectively recognizing its signals patterns is the foundation for the early warning and prevention. At first, a mechanical model of the fault-slip was established and the mechanism of the rock burst induced by the fault-slip was revealed. Then, the patterns of the electromagnetic radiation, acoustic emission (AE), and microseismic signals in the fault-slip type of rock burst were proposed, in that before the rock burst occurs, the electromagnetic radiation intensity near the sliding surface increases rapidly, the AE energy rises exponentially, and the energy released by microseismic events experiences at least one peak and is close to the next peak. At last, in situ investigations were performed at number 1412 coal face in the Huafeng Mine, China. Results showed that the signals patterns proposed are in good agreement with the process of the fault-slip type of rock burst. The pattern recognition can provide a basis for the early warning and the implementation of relief measures of the fault-slip type of rock burst.

scholarly journals Study on Microseismic Monitoring, Early Warning, and Comprehensive Prevention of a Rock Burst under Complex Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Ke Ding ◽  
Lianguo Wang ◽  
Mei Yu ◽  
Wenmiao Wang ◽  
Bo Ren
Keyword(s):  
Coal Seam ◽  
Rock Burst ◽  
Large Diameter ◽  
Elastic Strain Energy ◽  
Surrounding Rock ◽  
Control Effect ◽  
Pressure Relief ◽  
Working Face ◽  
Geological Conditions ◽  
Microseismic Events

Rock bursts in coal mines are usually unpredictable. In view of this problem, the energy–frequency relationship and spatial distribution characteristics of microseismic events during the mining of 5305 working face in Xinhe Coal Mine under complex geological conditions were analyzed in this study. Besides, the law and precursors of rock burst occurrence in this working face were discussed. The following research results were obtained. Before the rock burst occurred in 5305 working face, the energy and frequency of microseismic events vary in the following order: “peak-drop-rise-rock burst.” The analysis on spatial characteristics of microseismic events suggests that microseismic events were mainly concentrated at the boundary between the roof and the coal seam or at the hard roof near the coal seam within 0–160 m in front of the working face, and most of the events lay on the goaf side. Moreover, the energy and frequency of microseismic events both decrease in the above region before the rock burst occurred. This “microseismic event absence” phenomenon can be regarded as one of the precursors of rock burst occurrence. In addition, a multilevel antiburst scheme was proposed for the complex conditions: (1) to adopt large-diameter boreholes pressure relief technology and key layer high-level pressure relief technology for adjusting the stress distribution in the surrounding rock of crossheading in front of the working face and dissipating elastic strain energy; (2) to determine the advance speed to be 1.5 m/d for reducing the mining disturbance; (3) to adopt full-section reinforced support of the roadway for enhancing the antiburst capacity of surrounding rock. After the implementation of this scheme, the energy and frequency of microseismic events monitored on-site changed gently, and 5305 working face was safely recovered to the stop line position. The scheme boasts a remarkable rock burst prevention and control effect.

The CARE Telematics Network for the Surveillance of Influenza in Europe

1995 ◽  
Vol 34 (05) ◽  
pp. 518-522 ◽  
Author(s):  
M. Bensadon ◽  
A. Strauss ◽  
R. Snacken
Keyword(s):  
Public Health ◽  
Early Warning ◽  
Early Warning Systems ◽  
Warning Systems ◽  
Surveillance Networks ◽  
Spanish Flu ◽  
The 1950S ◽  
National Networks ◽  
First Time

Abstract:Since the 1950s, national networks for the surveillance of influenza have been progressively implemented in several countries. New epidemiological arguments have triggered changes in order to increase the sensitivity of existent early warning systems and to strengthen the communications between European networks. The WHO project CARE Telematics, which collects clinical and virological data of nine national networks and sends useful information to public health administrations, is presented. From the results of the 1993-94 season, the benefits of the system are discussed. Though other telematics networks in this field already exist, it is the first time that virological data, absolutely essential for characterizing the type of an outbreak, are timely available by other countries. This argument will be decisive in case of occurrence of a new strain of virus (shift), such as the Spanish flu in 1918. Priorities are now to include other existing European surveillance networks.

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