Key Laboratory of Western Mines and Hazard Prevention

Fengcheng, China

Key Laboratory of Western Mines and Hazard Prevention

Fengcheng, China

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Cui F.,Xi'an University of Science and Technology | Cui F.,Key Laboratory of Western Mines and Hazard Prevention | Lai X.P.,Xi'an University of Science and Technology | Lai X.P.,Key Laboratory of Western Mines and Hazard Prevention | And 2 more authors.
Rock Mechanics: Achievements and Ambitions - Proceedings of the 2nd ISRM International Young Scholars' Symposium on Rock Mechanics | Year: 2012

Low recovery is a problem existing in top coal caving mining of steep and thick coal seams. Pre-blasting in top-coal for weakening the coal seam is proposed to solve this prblem. Based on the background of pre-blasting working face in Jiangou coal mine, the numerical analysis model of long holes pre-blasting was established. By numerical analysis with nonlinear program LS-DYNA, the parameters of blasting for presplit coal, stress-strain state in the pre-blasting influenced zone were studied. The purpose of the study was for keeping stability of the surrounding roadways while effective weakening in the top coal. The results showed that thickness of the retaining top coal above the support frane was 3.0 to 4.0 meters, the horizontal distance between final position for pre-explosion hole and roadway was not less than 4 meters, the vertical distance between explosive bottom for pre-explosion hole and the top of roadway was not less than 4 meters, the row spacing for pre-explosion hole was 4.0 meters. Pre-blasting with these parameters got effective weakening results with the roadways in stable conditions. © 2012 Taylor & Francis Group.


Tian S.C.,Xi'an University of Science and Technology | Tian S.C.,Key Laboratory of Western Mines and Hazard Prevention | Yang X.J.,Xi'an University of Science and Technology | Yang X.J.,Key Laboratory of Western Mines and Hazard Prevention
Conference Proceedings of the 4th International Symposium on Project Management, ISPM 2016 | Year: 2016

As the importance of the effect of judging the miners' unsafe behavior factors, as much as possible to prevent unsafe behavior, we use the related principle of AHP, the establishment of composed of four first-order factors and 16 second level factors of unsafe behavior influencing factors set, hierarchical structure model is constructed, through expert scoring, these factors were compared. Using MATLAB software to calculate the weight of primary factors and secondary factors, and weight of the total order and consistency test, to analyze the importance for influencing factors. The most important is environmental factors in importance ranking. It will be as the miners' unsafe behavior pre control basis, provides certain reference value to the prevention and control of coal mine accidents.


Lai X.-P.,Xi'an University of Science and Technology | Lai X.-P.,Key Laboratory of Western Mines and Hazard Prevention | Yang Y.-R.,Xi'an University of Science and Technology | Yang Y.-R.,Key Laboratory of Western Mines and Hazard Prevention | And 7 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2016

Dynamic hazards being induced by mining stress always threaten safe mining in extremely steep and thick coal seams. Aimed at prevention and control of dynamic hazards in Wudong Coal Mine, Urumchi mine area, we applied a comprehensive methodology including in-situ investigation, theoretical analysis, numerical calculation and field monitoring to reveal mechanism of dynamic hazards being induced by distorted mining stress. The relevant results indicate that mining stress transfer from top of the No. 43 coal seam to sandwiched coal-rock pillar in seams (SCPS), and SCPS deformed largely towards mine-out-area due to self-gravity, which causes tensile stress in its upper position and compressive stress in the bottom. Furthermore, high stress concentration is formed in the roof of the +575 level of No. 45 coal seam, leading to substantial dynamic hazards. With fully considering existing mining scheme, coupled fracturing that we injected water firstly and then blasted rock masses have been put forward and applied as hazard-relieving measures. By means of micro-seismic monitoring and electromagnetic radiation intensity, the frequency of micro-seismic big events decrease to one time per minute from four time per time, and the peak intensity of electromagnetic radiation reduces to about 42.8 mV below the precautious line. Dynamic hazards relief obviously. © 2016, Editorial Office of Journal of China Coal Society. All right reserved.


Lai X.-P.,Xi'an University of Science and Technology | Lai X.-P.,Key Laboratory of Western Mines and Hazard Prevention | Wu Y.-P.,Xi'an University of Science and Technology | Wu Y.-P.,Key Laboratory of Western Mines and Hazard Prevention | And 8 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2010

Aimed at quantitatively prediction the process of rock-mass localized deformation regularity and their relating indicators of Nindong coal region in broken rock-mass induced historical seismicity and rich water environment, and comprehensive analyzed geophysical characteristics, loading framework and its mechanical performance, invalid indicators of rock-mass deformation and their quantitative discrimination methods, structure and flaw and characterization of simulative material, etc., the largest scale 3D physical simulative assembly was constructed with integrated real-time monitoring system of multi-acoustics-optics-electricity-indicators, and experiment was undertaken with the constant and variable static-dynamical loading model. The acoustic emission(AE) characteristics and their regularity relating to rock-mass localized fracture were acquired, and distributing characteristics of radial and tangential stress in excavation disturbance were statistically and comparatively discriminated. The results obviously indicate that the durable damage and deformation may bring potentially after the crack and deformation of complex rockmass undergo oscillatory and quietness. Even, the characteristics will be found upon localized destabilization of composite coal and rockmass.


Lai X.-P.,Xi'an University of Science and Technology | Lai X.-P.,Key Laboratory of Western Mines and Hazard Prevention | Qi T.,Shenhua Xinjiang Energy Co. | Jiang D.-H.,Shenhua Xinjiang Energy Co. | And 6 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2011

Initially, according to theoretical analysis, investigations of geological environment and mining conditions, the methodology was proposed to monitor multiple indicating upon coal/rock fracture and destabilization. Afterwards, the borehole stress apparatus indicating vertical stress, optical borehole peeper and broken range of top coal instrument, etc. were performed in mining field, the regularity of stress and deformation of top coal were analyzed comprehensively in the process of the segment pre-blasting. Ultimately, the dimension of segment pre-blasting and supporting were confirmed, respectively, to be of 10.0~35.0 m and 0~45.0 m.


Lai X.-P.,Xi'an University of Science and Technology | Lai X.-P.,Key Laboratory of Western Mines and Hazard Prevention | Zheng J.-W.,Xi'an University of Science and Technology | Zheng J.-W.,Key Laboratory of Western Mines and Hazard Prevention | And 5 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2015

With coal excavation, the surrounding rock of roadway in a fault broken zone might induce a dynamic hazard in a coal mine. The determination of internal critical destabilization range plays an important part in supporting parameter optimization and safe excavation. Disturbed zone of roadway at 1193 working face in Tunbao coal district was investigated in this study. In order to control the stability of rock-mass in fault broken zone, engineering geology investigation, theoretical analysis and site monitoring were used to study the range of internal critical destabilization in fault influenced broken zone. It shows that the range could be 2.30 m combined with hybrid consideration including statistical analysis of cracks and internal cracks propagation of surrounding rock with various depths. Different support loadings were given based on different destabilization ranges between roof side and coal seam side. The optimized design of roadway achieved good results in safety and efficient mining. ©, 2015, China Coal Society. All right reserved.


Cui F.,Xi'an University of Science and Technology | Cui F.,Key Laboratory of Western Mines and hazard Prevention | Lai X.P.,Xi'an University of Science and Technology | Lai X.P.,Key Laboratory of Western Mines and hazard Prevention | And 2 more authors.
47th US Rock Mechanics / Geomechanics Symposium 2013 | Year: 2013

Majority of the coal seams in Urumqi coal field, located in Xinjiang Province, China, are dipping about or above 45 degrees, called steeply dipping coal seams. The maximum width of the coal seams group is about 50m, and the minimum width is only 20m. and the vertical height is more than 400m. At present, the mining method used for these seams is the horizontal section top-coal caving mining. In this paper, the caving effect of steeply dipping and thick coal seams after weakening are studied with numerical simulation. The migration path and the falling quantity of discrete coal particles are analyzed and the distribution characteristics of hinged force between flowing blocks are intuitively presented. The load change of supports in the process of top-coal caving is monitored in real time, and the expression equation for caving space in flow model is established. The mining practice shows that the coal mass can be separated by using the advance pre-blasting method, which improves the top-coal recovery rate and reduces the loss of resource. Copyright 2013 ARMA, American Rock Mechanics Association.


Zhao J.-H.,Xi'an University of Science and Technology | Lai X.-P.,Xi'an University of Science and Technology | Lai X.-P.,Key Laboratory of Western Mines and Hazard Prevention
Journal of Coal Science and Engineering | Year: 2011

For mining extra-steep-thick coal seam, the sublevel top coal caving is a high efficient method in practical engineering. However, major challenges associated with mining high-section top-coal-caving (HSTCC) are related to the resulting high ground stresses. Inevitability, using the high-section sublevel top coal caving for extra-steep-thick coal seam, the large scale of mined-out area appears. If the prefracture blasting and hydraulic fracture techniques are utilized, the top coal damage and cracks will develop, and the mining complexity will increase, such as seam inclination, continuity, mechanical characteristics of roof and susceptibility of top coal, etc. First, the field conditions of B 1+2 seam were investigated at the +588 level of the Weihuliang Underground Mine of China. Subsequently, according to caving mechanism of strata response obtained from several special models including physical simulation tests and numerical simulation models, the prefracture process including blasting and injecting water were analyzed. Then, the prefracture blasting technique was successfully applied to the caving of 52 m-sublevel seam. Finally, the effects were verified by advanced detecting instruments, and the results show these methods and measurements are feasible and valid. © The Editorial Office of Journal of Coal Science and Engineering (China) and Springer-Verlag Berlin Heidelberg 2011.


Qiu H.F.,Shaanxi University of Science and Technology | Qiu H.F.,Key Laboratory of Western Mines and Hazard Prevention | Lai X.P.,Shaanxi University of Science and Technology | Lai X.P.,Key Laboratory of Western Mines and Hazard Prevention | And 2 more authors.
Transit Development in Rock Mechanics-Recognition, Thinking and Innovation - Proceedings of the 3rd ISRM Young Scholars Symposium on Rock Mechanics, 2014 | Year: 2015

Taking the project in China as background, established a physical model experimental platform to simulate the cavity construction using the similar theory. The influence of interlayer to the cavity construction was studied. It was found: when the interlayer exists, the flow field becomes more complex; and the brine distribution besides the interlayer will be changed. Thus the dissolution of salt rock besides the interlayer was affected which results the triangle insoluble inclination appearing on the top of the interlayer, making the cave building inefficient and being not conducive to the cave shape control. It is the key to make the interlayer reasonable collapse in cavity construction. © 2015 Taylor & Francis Group, London.


Lai X.P.,University of Science and Technology of China | Lai X.P.,Key Laboratory of Western Mines and Hazard Prevention | Shan P.F.,University of Science and Technology of China | Shan P.F.,Key Laboratory of Western Mines and Hazard Prevention | And 6 more authors.
Rock Mechanics and Rock Engineering | Year: 2015

When mechanized sub-horizontal section top coal caving (SSTCC) is used as an underground mining method for exploiting extremely steep and thick coal seams (ESTCS), a large-scale surrounding rock caving may be violently created and have the potential to induce asymmetric destabilization from mine voids. In this study, a methodology for assessing the destabilization was developed to simulate the Weihuliang coal mine in the Urumchi coal field, China. Coal-rock mass and geological structure characterization were integrated with rock mechanics testing for assessment of the methodology and factors influencing asymmetric destabilization. The porous rock-like composite material ensured accuracy for building a 3D geological physical model of mechanized SSTCC by combining multi-mean timely track monitoring including acoustic emission, crack optical acquirement, roof separation observation, and close-field photogrammetry. An asymmetric 3D modeling analysis for destabilization characteristics was completed. Data from the simulated hydraulic support and buried pressure sensor provided effective information that was linked with stress–strain relationship of the working face in ESTCS. The results of the 3D physical model experiments combined with hybrid statistical methods were effective for predicting dynamic hazards in ESTCS. © 2015 The Author(s)

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