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Jiang F.-X.,University of Science and Technology Beijing | Wang J.-C.,University of Science and Technology Beijing | Sun G.-J.,Shandong Xinjulong Energy Ltd Company | Zhu S.-T.,University of Science and Technology Beijing
Meitan Xuebao/Journal of the China Coal Society | Year: 2015

In order to study the occurrence conditions of rock burst in gob-side entry in deep mining, the stress field distribution of gob-side entry was taken as entry point, and the corresponding engineering mechanical models were established. After analysis, the high stress difference region near the high stress region in the surrounding rock of gob-side entry is the main region of rock burst. Taking the coal of the high stress difference region as study object, the stress condition, stress gradient condition and bursting liability condition of rock burst occurrence in gob-side entry were gained by mechanical analysis, and the engineering criterion of rock burst hazard was deduced. The results show that the key factors of rock burst hazard are the stress maximum, the stress difference, the stress gradient, the strength and bursting liability of coal in the high stress difference region. And rock burst disaster of gob-side entry can be controlled effectively by determining the reasonable position of gob-side entry to adjust the spacing between substance coal roadway side of gob-side entry and stress peak of the high stress region. ©, 2015, Meitan Xuebao/Journal of the China Coal Society. All right reserved. Source


Ji D.,University of Science and Technology Beijing | Guo Q.,University of Science and Technology Beijing | Jia H.,Shandong Xinjulong Energy Ltd Company
International Journal of Digital Content Technology and its Applications | Year: 2012

The hollow inclusion cells with high accuracy and strong adaptability have been widely used for insitu stress measurement both in China and abroad. Confining pressure test, as an important means to acquire rock elastic parameters in data processing, has direct influence in the precision of calculation results. Nonetheless, the test conditions and rock nonlinear play an important role in the elastic parameters calculated by stress and strain under highest pressure, which could lead to major error. A multitude of experiment data obtained by the calibration test is implemented by different lithology of specimens with the help of confining pressure instrument; Based on the analysis of multiple error factors, the results were reasonable modified. Considering the effect of rock nonlinear, a calculation method in which elastic parameters are divided by different stress interval is proposed with the study of rock strain curve law, and the elastic constants of rock are various under different conditions of stress level. The method is applied to calculate geo-stresses of No.10 Mine of Pingdingshan Coal Mine Group, at 11 points distributed in 6 levels. The achieved results reveal this method is engineering practicable and offers a reference to the improvement of the accuracy in in-situ stress calculation. Source


Liu J.,University of Science and Technology Beijing | Jiang F.,University of Science and Technology Beijing | Wang N.,Shandong Xinjulong Energy Ltd Company | Li Z.,Shandong Xinjulong Energy Ltd Company | Zhang Z.,Shandong Xinjulong Energy Ltd Company
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2012

Setting reasonable segment pillar is key for ensuring successful replacement and safety production of fully mechanized caving face in extra-thick coal seam of deep shaft. Taking the determination of segment pillar width in the first mining area of Xinjulong mine as the engineering background, firstly, the side abutment pressure distribution of fully mechanized caving face in extra-thick coal seam of deep shaft was studied by using microseismic monitoring, stress monitoring and theoretical calculation, and 20 m in width of low stress zone was realized. Secondly, the width of fractured zone in side coal mass of fully mechanized caving face in extra-thick coal seam of deep shaft was determined by using engineering analogy and numerical modelling, and about 3m in width of fractured zone was found. Finally, various elements such as resources recovery, rockburst prevention and control, secondary disaster control and roadway support were considered comprehensively, and the reasonable width of segment pillar of fully mechanized caving face in extra-thick coal seam of deep shaft was determined as 5.0-7.2 m. Furthermore, the reasonableness of the segment pillar width was verified by using observation results of surface displacement of the gob-side entry. The results can provide a reference for segment pillar setting in other mines having similar mining conditions. Source


Ma L.-Q.,China University of Mining and Technology | Zhang D.-S.,China University of Mining and Technology | Sun G.-J.,Shandong Xinjulong Energy Ltd Company | Cui T.-H.,China University of Mining and Technology | Zhou T.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2013

The average thickness of the overlying bedrock of Longgu primary mine able coal seam is less than 200 m, but there is a thick alluvium averaging above 700 m above the bedrock. The bearing characteristic of fully mechanized long wall caving face with large mining height on the condition of unloading, the possibility of step sinking and its critical thickness are analyzed in order to solve the problems of the mine pressure at mining face and strata control under thick alluvium condition. The results show that, while its bearing capacity is not strong after large excavation under the bottom of deep alluvium and its weight is loaded on the underlying bedrock, the fracture zone can form a stable mechanical bearing structure when the thickness of the bedrock is more than 120 m, so the coalface roof can be controlled. On this basis, ZF15000/23/43 hydraulic support has been developed, with the largest working resistance in China. With this hydraulic support, the surrounding rock in fully mechanized caving coalface with large mining height under thick alluvium can be controlled. Source

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