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Han J.,LIAONING Technical University | Han J.,The State Key Laboratory of Coal Resources and Mine Safety | Han J.,KaiLuan Group Co. | Zhang H.W.,LIAONING Technical University | And 2 more authors.
Safety Science | Year: 2012

In order to obtain the characteristics of in situ stress field in outburst mining area, using the hollow inclusion (HI) technique to measure the in situ stress of coal and gas outburst mining area. The measurement sites located in northeast, middle and east of china, which include eight mining areas such as Fuxin, Pingdingshan, Hebi and Huainan. Base on the analysis of measurement data from outburst mining area, conclusions could be obtained as follow: (a) major principal stress and minor principal stress is horizontal stress and interim principal stress is vertical stress, and the type of outburst area's stress field is dynamic stress field; (b) the major principal stress and minor principal stress are higher than other regions and the tectonic stress is outstanding; and (c) the ratio of major principal and vertical stress is decrease with the increase of depth and the type of stress field is likely transfer dynamic to static. Thus, in situ stress plays a key role during the occurring and development of coal and gas outburst, which is an important reason of severe outburst in China. © 2011. Source

Yao B.,Henan Polytechnic University | Du F.,Henan Polytechnic University | Du F.,The State Key Laboratory of Coal Resources and Mine Safety | Li E.,Henan Polytechnic University | Wang X.,Henan Polytechnic University
Electronic Journal of Geotechnical Engineering | Year: 2014

In order to study the water inrush mechanics of Karst collapse columns, based on the seepage theory of pores media and elastic plastic mechanical theory, a mechanical model of Karst collapse column water inrush under the effect of surrounding stress, gravity and water pressure was obtained, and we deduced the critical water pressure for rock failure by using D-P criterion, then we made the equations into the COMSOL Multiphysics, obtaining the failure zone in collapse column under different water pressure as well as the failure evolution rule as seepage from bottom to the top, and tested the correctness of the theory and numerical simulation. The research results indicate that: (1) there is a critical water pressure for collapse column which is determined by both the mechanical property and stress state; (2) water inrush of collapse columns will not happen quickly after they were exposed, while the failure zone evolved from bottom to the top caused by seepage as the time and finally resulted in water inrush; (3) the larger the water pressure is, the easier water inrush of collapse column will be. © 2014, EJGE. Source

Yuan H.-P.,Hefei University of Technology | Yuan H.-P.,The State Key Laboratory of Coal Resources and Mine Safety | Han Z.-Y.,Hefei University of Technology | Lin H.,The State Key Laboratory of Coal Resources and Mine Safety | And 3 more authors.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2014

In view of the rebound phenomenon in numerical simulation calculation of rock & soil excavation, based on the M-C elastic-plastic constitutive model, the rebound effect is studied during the excavation process of a foundation pit. The mechanical mechanism and the sensitivity of the mechanical parameters for the rebound effect in rock mass constitutive model are analyzed. Besides, the solution to the rebound in numerical simulation of excavation is explored. The research results show that the effect of parameters in the M-C constitutive model on the rebound is as follows: (1) The impact of geotechnical gravity density on rebound of general rock mass excavation is relatively sensitive, and the effect on the bottom is far more significant than that on the surface. (2) The effect of Poisson's ratio on rebound displacement of excavating rock & soil is also obvious. (3) When the ratio of reduction is small, the sensitivity of elastic modulus and cohesive force is prominent. The effect on the bottom and the surface is significant on the whole. (4) However, the internal friction angle of rock and soil basically has no effect on the bound deformation. This study may provide reference for the design of excavation of foundation pits and rebound prediction. Source

Yang W.,The State Key Laboratory of Coal Resources and Mine Safety | Yang W.,China University of Mining and Technology | Lin B.-Q.,The State Key Laboratory of Coal Resources and Mine Safety | Lin B.-Q.,China University of Mining and Technology | And 8 more authors.
Dongbei Daxue Xuebao/Journal of Northeastern University | Year: 2011

The mining activity can cause the stress redistribution, and thus generate stress relief and concentration areas, which will greatly affect the gas flow and its control methods. In this paper, the stress distribution and evolution was studied based on numerical simulation. It is indicated that the stress in the O-shaped ring is much lower near the coal seam, and as far away, the stress gradually increases while the O-shaped ring shrinks increasingly. When the coal face was 96 m wide, the mining activity will result in stress relief in the range of 40 m above and 20 m below the coal seam. Therefore, the rock mass was classified into four kinds according to the stress states which were re-compacted, stress relief, stress concentration and original stress zones from inside to outside, respectively. The four zones described the stress distribution and provided a theory basis for gas control. Source

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