Time filter

Source Type

Zheng X.,Key Laboratory of Deep Coal Resource Mining | Feng X.,Key Laboratory of Deep Coal Resource Mining | Zhang N.,Key Laboratory of Deep Coal Resource Mining | Zhang N.,Hunan University of Science and Technology | And 2 more authors.
Arabian Journal of Geosciences | Year: 2015

Bolt supports within stratified strata in coal mines contribute to the unique characteristics of low-buried engineering structures such as tunnels or subways. Failure at the bolt interface is the main trigger of support failure in such settings. This paper comprehensively investigates the serial decoupling mechanism at a resin–rock interface, which is a process that occurs frequently in stratified strata. There are, however, different evolutionary processes that exist at the interface, from a total bonding stage to a plastic bonding stage, a slippage plastic bonding stage, a slippage plastic stage and a total slippage stage, sequentially. These processes accelerate the shortening speed of anchor life, whereupon axial force will fluctuate at each stage and corresponding equations can be derived successfully. Finally, a long-term field monitoring test which verifies the theoretical results and effective measures, such as pregrouting, can be used to prevent serial decoupling. The service life of the bolt system also can be prolonged. © 2014, Saudi Society for Geosciences.


Wang X.-F.,China University of Mining and Technology | Wang X.-F.,State Key Laboratory of Coal Resources and Safe Mining | Wang X.-F.,Key Laboratory of Deep Coal Resource Mining | Zhang D.-S.,China University of Mining and Technology | And 4 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2013

Based on the main roof bearing asymmetrical loads when longwall mining under a sand-soil gully slope in shallow coal seam, theory analysis and field observation methods were used, the gully slope and its shape were considered, a roof structure mechanical model was established when the longwall working face backward-gully mining in first and periodic weighting, and a "support and surrounding rock" relation model was analyzed under given instability loads. Furthermore, the support resistance which could control the roof structure sliding instability was obtained. The support resistance changing features were analyzed along the working face advancement combined with practical geological conditions, and the rational support resistance calculation example was provided. The field observation result demonstrated the reliability of the method.


Chang Q.,China University of Mining and Technology | Chang Q.,Key Laboratory of Deep Coal Resource Mining | Zhou H.,China University of Mining and Technology | Zhou H.,Key Laboratory of Deep Coal Resource Mining | And 2 more authors.
International Journal of Mining Science and Technology | Year: 2013

Comparing with the resin bolt, the hydraulic expansion bolt has different anchoring mechanism and application advantage. According to the working mechanism of the hydraulic expansion bolt, its anchoring force is expressed in four forms including support anchoring force, tension anchoring force, expansion anchoring force and tangent anchoring force, and their values can be obtained on the basis of each calculation formula. Among them, the expansion anchoring force, which is the unique anchoring force of the hydraulic expansion bolt, can provide confining pressure to increase the strength of rock. Aiming at solving the problem of stability control in the soft rock roadway in Jinbaotun Coal Mine which has a double layer of 40 U-type sheds and cannot provide enough resistance support to control floor heave, the study reveals the mechanism of floor heave in the soft rock roadway, and designs the reasonable support parameters of the hydraulic expansion bolts. The observed results of floor convergence indicate that the hydraulic expansion bolts can prevent the development and flow of the plastic zone in the floor rock to control floor heave. Research results enrich the control technology in the soft rock roadway. © 2013 Published by Elsevier B.V. on behalf of China University of Mining & Technology.


Zhou N.,China University of Mining and Technology | Zhou N.,Key Laboratory of Deep Coal Resource Mining | Jiang H.Q.,China University of Mining and Technology | Jiang H.Q.,Key Laboratory of Deep Coal Resource Mining | And 2 more authors.
Transactions of the Institutions of Mining and Metallurgy, Section A: Mining Technology | Year: 2013

To mine coal resources trapped under embankment dams safely and efficiently while, at the same time, disposing of waste rock, solid backfill mining has been proposed as a solution. The extreme value of dam deformation was obtained by analysing geological conditions in the area and structural characteristics of the dam. It was determined that the filling ratio of the working face and the equivalent mining height were the two key factors that control dam deformation. In addition, the extreme values of these two key factors varied with the distance between the working face and the embankment dam in a regular pattern. When mining was completed at the first working face in the pilot area, the maximum sink value of the dam was 42 mm, and the maximum horizontal strain was 0·16 mm m-1. Field demonstrations have shown that solid backfill mining is effective in controlling strata movement and surface deformation. © 2013 Institute of Materials, Minerals and Mining and The AusIMM.


Zhang J.,China University of Mining and Technology | Zhang J.,Key Laboratory of Deep Coal Resource Mining | Miao X.,China University of Mining and Technology | Miao X.,Key Laboratory of Deep Coal Resource Mining | And 4 more authors.
International Journal of Mining Science and Technology | Year: 2014

s Based on break characteristics of roofs in fully mechanized top-coal mining of thick shallow coal seams, a fracture mechanics model was built, and the criterion of crack propagation in the main roof was derived using the fracture mechanics theory. The relationships between the fracture length of the roof and the working resistance of the supports were discovered, and the correlations between the load on the overlying strata and the ratio of the crack's length to the thickness of the roof were obtained. Using a working face of Jindi Coal Mine, Xing county Shanxi province as an example, the relationships between the fracture length of the roof and the working resistance of the supports were analysed in detail. The results give a design basis in hydraulic top coal caving supports, which could provide useful references in the practical application. On-site experiment proves that the periodic weighting step interval of the caving face is 15-16 m, which is basically consistent with the theoretical analysis results, and indicates that the mechanized caving hydraulic support is capable of meeting the support requirements in the mining of a super-thick but shallowly buried coal seam. © 2014 Published by Elsevier B.V. on behalf of China University of Mining & Technology.


Jiang H.,China University of Mining and Technology | Miao X.,China University of Mining and Technology | Zhang J.,Key Laboratory of Deep Coal Resource Mining | Liu S.,Key Laboratory of Deep Coal Resource Mining
International Journal of Mining Science and Technology | Year: 2016

Based upon characteristic movement features of the overlying strata in solid backfill mining and in-situ observations, an associated model representing a roadway support system has been developed. Based on the Winkler foundation and beam model, the current study presents a static analysis of the model, thus permitting acquisition of a theoretical formula pertaining to roof convergence. Through use of working face 6304-1 (Jisan Colliery) as the research setting, the association between roof convergence magnitude and both packwall strength and width have been elucidated. Based upon observed conditions at the working face, realistic packwall parameters have been formulated, with numerical simulation results and field application results indicating that design parameters garnered from the developed formula successfully adapted to local geological movement and deformation. Accordingly, roadway deformation was shown to be within the permissible range, thus satisfying mine production requirements. The proposed method in the current study may give a design basis for pack design in the context of SBM under similar conditions. © 2016.


Deng X.,China University of Mining and Technology | Zhang J.,China University of Mining and Technology | Kang T.,Key Laboratory of Deep Coal Resource Mining | Han X.,Key Laboratory of Deep Coal Resource Mining
International Journal of Mining Science and Technology | Year: 2016

Based on the character of upward slicing backfilling mining and the condition of Gonggeyingzi coal mine in Inner Mongolia, this paper describes the studies of the strata behavior and the stress distribution in the process of backfilling mining in extra-thick coal seams. This was achieved by setting up and analyzing the elastic foundation beam model using the ABAQUS software. The results show that: (1) With the gradual mining of different slices, the roof appears to bend continuously but does not break. The vertical stress in the roof decreases and the decreasing amplitude reduces, while the tensile stress in the roof grows with the mining slices and the maximum tensile stress will not exceed the allowable tensile stress. (2) The front vertical stress at the working face exceeds the rear vertical stress and both show a trend of decrease with decreasing amplitude of decrease. (3) The slices mined early have more influence on the surrounding rock than the later ones. Similarly, the strata behavior experiences the same trend. The field measured data show that the roof does not break during the mining process, which is consistent with the conclusion. © 2016.


Zhang J.,China University of Mining and Technology | Zhang J.,Key Laboratory of Deep Coal Resource Mining | Jiang H.,China University of Mining and Technology | Jiang H.,Key Laboratory of Deep Coal Resource Mining | And 3 more authors.
Mine Water and the Environment | Year: 2014

Numerous water inrush disasters have been associated with Chinese coal mines over the past 30 years. Accordingly, solid backfill mining (SBM) has been widely adopted to extract coal resources from beneath aquifers to reduce the magnitude and scope of overburden failure. Therefore, accurate determination of the height of the water-conducting zone associated with SBM is particularly important. The primary factors influencing development of water-conducting zones within solid backfill mines have been quantified in the current study, based on overburden movement and deformation characteristics. Numerical simulation has been used to evaluate the height of water conducting zones with respect to mine heights and backfill ratios. The results have been analyzed via multiple regression, leading to the development of a predictive equation. Field trials undertaken as part of the current study indicate a high level of accuracy with the developed equation. © 2014, Springer-Verlag Berlin Heidelberg.


Wu R.,Key Laboratory of Deep Coal Resource Mining | Xu J.H.,Key Laboratory of Deep Coal Resource Mining | Li C.,Key Laboratory of Deep Coal Resource Mining | Wang Z.L.,Key Laboratory of Deep Coal Resource Mining | Qin S.,Key Laboratory of Deep Coal Resource Mining
Engineering Analysis with Boundary Elements | Year: 2015

Mine roof, is a stiff rock strata, located on the top of coal seam, which can prevent the deformation and control the stability of coal roadway after the coal roadway is tunneled, so mine roof is one of the most important structures in coal mining engineering. In this paper, mine roof is treated as elastic plate, which is studied thoroughly at the theoretical level. Based on the mechanical models of plane and stress analysis for elastic roof, using the boundary integral equation which is obtained by the natural boundary reduction, this paper obtains stress functions of elastic half roof, as well as the analytical and numerical solutions to the each stress field functions. We also analyze the rules of different stress distributions for roof under a concentrated force and a uniform distribution load, the results of calculation show uniformity of the stress distribution. In order to research the mine roof deformation law, Mohr-Coulomb model is established to describe the deformation behavior of roof surrounding rock, FLAC3D is also used to simulate the deformation of roof after the coal roadway is tunneled under different length of coal roadway excavation. The comparison result between BEM solution and FLAC3D simulation shows advantages to solve the problem by boundary element method, and numerical simulation proves the deformation behavior of roof is influenced by the length of coal roadway excavation. © 2014 Elsevier Ltd.


Li T.,Key Laboratory of Deep Coal Resource Mining | Mu Z.,Key Laboratory of Deep Coal Resource Mining | Liu G.,Key Laboratory of Deep Coal Resource Mining | Du J.,Key Laboratory of Deep Coal Resource Mining | Lu H.,Key Laboratory of Deep Coal Resource Mining
International Journal of Mining Science and Technology | Year: 2016

In order to explore the influence of coal mining disturbance on the rockburst occurring in fault zone, this research constructed a mechanical model for the evolution of fault stress, and analyzed the influence of the ratio of horizontal stress to vertical stress on the stability of fault, and the spatial distribution of the stress in fault zone as well as its evolution rule. Furthermore, the rockburst danger at different spatial areas of fault zone was predicated. Results show that: when both sides of the working face are mined out, the fault zone in the working face presents greater horizontal and vertical stresses at its boundaries but exhibits smaller stresses in its middle section; however, the ratio of horizontal stress to vertical stress is found to be greater at middle section and smaller at boundaries. As the working face advances towards the fault, the horizontal and vertical stresses of the fault firstly increases and then decreases; conversely, the ratio of horizontal stress to vertical stress keeps decreasing all the time. Therefore, if the fault zones are closer to the goaf and the coal wall, the stress ratio will be smaller, and the fault slip will be more prone to occur, therefore rockburst danger will be greater. This research results provide guidance for the rockburst prevention and hazard control of the coal mining in fault zone. © 2016.

Loading Key Laboratory of Deep Coal Resource Mining collaborators
Loading Key Laboratory of Deep Coal Resource Mining collaborators