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Wang Z.-L.,Beijing China Coal Mine Engineering Co.
Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys | Year: 2013

NiCrBSi coating was prepared on the surface of 45 steel with 5 kW TJ-HL-T5000 CO2 laser by powder metallurgy. The microstructure and properties of the cladding layer were characterized by SEM (scanning electron microscope), EDX (energy dispersive X-ray), XRD (X-ray diffraction). The microhardness and wear resistance of the laser cladding layer were examined by microhardness meter and M-200 ring-block wear tester. The results show that laser cladding layer with the good metallurgical bonding between the coating and substrate and dense, uniform, continuous and free of pores and cracks can be observed based on the optimized processing parameters. The microstructure of the cladding coating is mainly composed of dendrite γ-Ni, eutectic Ni3B, bulky particles CrB and dendrite Cr23C6 particles. The microhardness of the cladding coating (HV0.2)500~650 is approximately 2 times than that of the sub-strate (HV0.2)250, which is attributed to particle strengthening and grain-refining strengthening effects, greatly improving wear resistance of 45 steel.

Wang H.,Tiandi Science And Technology | Wang H.,Beijing China Coal Mine Engineering Co. | Wang H.,National Engineering Laboratory for Deep Shaft Construction Technology in Coal Mine
Progress in Civil, Architectural and Hydraulic Engineering - Selected Papers of the 4th International Conference on Civil, Architectural and Hydraulic Engineering, ICCAHE 2015 | Year: 2016

Analyzing water inrush risk and forecasting outflow rate of each workface is one of the important tasks of mine water prevention. 3229 working face in Tianzhu Coal Mine is partial below the Jinsha River. There are four aquifers above the 3229 working face, which are strong pore free aquifer of Quaternary (Q) alluvium, weak pore free aquifer of Early Cretaceous Hekou Group, weak pore-fissured confined aquifer of Late Jurassic Kushuixia Group, and pore-fissured confined aquifer of Middle Jurassic Yaojie Group. Therefore, it will be likely that water inrush will take place during the mining process. On the basis of fully analyzing the geological and hydrogeological data of mine field, adopting “Up Three Zone” Theory of coal seam roof (the caving zone, water flowing fractured zone and bending sinking zone), principles of hydrogeology and theory of ground surface strata movement law, and combining the research results of ground fissure, roof water inrush risk of 3229 working face was analyzed, and outflow rate was forecasted. The results show as follows: (1) Mining 3229 working face will probably lead to the extension of surface subsidence area to Jinsha River valley; (2) The maximum height of water flowing fractured zone is 107.48 m, so the water of Yaojie Formation aquifer will inrush the mined-out area of the working face; (3) The surface crack depth is less than 70 m, so the water of Jinsha River will not rush in the mined-out area of the working face; (4) The ordinary outflow rate of the working face is 13.60 m3/h, and the maximum outflow rate is 27.20 m3/h. It is proposed that the necessary water prevention and control measures be taken to ensure the safety in mining the working face. © 2016 Taylor & Francis Group, London.

Sun J.R.,Beijing China Coal Mine Engineering Co.
Advanced Materials Research | Year: 2014

The fuzzy drilling fluid can effectively solve the serious lost circulation problem in the surface layer, it can be used in the raise drilling. The fuzzy ball drilling fluid with the density of 0. 9g/cm3 was prepared in the laboratory. With the driving pressure increases, researchers do the plugging experiment with & without 0. 5MPa back pressure. The experiments show that in a back pressure condition, fuzzy ball drilling fluid can effectively plugging formation. Besides, fuzzy ball drilling fluid can effectively control the leakage without back pressure. In the process of GuiZhouLongAn raise boring, the surface layer of the hole leaked seriously with leak off rate of more than 40m3/h in the first 10m and once exceeded 100 m3/h. The field use Fuzzy ball drilling fluid on the well plugging. The circulation is rapidly established after the Fuzzy ball drilling fluid was injected into the well, and the leakage rate has been effectively controlled. In the raise drilling, the fuzzy ball drilling fluid can only control the leakage rate but can't seal the leakage formation. © (2014) Trans Tech Publications, Switzerland.

Cui H.,Beijing China Coal Mine Engineering Co. | Li D.-W.,Anhui University of Science and Technology | Wang R.-H.,Anhui University of Science and Technology
Applied Mechanics and Materials | Year: 2011

Through the large number uniaxial strength tests and the creep test tests of the artificially frozen soil of Cretaceous strata, we obtained that the frozen wall in Cretaceous strata met the Moore - Coulomb strength criterion, and the artificially frozen soil strength increased from 6.5MPa in -5 °C to 12.0MPa in -15 °C with the freezing temperature decreased, Poisson's ratio from 0.35 down to -5 °C -15 °C at 0.18. Using viscoelastic-plastic theory we got the deep frozen wall strength and thickness of the Bojiang - Haizi mine in Cretaceous strata, practice showed that: the design approach in this paper was reasonable. © (2011) Trans Tech Publications, Switzerland.

Cui H.,Beijing China Coal Mine Engineering Co. | Li D.-W.,Anhui University of Science and Technology | Wang R.-H.,Anhui University of Science and Technology
Applied Mechanics and Materials | Year: 2011

In order to obtain the internal frost heaving force development characteristics and change rule of frozen wall in the process of the formation and melting in cretaceous stratum, and then take analysis of mechanics features and safety evaluation of frozen wall, in a mine of Inner Mongolia, the field measurement research of internal and external frost heaving force and pore water pressure in the freeze-thaw process of frozen wall has been carried out. The measured results show that it formed uneven frost heaving stress in internal and external of frozen wall in freeze-thaw process, in the test the maximum of freezing pressure reach to 6.0MPa, it is 2.4 times of initial pressure in the layer; When the shaft excavated to test layer the freezing pressure reduced linearly, then the freezing pressure rebounded slightly when the wall was pouring, and finally the frost heaving force reduced to 0 when frozen wall melt, back to the pressure effected by soil and water. © (2011) Trans Tech Publications, Switzerland.

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