Advanced Materials Research Vols. 255-260

Abstract: In order to get the mechanical parameters of deep rock for the Fushun mining area, some mechanical properties tests of rock prepared from the drill core and trial adit were carried out. The complex mechanical parameters of rock mass were proposed by inversion of B-P neural network method with intruding the uniformity design theory. The deep rock parameters were amended and correction factor was proposed by according to geostress test and high confining pressure triaxial compression test.

Abstract: The goal of this paper is instructing the freezing construction scheme of alluvium of wind well in a mine. Through making scheme, designing cooling system and in-situ measuring frozen wall, succeed experiences of passing the expanded clay seam smoothly were achieved. It is hoped that the practical experiences will be reference to constructing mine in the analogous ground.

Abstract: Based on the complicated geological conditions of coal seam in Xuandong Coal Mine, such as deep burial depth, high gas content, magmatic rock intrusion and so on, the distribution regularities of magmatic rock, gas and geological structures were analyzed and studied. Combining with the practical situation of the dynamic disaster and phenomenon during the mining, the dangerous zones of coal and gas outburst were predicted and regional divided. The research results would have certain significance of practical guide to the outburst prevention and disaster reduction.

Abstract: Based on the big thickness, low stiffiness and other characters of No. 8 coal seam in Huaibei mining area, the moving laws of top coal seam and roof, and distribution law of ground pressure were studied under the fully mechanized top coal caving. The research methods included working resistance observation of hydraulic supports in working face, deformation observation of stope roadways and deeper base point observation in roof and top coal. The results show that, in the thick and soft coal seams, the influence coverage of mining ground pressure in fully mechanized top coal caving face is much wider than that in the working face with general mining technology, but the intensity of pressure is much lower.

Abstract: The instability identification of goaf risky is an important work in the mine engineering. Based on distance discriminant analysis, a method to identify the instability of goaf risky in mines was presented in this paper. Nine factors influencing the stability of goaf risky, including uniaxial compressive strength of rock, elastic modulus of rock, rock quality designation (RQD), area ration of pillar, ratio of width to height of pillar, depth of ore body, volume of goaf, dip of ore body and area of goaf, were selected as discriminant indexes in the stability analysis of goaf. The actual data of 40 goafs were used as training samples to establish a discriminant analysis model to identify the stability of goaf. The results show that this discriminant analysis model has high precision and misdiscriminant ratio is 0.025 in re-substitution process. The instability identification of a metal mine was discriminanted by using this model and the identification result is identical with that of practical situation.

Abstract: The coal mining mode of paste-like fill shows the connotation and characteristics of green mining both in the filling materials and mining backfill technology. Combined with the practical situation of colliery, some main components of the coal mining mode of paste-like fill are introduced emphatically, such as the cemented filling material, the preparation and transportation of filling materials, and filling technology at working face; the application prospects on mining with paste-like fill are analyzed.

Abstract: Since deformations of tunnel nearly mined area are larger, the reasonable support is very important. According to a side working face tunnel nearly mined area in one Mine, FLAC 2D was applied to numerical analyze on two type bolt net supported tunnel of “short bolt and long anchor cable” and “full anchor cable”. The results showed as follows: (1) plastic region of surrounding rock relatively large, which supported by short bolt and long anchor cable. Displacement reaches 27cm, the effect of this type supporting not significant; (2) The supporting of full anchor cable can effectively control deformation of tunnel, displacement less than 5cm, plastic region of surrounding rock also less than 2.3m. So, the supporting of full anchor cable can meet operating requirements.

Abstract: Jinchuan nickel mine is the largest cut-and fill mining mine in China. After keep successive mining for nearly twenty years, it appeared serious ground fissures. A major thrust of this paper is to discuss the distribution features, deformation regularities, development tendency and formation mechanisms of ground fissures based on long-term subsidence monitoring and investigation. The results showed that large-scale ground subsidence basin has been developed in the mine area, and the ground fissures mainly scattered in the tensile zone of the subsidence basin. Besides, ground fissures have the features of compressive shear or tensile mechanical properties and zonary pattern. Unfortunately, with the mining scale keep expanding, both the quantity and width of the ground fissures increased rapidly. This will be unfavourable to safety of mining and engineering facilities. Therefore, strengthened monitoring and prevention works are essentially important to the similar mines which designed with cut-and-fill mining method.

Abstract: Coal floor water inrush is the reason that the deformation and failure of rock strata in floor is induced by mining stress, cracks gradually develop, grow and accumulate, catastrophe result in forming water inrush passages, finally floor water inrush occurs. Interactions of adjacent damage element and long range correlation in coal floor are simulated by pattern dynamics. The evolution process of floor cracks is simulated by the change of element state, and some criteria are given to judge if the floor will fracture with the change of element state. The obvious characteristics of evolution process of floor cracks are progressive, and cracks make order-disorder distribution at different scales that evolve into order distribution, and finally form water inrush passages.

Abstract: The similar material model method is used to simulate to the movement of cover rock and ground which is caused by mining underground coal, the substance of deformation and failure law of similar material model method is that artificial materials which are used in the experiment have similar physical and mechanical properties as archetype, affinity constants of geometry, movement and force are used as similarity index and criteria in the simulation experiment as the most important factors. The prototype model is made into a certain proportion model in reduction, and the initial state and boundary conditions of model must be similar as archetype. Then exploit the simulating model, the regular patterns of fault destruction, curve, movement and deformation of cover rock can be discovered in the process of exploiting the simulating model, and the movement and deformation of the surface and its sphere of influence can also be got. Finally the observations of model can be calculated and projections up to the prototype by the similarity index, so the most important regular pattern of the prototype can be got.