Advanced Materials Research Vols. 1010-1012

Abstract: In order to study the mechanism of dynamic disaster on gassy coal and realize the monitoring and prediction, with the Didao mine as an example, this paper set up the thermal fluid-solid three field couple mathematical models of driving face and comparative analyzed the mathematical models between couple and not couple by using the software comsol. The study result shows that it has a swift response, a close connection and a shorter time in the formation of o-ring, when it is the thermal fluid-solid three field couple.

Abstract: COMSOL software was used in the paper for numerical simulation of excavation face and study stress, gas pressure, the gas seepage velocity, displacement and the change of temperature as well as to the effect of dynamic disaster under different temperature conditions. The results show that the speed of gas pressure to reduce slowed, the gas pressure near the working face gradient increasing with the increase of temperature; the face gas concentration changed not significantly because of the change of temperature under the condition of the temperature change is not big; seepage velocity varies was not obvious under the condition of other conditions don't change, because the viscosity coefficient of the change was not obvious.

Abstract: Based on the concept of cleaner production, the feasibility of application of the flue gas in mine mouth power to fire prevention and extinguishing in goaf was numerically studied by taking the mechanized caving mining face 11-214 of Caocun coal mine as the example. The heterogeneity porosity and multi-component gas transport equations were introduced into the mathematical model. The calculated results showed that the area of “spontaneous combustion zone” turn small obviously in goaf and the maximum width of “spontaneous combustion zone” in goaf decreased from 78m to 9.5m after injecting the flue gas. At the same time, the sink terms of oxygen consumption was formed in the port of gas injection. The migration law of flue gas showed that the numerical calculation of goaf should select the different computation model based on the judgment basis of Reynolds number. Through the continuous monitoring of the migration of flue gas at different locations in goaf, the reasonable parameters of flue gas injection was obtained for high efficient fire prevention .

Abstract: RBF neural network is a well-behaved feed forward network and with it the nonlinear evolution of slope stability could be obtained by learning the sample repeatedly, which really possesses a better approximation and globe optimum features. The prediction model of slope stability based on RBF neural network has the advantages of simple structure, fast learning and precise forecasting. Through the calculation of three engineering examples in Bayan Obo east mine, the analysis method of slope stability based on RBF neural network is proved to be functional and effective.

Abstract: Based on interval arrangement characteristics of the mined branch roadways and pillars in continuous miner filling mining gob,the cemented filling mining thought which divided mining and filling both into two stages was put forward.The first stage was mining branch roadways and then filling gob with cemented materials in time, and the second stage was mining pillars and filling gob with the first stage filling body support when it meet designed strength. Industrial field test showed that branch roadways were smoothly mined and filled, filling body strength meet demand and pillars were safety mined out.Continuous miner filling mining technology could reache high production efficiency based on advantages of mining and filling parallel operation and filling spaces constructing easily.

Abstract: In order to reduce the cost of backfilling materials in north-west mining area, the feasibility of making the loess as backfilling material in coal mine was discussed in this paper, an orthogonal experiment were conducted and the ratio of backfilling material is gained by author. The experiment was based on the material as main material: loess with fly ash, auxiliary material:cement with lime and other additive agent. According to the mechanism of alkali excitation on the potential activity of the fly ash , a four levels and five factors experiment was conducted by using the orthogonal principle, to analyze the influence of various factors on the main indicators of material specimen, the new material ratio that meet the requirements of backfilling is obtained. Experimental results indicate that: it's feasible to make the loess with fly ash as filling material in coal mine, the appropriate slurry concentration is 60% ~ 65% and the optimal range of the weight ratio of loess with fly ash is 1:1.5~1:3, the optimal range of the weight ratio of auxiliary materials with solid material is 30%~33% and 5%～7% of additive dosage respectively, the appropriate curing time is 28 days.

Abstract: Stress wave propagation effect and failure characteristics were studied by one-stage light-gas gun induced-plate impact experiment technology on limestone. The results show that dispersion effect and attenuation character are existed in impacting rock; failure division properties are analyzed by splitting cut observation, the results show that the failure specimen can be divided by three different failure divisions which are head failure zone, middle tension-compression failure zone and tail fracture failure zone. On this basis, impact-damaged process of rock is numerically simulated to analyze impact-damaged mechanism of limestone specimens.

Abstract: Based on a deep understanding of FLAC 3D numerical simulation software and the solid-liquid coupling theory and calculation method, this paper established a mining three-dimensional mechanical model under the pressurized water .Using the numerical simulation method, this paper systematically analysis deformation Laws of stress distribution of mining floor, bottom stress, its plastic zone and floor failure depth. By analyzing water inrush flow-solid coupling seepage problem under the conditions of coal mining, and compares with relevant information, verify the rationality of the existing theories and engineering measures, provide a theoretical basis for seeking security and economic exploitation of technical measures.

Abstract: This paper simulates the alternation of the maximum explosion overpressure on the different condition of the concentration based on the fluent software. The results show the maximum explosion overpressure increases in the earlier stage and then decreases in the later stage because of the different flammable gas concentration: the maximum explosion overpressure enhanced in 6% gas concentration and drops in 12% gas concentration; it augments in 6% gas concentration and drops in 12% gas concentration with the joining of the hydrogen; the explosion pressure peaked just at the 9% concentration of the flammable gas.

Abstract: By theoretical calculations, numerical simulation and field monitoring methods to analyze the stress distribution and the extent of damage of coal pillar determine a reasonable size is about 10m, can improve the recovery rate of coal resources, and to ensure the roadway stability. 10m pillar coal resources compared with the previous 20m pillar recovery increased by about 5.5%, and created tremendous economic benefits of the mine.