Research On Similarity Of Material And System For Coal And Gas Outburst Simulation Test

The coal and gas outburst similar simulation test is an effective way to study the mechanical mechanism in the process of coal and gas outburst. The paper studied the characteristics of outburst coal and coal and gas outburst, physical dimension of model and similar model, Mechanical loading system, similar material ratio method and press forming process of similar model, and so on. It provides similarity guarantees for similar simulation tests. The main conclusions are as follows:(1) Through the statistical analysis of coal and gas outburst of field data and the existing research results, it was obtained that the outburst coal seam has the characteristics of high damage degree of structure, large number of porosity and surface area, large gas adsorption and desorption properties, low permeability and strength; also, the coal and gas outburst has such characteristics which are different from other coal or rock dynamic disasters as hoe of small mouth and large cavity, dished out coal and rock, emission a large amount of gas.(2) Bsed on "Mechanical effect of the mechanism of coal and gas outburst theory", the similarity criterion of coal and gas outburst was deduced, and the consolidated similarity criterion of geometric similarity,load and material properties similarity, gas occurrence and emission similarity was obtained. It provides foundation for the study on similarities of materials and similar system of coal and gas outburst similar simulation test.(3) The physical dimension of typical coal and gas outburst was deduced, and it is 12.3m depth,6.5m width, and 0.68m diameter of outburst hole mouth. The similar simulation system such as physical dimension of model, loading capacity and stiffness of mechanical loading system, bearing capacity of sealing containing, and outburst mouth open method was also studied. The results guarantee the geometri similarity and mechanical loading similarity, and provided the guide for the similar test system constructure.(4) The coal, cement, activated charcoal, sand and wate were choiced as raw materials for similar material. Then the proportion relationship among uniaxial compressive strength, firmness coefficient, elastic modulus, density and other physical and mechanical properties and raw materials were studied with uniform test method. Through the similar material adsorption desorption parameter testing, permeability testing, and the study of the relationships between size, pressure keeping time and mechanical strength of similar material samples were also studied. So, the similar material ratio method and model making process were obtained. It provides similarities of material properties and movement for coal and gas outburst similar simulation test.(5) Numerical simulation models of solid gas coupling were established according to the coal and gas outburst similar model test system. Then the coal and gas outburst process of inoculation, occurrence, development and stopping, and the movment rule of coal and gas in the tunnel were simulated with RFPA2D Gas-Flow, Fluent software and test system. And variation rules of prominent parameters with time and space were obtained. The study verifies the similarity or test system and similar material, and provides guidance for similar simulation test of coal and gas outburst.