| Physically similar simulation is an important method to study the key scientific issues of safe coal and gas mining.Similar materials are the key to physical simulation.The similarity criterion is the theoretical basis of the physical simulation and is the basic premise for the development of similar materials to determine experimental conditions.Systematic summary of research results and recent progress in recent years pointed out that the development of "solid-gas" coupling similar materials and its application in physical similarity simulation experiments are the focus of future research.It also provides the basis for carrying out the physical similarity simulation experiment of the pressure relief gas migration under the influence of mining.The "solid-gas" coupling model under triaxial conditions was established by combining the similarity theory,the control equation of overburden mining deformation field,and the control equation of gas seepage field.Sand aggregates were selected as similar materials,cement as a similar material binder,gypsum and starch as similar materials for gas barrier cements.Using the developed experimental system of mechanics and permeability characteristics of conventional three-axis "solid-gas" coupling similar materials,the axial stress-strain variation law,axial stress peak and axial stress gradient change law of similar materials were analyzed.The law of the axial strain-permeability,permeability change under different inlet pressures,and the influence of different ratios on the permeability of similar materials were studied.Through the self-developed conventional triaxial "solid-gas" coupling similar material characteristics experimental bench,the similar material test of the characteristics of the experiment,can well reflect the similar material "solid-gas" coupled permeability mechanics and permeability characteristics.It provides a theoretical basis for the laboratory to carry out three-dimensional solid-gas coupled physical simulation experiments. |
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