Establishment and analysis of similarity criteria for physical simulation of coal and gas outburst

Similarity criteria is the theoretical basis of physical simulation. It is the premise for developing similar ma- terials and determining the condition of experiment. Similarity criteria limits the development of physical simulation test of coal and gas outburst. Because the mechanical model of whole coal and gas outburst process has not been estab- lished,the similarity criterion was established using the gas-solid coupling model which could describe the embryonic stage. Similarity criterion above can ensure the deformation and failure law is similar. However,it cannot guarantee the coal and gas outburst phenomenon. This paper presented a method to derive the similarity criteria based on the energy model. A new similarity criterion was derived by similarity transformation. It can ensure that the perimental model is similar to the prototype in energy concentration,transfer and release. Combined the two groups of similarity criterion, on the basis of the similarity of the energy model and coal deformation and failure,a new similarity criteria of physical simulation on coal and gas outburst was established. Compared with the previous physical simulation results, it is proved that the similarity criterion is reasonable.