Quantitative analysis of parameters' influence on the stability of coal roadway clamped by upper and lower soft rock with extra thickness

Abstract

In this paper, a physical model of coal roadway which is clamped by upper and lower soft rock with extra thickness was built according to the characteristics of soft rock strata in china's western mining area. Then, a series of orthogonal numerical experiments were carried out by selecting the strength and stiffness parameters of soft rock and coal seam as well as the in situ stress of soft rock strata as experimental factors and roadway displacements (convergence displacements of sides, displacement of roof to floor) as experimental indexes. By constructing the F statistics with different inspection levels, evaluation method for influence of the experimental factors on stability indexes were defined. Thus, influence degrees of specified parameters on the stability of roadway were divided into five classes as follows: highly significant influence, significant influence, relatively significant influence, little significant influence, and no influence respectively which realize the quantitative analysis of the influence degrees of experimental factors. The finite element calculation results showed that main failure mode of coal roadway that usually showed as tension failure of coal seam in roof and deformation factors of coal seam had the most remarkable effect on roadway displacements. The conclusions provide theoretical basis for further analysis of the mechanism of "roof burst" in roadway maintenance.