Influence of stiffness softening of dynamic pressure roadway two sides on roof deformation

Abstract

In order to clarify the influence of dynamic pressure roadway two sides stiffness softening on roof deformation, the geology and mining conditions of 3405 haulage roadway in Dayang Coal Mine are taken as the engineering background. Based on elastic foundation beam, limit equilibrium zone theory and in-situ monitoring, the difference of roof displacement with and without considering the deterioration of coal elastic modulus in the limit equilibrium zone of two sides is discussed. The results show that the maximum roof displacement is 138 mm and 267 mm respectively before and after the deterioration of coal elastic modulus. After considering the deterioration of elastic modulus, the average error between calculated and measured results of roof deformation is reduced by 45.9%. The roof displacement decreases exponentially with the decrease of the deterioration degree of the elastic modulus, and increases logarithmically with the increase of the width of the limit equilibrium zone. The excavation disturbance leads to the development of cracks in the two sides, and the equivalent stiffness decreases, the roof displacement increases due to the weakening of the supporting capacity of the two sides. Therefore, it is necessary to consider the influence of the deterioration of the elastic modulus of coal in the two sides limit equilibrium zone in the design of the roadway roof deformation support.

Keywords

• roof displacement
• elastic foundation beam
• elastic modulus
• excavation disturbance
• limit equilibrium zone