Deformation and failure law of coal roadway supported by concrete filled steel tube supports in Nanguan mine

Abstract

Taking the coal roadway in Nanguan mine of Fenxi mining area as the prototype, relying on the nested similarity simulation experimental system, the physical similarity model was established to study the stress distribution, displacement and deformation failure characteristics of the surrounding rock of coal roadway supported by concrete filled steel tube support.FLAC3D 5.0 software was used to establish the calculation model of concrete filled steel tube support roadway, which simulated the depth of 100 m to 1000 m respectively;the deformation and failure law of coal roadway and the characteristics of support stress were analyzed.The results showed that, concrete-filled steel tube support can improve the radial support pressure of roadway.At the initial stage of loading, the stability of roadway is maintained, however, with the increase of load, the convergence of sidewall is greater than that of roof and floor.Fissures first appear in the sidewall and develop to the roof and floor, then the sidewall and the roof are unstable successively.It can be seen that the sidewall is the weak link of support.Under the action of concrete filled steel tube support, the stress distribution on the roadway surface is serrated, which indicates that the support has an effective support range for surrounding rock, and the support between the supports is also the weak part of the support.The axial force and moment of the support casing are larger, and the casing is easy to be damaged, which leads to the loss of the bearing capacity of the support.It can be seen that the key to ensure the stability of concrete filled steel tube support in Nanguan mine is to control the deformation and failure of sidewall and support casing and to improve its strength.

Keywords

• concrete filled steel tube supports
• coal roadway
• surrounding rock deformation
• sidewall
• modeling experiment