The deformation law of the surrounding rock in deep mining roadways under the influence of multi-factors and the control countermeasures

According to the common failures of support system in the deep mining roadway 13-1 of Huainan Mine and section shrinkage rate reaching 58.1% in some roadways under high horizontal stress, the influence of burial depth, section shape and size, wall length, mining height, and support length on deformation and destruction of the surrounding rock in deep mining roadways was studied through field test, model simulation, numerical simulation, and theoretical analysis, and the control principles were proposed of optimization of excavating direction, sidewall strengthening and roof support, section optimization, and roof partition support and gradient strengthening. A true triaxial model test has found that with the increase of burial depth and dynamic stress, radial strain of the surrounding rock turns from tensile strain in shallow part and zero strain in the deep part to alternant distribution of tensile and compression strain, and then to nonlinear large strain. Compared with small rectangle section, the convergence of the surrounding rock in roadway with large section was 0.45 m more, but the shrinkage rate reduced by 7.2%. The sequence of main influence factors affecting deformation of surrounding rock in the deep roadway 13-1 were determined through numerical stimulation: mining depth>mining height> support length>wall length; the convergence in both roof to floor and two sidewalls reaches 650 mm when the burial depth is 900 m. The integrated control countermeasures were put forward as follows: deformation reserved at large section, optimization of the straight wall flat arch section, strengthening the support at sidewalls, roof controlled by advanced self-walking support, and in-time reinforcement of signal column. The engineering practice results have shown that those integrated technologies can effectively control the deformation of gateways surrounding rock, and ensure the safety of gateways during its service. © 2017, Editorial Board of Journal of Mining & Safety Engineering. All right reserved.