Numerical Analysis on Roof Raining Affected to Surrounding Rock Deformation of Mine Gateway

Abstract：In order to solve the easy roof falling problem affected by the roof raining of the mine gateway, a numerical simulation method was applied to study the surrounding rock stressed, deformation and failure feature variations under the different conditions with no roof raining at the initial gateway driving and with roof raining at the late gateway driving. The results showed that water would have remarkable influences to the rock property and to the stress conditions. Affected by the roof raining ~ the surrounding rock would have swelling deform- ation, stress increased and stress concentrated zone expanded. When the surrounding rock was with water, the strength of the rock would be decreased. Affected by the stress increased and the strength decreased, the rock deformation would be remarkably increased and the failure phenomenon would be occurred. Based on the numerical calculation results of the actual physical mechanics parameters in a mine of Ordos Mining Area, when the roof was raining, the vertical stress and horizontal stress would be individually increased by 50% and 13.8% than the dry roof. The raining roof subsidence value would be increased by 450% than the dry roof and the raining roof plastic zone would be expanded by 2. 3 times than the dry roof. The grouting reinforcement or shield support mode timely conducted in the gateway could effectively reduce the roof falling accident occurred.