Application Study on Pre-stressed Full Length Bolting Powerful Support System

Abstract：In order to solve the problems existed in the conventional bolt support system under the complicated and difficult mine roadway,the different bolting methods affected to the mine roadway support were analyzed theoretically.The advantages of the full length pre-stressed bolting with the end bolting and full bolting were obtained.The pre-stressed full length bolt could have a pre-tightened torque on the long length bolt bar and the sensitivity to the surrounding rock separation and displacement would be increased.The numerical simulation calculation method was applied to analyze the different bolting mode affected to the additional stress filed of the bolt support.The effective access to improve the expansion results of the pre-stressed full length anchored bolt was first to have a pre-stress and then to have the anchoring agent for consolidation.An industrial trial was conducted in the underground mine of Luan Mining Area.The bolt stressed distribution and variation monitored and measured under the pre-stressed full length anchoring status.The bolt and anchor was stressed in stable basically.The max stressed force of the bolt was 122 kN and the max stressed force of the anchor was 387 kN.The mine pressure monitoring and measuring data showed that the pre-stressed bolting powerful support system would be better than the conventional support and could effectively control the deformation of the surrounding rock with a good support effect.