Study on pressure releasing technology with structural cracking made with deep borehole blasting

In order to solve the serious deformation problem of the front gateway occurred by the dynamic forward movement of the advance stress after the mining ter mination of the hard roof and high cutting coal mining face,the paper discussed the dynamic moving forward law of the advance support pressure and the stress distribution law of the fault structure and the paper held that the increased size of the protective coal pillar in the mining gateway could not effectively release the deformation of the fro nt gateway. With the redistribution law of the stress near the fault,the analogy analysis on the stress distribution features before and after the deep borehole blasting of the roof and the numerical simulation study,a new technology was provided to solve the surrounding rock stability lost of the front gateway after the mining terminated and was a structural cracking and pressure releasing technology with the deep boreholes. The results showed that the artificial structure cracking occurred by a deep borehole blast ing with a certain distance to the coal mining face could effectively interrupt the forward movement of the advance support pressure. The protective coal pillar with a with of 41 m from the pressure released blasting borehole exceeded the max influence distance of 40 m over the blasting itself. In comparison with no pressure released measure s conducted,the stress in 40 m front of the blasting borehole was reduced by 11% and could ensure the stability of the gateway. The structure cracking pressure released t echnology with the deep borehole blasting could provide a new idea and method to solve the stability lost of the gateway surrounding rock by the advance stress.