Research on high-efficiency sealing material and technology of coal roof deep-hole pre-splitting blasting

Based on the difficulty of sealing, low sealing efficiency, and high labor intensity in the process of deep hole pre-splitting blasting of the coal roof with traditional sealing materials, a high-efficiency sealing material was proposed. The material has the characteristics of short curing time, high early strength, and strong pump ability, the initial setting time of the material is 3.0min, and the curing time is 8.0min; The reaction exothermic temperature is not higher than 70 ℃, lower than the ignition temperature of the electric detonator; And the compressive strength of 0.5 h is 5.96 MPa, which is nearly 25 times higher than the 0.232 MPa of clay stemming material;  By analyzing the hole sealing mechanism of grouting materials, it is determined that the compressive strength of efficient hole sealing materials meets the requirements of hole sealing.; In order to further study the sealing strength of high-efficiency sealing materials, the sealing strength of high-efficiency sealing materials under static load was tested by the RMT-150 rock mechanics testing system with the comparison of clay mud materials; At the same time, according to the characteristics of the material, a set of accurate, easy-to-operate and efficient sealing technology was designed and field engineering tests were carried out. The results show that: under static compressive load, the compressive resistance of the sealing material and the residual pressure of the material increase with the increase of the sealing length, and the compressive load strength of the high-efficiency sealing material is much greater than that of the clay mud material; With the same length of sealing hole, the sealing strength of high-efficiency sealing material is much higher than that of the clay mud material.. Single hole sealing time is 15 min, sealing 0.5 h can be blasted; After blasting, the roof integrity is relatively good, co concentration is 5−20, in line with the blasting safety requirements.. It shows that High efficiency hole sealing material blasting hole sealing not only has a good hole sealing effect, but also realize blasting hole sealing mechanized operation, solve the problem of roof deep hole sealing, greatly improve the efficiency of blasting hole sealing, compared with the traditional hole sealing process has made great progress.