| Aiming at the problems of traditional blasting sealing materials in the roof deep-hole pre-splitting blasting project,such as difficulty in sealing,poor effect and low efficiency,a high-efficiency blasting sealing material and technology are proposed.The sealing material has the properties of quick setting,early strength and strong pumpability.In order to determine the sealing strength of the quick sealing material,taking clay materials as a comparison,using theoretical analysis,laboratory tests and field applications to study the basic properties,sealing strength and sealing technology of high-efficiency sealing materials.The main research results are as follows:(1)According to the physical and mechanical model of the sealing material,The greater the compressive strength of the sealing material and the greater the pressure acting on the material,the greater the friction resistance of the sealing material and the better the sealing effect.The initial setting time of the fast sealing material is 3.0min～10.0min,and the final setting time is 8.0min～20.0min When the water-cement ratio is 0.8:1,the maximum reaction exothermic temperature within 1.0h is 65.6℃,which is lower than the ignition temperature of electric detonator,and it can be used safely in coal mine working face.And the compressive strength of the efficient hole sealing material is much higher than that of the stemming material.(2)Taking stemming materials as a comparison,the sealing strength of high-efficiency sealing materials is studied under the action of dynamic and static loads.The results show that: under static load compression,when the age exceeds 40.0 minutes and the water-cement ratio is between 0.8:1 and 1.2:1,the sealing strength of the high-efficiency sealing material is higher than that of the blasting mud material,which meets the needs of blasting.But under the impact of dynamic load,when the age is 60.0 minutes and the water-cement ratio is lower than 0.8:1,the sealing strength of the high-efficiency sealing material is higher than that of the blasting cement material,which meets the blast sealing strength.Therefore,when the sealing length is the same,the sealing effect of the high-efficiency sealing material is better than that of the blasting mud material.(3)Because the existing process can not meet the characteristics of efficient sealing material such as short setting time,high early strength and strong pumping,a set of accurate,efficient and convenient sealing process is designed;The mechanized operation of blasting sealing hole is realized,and the problem of sealing hole by blasting deep hole of roof is solved,and the labor intensity is reduced and the work efficiency is improved.(4)According to the site engineering geological conditions,select reasonable hole sealing equipment to carry out field test;The test results show that the single-hole sealing time is 15.0min,sealing hole after 1.0h can meet the blasting requirements;When the explosive detonated,there was no obvious crack in the roof;The sealing technology not only solves the problem of deep hole blasting and sealing of the roof,but also greatly improves the work efficiency,and has made great progress compared with the traditional sealing technology. |
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