| The gas disasters often happened in Chinese coal mine, and the situation is very serious. Drilling was a necessary technical mean for gas extraction and gas control, the quality of drilling affected hole sealing function directly. In our country, the quality of hole sealing materials are unsatisfactory, which impacted on the efficiency of gas drainage drilling and the safety of coal mine production. At present, cement-based material is one of most widely used sealing materials in coal mine of our country. So modification cement-based sealing material will improve the quality of drilling sealed situation largely, and have very important realistic significance. This paper mainly conducted three experiments and main results as follows:For the problem that early strength was low and the solidification time of hole sealing material was long under the condition of high humidity environment in coal mine, a new type of lithium sulfate compound hardening accelerating admixture were studied in this thesis. By the test method of SEM and DTA, the effect of different components and additive amounts of composite-agents on the early strength performance of hole sealing cement was studied through orthogonal experiments. When the additive amount of composite-agents was1.3%of the total mass of hole sealing materials, and its components was1.0%lithium sulfate,0.3%polycarboxylate and0.03%triethanolamine, the Id compressive strength was increased to556%. Lithium sulfate early strength agent didn’t change the types of hydration products, but it can promote fracture of the cement hydration film, accelerate the end of the induction period, and improve the early strength of cement.Aiming at the problem of cement hole sealing material often drying shrinkage cracks, cement expansion admixture were modified. Based on the microcapsule packages technology and idea of "strength-expansion coordinated development". Concrete expansion agent microcapsules were synthesized by oil phase separation using EC as shell material under the condition of water bath temperature75℃and control mass ratio of core material/shell material is5:1. Expansion rate final value of microcapsule group is relatively baseline group increased to25.58‰. By means of SEM, XRD and other test means, microcapsule and the microstructure of the modified cement hydration products were analyzed. The results show that the slow controlled release of the expansion agent ethyl cellulose membrane layers involved in hydration reaction, and the inflation can be used reasonably.In order to improve the shock resistance of cement hole sealing material for deep hole pre-splitting blasting, using water-based epoxy resin modified cement hole sealing. By means of SEM, the experimental results show that when water-based epoxy resin E-51appropriate dosage was10%, the shock resistance of experimental group increased by2.25times compared with blank group. Epoxy resin formed condensate in cement environment, which improved the ability of bond between all parts of the cementThe new multifunction hole sealing material was compound early strength agent and cement expansion agent and water-based epoxy resin, the hole sealing material components was100%cement＋60%water+1.0%lithium sulfate+O.3%polycarboxylate+0.03%triethanolamine+15%inflating microcapsules+10%water-based epoxy resin+5%curing agent This new multifunction hole sealing material1d compressive strength was increased to226%, expansion rate final value increased to23.8%o, shock resistance increased to200%. |
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