矿用自膨胀封孔材料的制备及性能研究

发布时间：2018-06-12 11:35

本文选题：瓦斯抽采封孔 + 自膨胀封孔材料　；参考：《安徽理工大学》2017年硕士论文

【摘要】：瓦斯抽采作为煤矿瓦斯治理最根本最有效的方法,从上世纪50年代一直沿用至今。但我国绝大多数矿井存在瓦斯抽采效率不达标的问题。瓦斯抽采效率不达标的关键因素之一就是封孔质量,而封孔质量好坏又取决于封孔材料。本文以煤矿瓦斯抽采钻孔的封孔材料为研究对象,针对现有封孔材料存在凝结时间长、早期强度低、容易开裂等问题,对封孔材料的复合配方进行研制并测定相关性能。首先,以水泥为主,与石膏、氧化钙、膨润土、二氧化硅等多种添加剂复合,研制出了一种新型矿用自膨胀封孔材料,并通过实验研究给出了该材料的8组配方配比。在此基础上,采用线性权重法对这8组配方制备成的封孔材料的膨胀率、渗透率、泌水率、1d抗压强度、流动性进行测定,并对所占权重进行排名。结果显示,配方A的所得权重最大,即配方A为最优配比,水泥、石膏、氧化钙、膨润土、二氧化硅、纤维素分别为46.5%、30%、20%、0.8%、5.5%、0.2%。然后,利用X射线衍射仪和同步热分析仪分别分析分析配方A水化产物的晶体和水化产物的分解过程,得到不同龄期下的XRD图谱和水化产物的种类,从而掌握其早强速凝的机理。一方面,各组分相互作用,水化过程得到促进,钙矾石不断生成并相互交错搭连,形成稳定的骨架结构;另一方面,抑制膨胀剂的水化速度,减少裂隙产生,并且由二氧化硅去填充所产生的微小裂隙,使得整体的水化产物既发生膨胀又致密,增强骨架。接着,对自膨胀封孔材料的渗透特性和力学特性进行研究。结果表明:渗透率随着龄期的增加而降低并趋于稳定;在不同进口压力条件下,渗透率随着进口压力的增大而呈现先较小后增大的趋势,在0.5MPa至0.6MPa时渗透率最低;在不同的围压下,其渗透率随着围压的增大而减小。其静态抗压强度相比普通水泥,提高幅度明显。1d后抗压强度是普通水泥的3.22倍,28d后仍达1.59倍,具有稳定的强度表现。采用SHPB实验系统进行单轴冲击压缩实验,获得了实验波形,处理数据后得到应力应变曲线,表明材料具有明显的应力硬化特性。最后,采用自膨胀封孔材料对五轮山煤矿瓦斯抽采钻孔进行实验,现场应用效果表明,该材料封孔效果显著,优点突出,使用后的单孔瓦斯抽采浓度较普通水泥提高3%～35%,是一种具有广阔应用前景和推广价值的新型矿用封孔材料。
[Abstract]:Gas drainage, as the most fundamental and effective method for gas control in coal mines, has been used since 1950's. But most of the mines in our country have the problem that the efficiency of gas drainage is not up to the standard. The sealing quality is one of the key factors that the gas drainage efficiency is not up to standard, and the sealing quality depends on the sealing material. Aiming at the problems of long setting time, low early strength and easy cracking in the existing sealing materials, the compound formula of sealing materials was developed and the related properties were measured. Firstly, a new type of mineral self-expansion sealing material was developed by combining cement with gypsum, calcium oxide, bentonite, silica and other additives. On this basis, the expansion ratio, permeability, bleeding rate of 1 day compressive strength and fluidity of the sealing materials were determined by linear weight method, and the weight was ranked. The results showed that the weight of formula A was the largest, that is, formula A was the best proportion, cement, gypsum, calcium oxide, bentonite, silicon dioxide and cellulose were 46.5%. Then, X-ray diffractometer and synchronous thermal analyzer were used to analyze the crystal and the decomposition process of hydration products of formula A, respectively, and the XRD patterns and kinds of hydration products at different ages were obtained. Therefore, the mechanism of its early strong solidification can be grasped. On the one hand, the interaction of components promotes the hydration process, and ettringite is constantly formed and interlaced with each other to form a stable skeleton structure; on the other hand, it inhibits the hydration rate of the expansion agent and reduces the formation of fissures. And the tiny fissure produced by silicon dioxide depadding makes the whole hydration product expand and dense and strengthen the skeleton. Then, the permeability and mechanical properties of self-expansion sealing materials are studied. The results show that the permeability decreases and tends to be stable with the increase of age, the permeability decreases first and then increases with the increase of inlet pressure under different inlet pressure, and the permeability is the lowest in the range of 0.5 MPA to 0.6 MPA. At different confining pressures, the permeability decreases with the increase of confining pressure. The static compressive strength of the cement is 1.59 times higher than that of the ordinary cement. The compressive strength of the cement is 3.22 times than that of the ordinary cement for 28 days. The strength of the cement is stable. The uniaxial shock compression experiment was carried out with SHPB system. The experimental waveform was obtained, and the stress-strain curve was obtained after processing the data, which indicated that the material had obvious stress-hardening characteristics. Finally, the self-expansion hole sealing material is used to test the gas drainage borehole in Wulunshan Coal Mine. The field application results show that the sealing effect of the material is remarkable, and the advantages of the material are outstanding. Compared with ordinary cement, the concentration of single hole gas drainage is increased by 3% 35%, which is a new type of sealing material with wide application prospect and popularizing value.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD712.6

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