我国高瓦斯矿井占比高，煤层高瓦斯含量严重制约着矿井的安全高效生产。瓦斯抽采是降低煤层瓦斯含量，实现矿井瓦斯抽采达标最为经济、广泛、有效的技术手段。目前我国约有65%的煤矿顺层钻孔瓦斯抽采浓度较低，除钻孔本身塌孔、抽采管路连接不密实等原因外，另一原因是抽采钻孔封孔质量不佳，导致的抽采钻孔漏气引起。封孔材料是保障封孔质量的物质基础，常用的封孔材料存在粘度上升快，流动性差，凝固过快，强度低等缺陷；也存在不能渗入细小裂隙，与孔周缺乏很好的胶结性问题，同时部分材料在抵御温差变化引起的热胀冷缩方面也有局限，封堵效果不佳。亟需一种粘度低流动性好、放热温度低不发泡、凝固时间可控、抗压强度高的新型液态缓凝封孔材料。

本文研制了新型液态缓凝封孔材料，通过实验室测试了其凝固时间与抗压强度，理论分析了缓凝控制机制与材料对抗压强度的作用机理，最后建立凝固时间与抗压强度的关系式，研究成果如下：

（1）基于封孔材料聚合反应原理，分析材料凝固时间影响因素，改变异氰酸酯含量、聚醚多元醇种类及含量、催化剂种类及含量、增塑剂含量进行配方设计，制备封孔材料并测试凝固时间，结果表明当材料含量增加时，粘度增加，凝固时间缩短，其微观分子量、峰值温度及物理交联密度均增加。结合宏、微观分析得到材料的凝固时间的控制机制主要分为主体材料与助剂两方面，主体材料为异氰酸酯与聚醚多元醇种类与含量的变化，助剂主要为催化剂种类与含量、增塑剂含量的变化，异氰酸酯与含有羟基(-OH)的多元醇聚合生成氨基甲酸酯(-NHCOO)，此过程，具有较强配位作用的催化剂含有的电子，与主料、及其他助剂官能团间的孤对电子结合，形成空间轨道，提高配位能力，影响氨基甲酸酯(-NHCOO)形成的速度，分子量不断增加，阻碍分子链的定向排列，体系交联密度不断上升，凝固时间缩短。

（2）改变异氰酸酯含量、聚醚多元醇质量比、催化剂种类与含量、增塑剂含量设计配方，进行正交实验与单因素实验，分析材料影响因素的主次及单因素影响下材料抗压强度变化规律。未添加异氰酸酯，材料的抗压强度小于5MPa，随异氰酸酯含量增加，抗压强度增量大于10MPa，抗压强度超过30MPa；0~3范围内，聚醚质量比越大，材料抗压强度越大，大于4时，材料抗压强度反而减小；改变增塑剂含量，抗压强度整体较改变异氰酸酯含量、聚醚质量比低，相差5MPa左右，且增塑剂含量到一定程度还会出现减小趋势。随异氰酸酯、聚醚含量比、催化剂种类与含量、增塑剂含量增加，材料微观结构变化快，氢键强度高、结晶度高，抗压强度高。

（3）选取3组不同配比的材料，进行宏观凝固时间与抗压强度测试，随材料含量增加，凝固时间缩短，抗压强度增加，微观结构变化明显。引入粘结强度理论，建立凝固时间-抗压强度关系式，选取宏观所得参数，检验凝固时间-抗压强度关系式，并进行误差分析。对比实际测试结果，得误差分别为0.6、0.9、1.32，超出误差范围()，关系建立合理。

（4）采用3组不同配比的新型液态缓凝封孔材料，与2种矿方原有无机水泥基材料、有机聚氨酯材料作为对比，在下石节222工作面4^-2#煤层进行现场试验，跟踪监测为期35天的瓦斯抽采浓度与瓦斯流量，验证封孔材料优良性能，改进封孔材料。得到采用新型液态缓凝封孔材料封孔的钻孔，抽采流量高于采用水泥基与聚氨酯封孔的钻孔，第1、2、3号钻孔瓦斯流量较采用水泥基与聚氨酯封孔的D-1、D-2号钻孔瓦斯流量高30%。在抽采期内的瓦斯抽采浓度相对于水泥基与聚氨酯封孔材料的抽采浓度高，1、2、3号钻孔瓦斯浓度虽存在缓慢上升又下降趋势，但仍然比采用水泥基与聚氨酯封孔的D-1、D-2号钻孔瓦斯流量高20%。其中3号钻孔的抽采流量、瓦斯浓度整体上高于1、2号钻孔，证明随质量分数减小，封孔效果好。

The high gas content of coal seams seriously restricts the safe and efficient production of mines. Gas extraction is the most economical, widespread and effective technical means to reduce the gas content of coal seams and achieve the standard of gas extraction in mines. At present, about 65% of coal mines in China have low gas extraction concentration, except for the collapse of the drill hole itself and the poor connection of extraction pipeline, another reason is the poor sealing quality of the extraction drill hole, resulting in the leakage of gas from the extraction drill hole. The sealing material is the material basis to guarantee the quality of sealing. The commonly used sealing material has defects such as fast rise in viscosity, poor fluidity, too fast solidification and low strength; it also has the problems of not being able to penetrate into small fissures and lacking good cementation with the hole perimeter, while some materials have limitations in resisting thermal expansion and contraction caused by temperature changes, and the sealing effect is not good. There is an urgent need for a new liquid slow-setting sealing material with low viscosity, good fluidity, low exothermic temperature, no foaming, controllable solidification time and high compressive strength.

In this paper, we have developed a new liquid slow-setting sealing material, tested its solidification time and compressive strength through laboratory, theoretically analyzed the mechanism of slow-setting control and the mechanism of the material's effect on compressive strength, and finally established the relationship between solidification time and compressive strength, and the research results are as follows:

(1) Based on the polymerization reaction principle of sealing materials, factors influencing the solidification time of materials were analyzed, and the formula was designed by changing the content of isocyanate, the type and content of polyether polyols, the type and content of catalysts, and the content of plasticizer. The pore sealing materials were prepared and the solidification time was tested. The results showed that when the material content increased, the viscosity increased and the solidification time shortened. The microscopic molecular weight, peak temperature and physical crosslinking density increased. Based on macro and micro analysis, the control mechanism of the solidification time of materials is mainly divided into two aspects: the main material is the change of type and content of isocyanate and polyether polyols; the additive is the change of type and content of catalyst and plasticiser; the polymerization of isocyanate and polyols containing hydroxyl group (-OH) generates carbamate ester (-NHCOO). In this process, the electrons contained in the catalyst with strong coordination function, combine with the lone pair electrons between the main material and other auxiliary functional groups to form a space orbit, improve the coordination ability, affect the formation speed of carbamate (-NHCOO), the molecular weight is increasing, hinder the directional arrangement of molecular chains, the cross-linking density of the system is rising, and the solidification time is shortened.

(2) The formula was designed by changing the content of isocyanate, the mass ratio of polyether polyol, the type and content of catalyst, and the content of plasticizer, and orthogonal and single-factor experiments were conducted to analyze the main and minor factors affecting the material and the change of compressive strength of the material under the influence of single factor. Without adding isocyanate, the compressive strength of the material is less than 5MPa, with the increase of isocyanate content, the increment of compressive strength is more than 10MPa, and the compressive strength is more than 30MPa; in the range of 0~3, the greater the polyether mass ratio, the greater the compressive strength of the material, and when it is greater than 4, the compressive strength of the material decreases instead; changing the content of plasticizer, the overall compressive strength is lower than changing the content of isocyanate and polyether mass ratio. The difference is about 5MPa, and the plasticizer content will tend to decrease to a certain extent. With the increase of isocyanate and polyether content ratio, catalyst type and content, and plasticizer content, the microstructure of the material changes quickly, and the hydrogen bond strength and crystallinity are high, and the compressive strength is high.

(3) Three kinds of materials with different ratios were selected and tested for macroscopic solidification time and compressive strength. With the increase of material content, the solidification time was shortened, the compressive strength was increased and the microstructure change was obvious. The bond strength theory was introduced to establish the setting time-compressive strength relationship, and the macroscopic parameters obtained were selected to test the setting time-compressive strength relationship and to conduct error analysis. Comparing with the actual test results, the errors were 0.6, 0.9 and 1.32, which were beyond the error range (), and the relationship was established reasonably.

(4) Three groups of new liquid slow-setting sealing materials with different ratios were used, compared with two kinds of mine's original inorganic cement-based materials and organic polyurethane materials, and field tests were conducted in the 4^-2# coal seam of the lower stone section 222 working face to follow up and monitor the gas extraction concentration and gas flow for 35 days to verify the excellent performance of the sealing materials and improve the sealing materials. The extraction flow rate of the holes sealed with the new liquid slow-setting sealing material was higher than that of the holes sealed with cement-based and polyurethane, and the gas flow rate of holes 1, 2 and 3 was 30% higher than that of holes D-1 and D-2 sealed with cement-based and polyurethane. The gas extraction concentration during the extraction period was higher than that of the cement-based and polyurethane sealing materials. Although there was a slow upward and downward trend in the gas concentration of drill holes 1, 2 and 3, the gas flow rate was still 20% higher than that of drill holes D-1 and D-2 with cement-based and polyurethane sealing. The extraction flow rate and gas concentration of drill hole No. 3 are higher than those of drill holes No. 1 and 2, which proves that the sealing effect is good with decreasing mass fraction.