【作者】 张超；

【导师】 周延； 林柏泉；

【作者基本信息】 中国矿业大学 ， 安全技术及工程， 2014， 博士

【摘要】 钻孔抽采是煤矿瓦斯治理的基础技术手段之一，应用范围广泛。而高瓦斯松软煤层由于在煤化过程中受到地质构造的破坏，普遍煤质松软，加上瓦斯压力的作用，在施工抽采钻孔后，封孔段易产生失稳、变形，致使钻孔难以密封，无法保证瓦斯抽采效果。除了封孔段的稳定性，封孔质量是影响瓦斯抽采浓度、孔口负压、甚至整个钻场抽采效果的又一重要因素。因此，开展高瓦斯松软煤层封孔段易失稳钻孔的动态密封技术研究，对提高钻孔抽采效率，遏制瓦斯突出、瓦斯爆炸等重大事故的发生，具有十分重要的现实意义。本文首先分析了高瓦斯松软煤层瓦斯抽采钻孔封孔段失稳的特征及原因，并在此基础上探讨了封孔段失稳对钻孔周围裂隙的影响以及对封孔质量的影响。结合理论分析，认为需要新的密封工艺、新的密封材料以满足高瓦斯松软煤层封孔段易失稳钻孔密封的需要，进而实现瓦斯高效抽采。其次，通过对注浆加固钻孔封孔段作用机理进行研究，认为采用煤岩体注浆技术可以把某些可凝浆液注入到煤岩体的裂隙或孔隙中，使煤岩体形成强度高、抗渗性好、稳定性高的新结构体，从而改善煤岩体的物理力学性能，提高煤岩体稳定性。通过钻屑法现场实测，确定出试验区所在埋深的煤层合理封孔深度为14m。利用钻孔窥视仪对现场钻孔进行观测，直观确定了钻孔内部的情况，并结合钻屑量随钻孔深度变化规律，将钻孔封孔段划分为破裂膨胀发展区、破裂膨胀稳定区、破裂膨胀剧烈区、破裂膨胀趋缓区、破裂膨胀消失区。再次，针对高瓦斯松软煤层封孔段易失稳且钻孔密封难的问题，基于主动式密封“固封液，液封气”的原理，发明了加固封孔段和动态密封一体化的新型密封技术及方法。根据钻孔封孔段加固机理以及现场应用对加固材料的性能要求，通过添加膨胀剂、减水剂等材料，研制出了一种水泥基固化钻孔材料。利用FEIQuantaTM250环境扫描电子显微镜、低场核磁共振等设备，对新研制的水泥基固化钻孔材料的特性进行了研究，为现场施工提供了理论指导。基于动态密封的技术原理以及现场应用对该技术配套材料的特殊要求，研制出初始流动性大、可泵性好、凝固时间可调、长时间保持膏状，且有一定粘聚力的粘液密封材料。在广义达西定律和球形、柱形扩散理论模型的基础上，推导出了幂律型浆液在钻孔中进行渗透注浆的扩散公式。通过数值模拟的方法，对注入浆液在钻孔周围的分布进行数值模拟和分析，并根据模拟结果对封孔段各部分的注浆长度进行了优化。最后，为考察加固式动态密封的实际应用效果，在潞安集团常村煤矿53采区进行了现场工业性试验，并对相关瓦斯抽采参数进行了测试、分析。通过以上研究，在理论上阐明了加固式动态密封技术原理，在方法上提出了适用于高瓦斯松软煤层易失稳瓦斯抽采钻孔的加固式动态密封新技术，在材料上研制了配套的水泥基固化材料和膏体状粘液密封材料。上述技术、材料在现场试验应用中取得了良好效果，表现出了显著的技术优越性。课题研究期间，作者公开发表学术论文10篇，其中EI检索5篇，取得或申请受理专利9项，其中发明专利4项，获得省部级科技进步一等奖2项，排名第十。更多还原

【Abstract】 Borehole extraction is widely used to control mash gas in coal mine. In somecases, coal seam destroyed by geological processes so that the physical property ofcoal is instability. If the gas pressure of coal seam is large enough, the coal seam canbe called high gassy and soft coal seam. The boreholes in these coal seam are easy toproduce distortion. It’s hard to seal borehole and pose a great difficult to dischargemash gas from the high gassy and soft coal seam. On the basis of the stability ofboreholes, the effect of sealing has an impact on the gas concentration and negativepressure, and even the effect of drainage in the whole boreholes field. Therefore,performing the research relating to dynamic sealing techniques for boreholes witheasy-failure sealing segment is one of important practical significance to improve theefficiency of drainage and reduce the number of boreholes, and to prevent and controloutburst of gas and explosion.This paper firstly analyzed the characters of failure for boreholes in high gassyand soft coal seam, and studied the reasons for it. Then it was got that the efficiencyof sealing was influenced since the failure of sealing segment resulted to thedevelopment of fractures around the boreholes. Theoretical analysis suggested thenovel sealing techniques and materials could meet the need from borehole sealing andrealizing the high-efficiency drainage.Secondly, this paper studied the mechanism of grouting reinforcement for sealingsegment and the law of flowing for seriflux, which suggested that the groutingtechniques could inject the seriflux into the fractures existing in coal and rocks andmade the coal and rocks form novel structures with high intention and stability,and improving the properties and stability of coal and rock. A reasonable depth forsealing was determined to14m finally for coal seam in test field. Internal conditionsof boreholes were got through the infrared borehole imaging tool. According to thelaw between the amount of cuttings and depth of boreholes, sealing segment wasdivided into fractures and inflation developing area, fractures and inflation stable area,fractures and inflation severe area, fractures and inflations decreasing area and nonefractures and inflation area.Thirdly, in allusion to the problem in sealing for easy-failure boreholes in highgassy and soft coal seam, this paper came up with a novel approach for sealing byreinforcing dynamic sealing techniques. Based on the“solid seal liquid, liquid sealgas” Mechanism and the requirements of matched materials, cement solidification drilling materials was developed by adding swelling agent and water reducing agent.Incorporation and infiltrate in borehole walls for polyurethane material and curedmaterial were compared through environmental scanning electron microscope FEIQuantaTM250. According to the mechanism of reinforcing dynamic sealingtechniques and the requirements of matched materials, seriflux with certain cohesionwas got, which could meet the need of reinforcing dynamic sealing techniques. On thebasis of generalized Darcy’s law, spherical and cylindrical theoretical model fordiffusion, mechanism of diffusion for power law was got. The distribution of serifluxinjected in coal and rock was simulated through FLUENT, which optimized the lengthof every stage.Finally, in order to evaluate the effect of reinforcing dynamic sealing techniques,field tests were performed in NO.53panel of Chang Cun coal mine belonging to LuAn Company, as well as tests and analysis of relating parameters for gas drainage.Through above research, this paper theoretically expounded the mechanism ofreinforcing dynamic sealing techniques, then developed novel techniques of dynamicsealing with pressure which is appropriate to nearly horizontal boreholes in high gassyand soft coal seam and matched materials. In terms of equipment, pneumatic thickseriflux grouting pump and matched pneumatic mixer. Field applications indicted thesystem has great advantages comparing with traditional materials and techniques.During the research, the authors published10papers, in which five has been indexedby EI, obtain or apply for the processing of9patents,4of which are invention patents,and won the first award for Scientific Advencement of provincial, ranking tenth.更多还原