地应力约束下超细硫铝酸盐水泥基注浆材料的基础研究

Section coal roadway is an urgent need for grouting technology to ensure efficient exploitation of the mine safety, and the key of grouting technology lies in the performance of the grouting materials. Existing grouting materials can not fully meet the requirements of coal seam for material fineness, stability, and fluidity, setting time, invasive, early strength and long-term stability of the consolidation coal. In preliminary studies applicants develop an ultrafine sulfoaluminate cement-based grouting materials, which are proved well through the field. The project is planned on the basis of the existing work, to carry out the basic research of ultrafine sulfoaluminate cement-based grouting materials under the ground stress. Under the condition of high water-cement ratio the hydration kinetics of ultrafine sulfoaluminate cement-based grouting materials is studied to establish hydration kinetics model. Under the stress the structure and properties of the hardened paste is studied to control structure and properties. The interface zone structure of consolidation of hardened paste and coal is studied to establish the interface zone structure model of consolidation. Under the stress mechanical properties and permeability of consolidation of hardened paste and coal is studied. Under stress the relationship of the crack propagation, deformation performance and permeability of consolidation of hardened paste and coal is studied. The purposes of the research is reveal and control the rule of structural formation of consolidation of hardened paste and coal under the ground stress, and maintain long-term stability of coal seam.

大断面全煤巷道迫切需要注浆技术以保证矿井安全高效开采，而注浆技术的关键在于注浆材料的性能。现有的注浆材料不能完全满足煤层巷道对材料细度、稳定性、流动性、凝结时间、浸润性、早期强度及固结煤后长期稳定性的要求。申请者在前期研究中开发出了一种超细硫铝酸盐水泥基注浆材料，通过现场应用效果良好。本项目拟在已有的工作基础上，进行地应力约束下超细硫铝酸盐水泥基注浆材料的基础研究。研究大水灰比条件下超细硫铝酸盐水泥基注浆材料的水化动力学，建立其水化动力学模型；研究地应力约束下硬化浆体的结构与性能，提出结构与性能调控的措施；研究硬化浆体固结煤的界面结构，建立固结煤的界面结构模型；研究应力作用下注浆固结体的力学性能及渗透性，探明固结体在应力作用下的裂缝扩展、变形性能与渗透性之间的关系。研究工作能探明地应力作用下煤层巷道注浆固结体的结构形成与调控，使煤层巷道保持长期稳定。

本课题以超细硫铝酸盐水泥基注浆材料为研究对象，重点从水化动力学、结石体的微结构与性能、结石体-煤岩界面区结构与性能、结石体稳定性、注浆材料用纳米增强剂及减水剂等方面进行了系统研究。研究了材料粒径、水灰比、石膏及石灰掺量等因素对水化产物组成、液相离子浓度、水化放热速率等的影响规律，阐明了注浆材料水化动力学特征；通过运用宏观性能测试与微观分析相结合的方法，建立了结石体力学性能和体积膨胀性能与结石体微结构特征（水化产物形貌、产物相组成、晶体与胶体比例含量等）之间的关系；探明了注浆结石体-煤岩界面区特征，注浆材料与煤岩间界面张力大，浆液难以在煤岩表面铺展，导致注浆结石体-煤岩界面处表现出高孔隙率特征，结合状况差；结石体-煤岩界面存在铝胶和钙矾石晶体富集状况；通过运用界面张力理论，建立了结石体-煤岩界面过渡区的物理模型和界面过渡区厚度数学计算模型；在界面理论指导下，提出了改善结石体-煤岩界面结合状况的方法。阐明了环境湿度、外加剂对结石体的体积稳定性影响规律；开发出了与单硫型水化硫铝酸钙具有同晶结构的锂铝类水滑石纳米增强剂，锂铝类水滑石对注浆材料的增强机理是由于晶核作用提高了浆体的水化速率，增加了水化产物的生成量，改善了浆体的微观结构，提高了力学、凝结及稳定性能。发现带有苯环基团的聚羧酸减水剂对硫铝酸盐水泥基注浆材料有较好的减水作用，合成的PCE-LG聚羧酸减水剂由于苯环基团的位阻作用减少了在钠基膨润土中的吸附量，从而提高了减水作用。项目研究成果将能够为煤矿用超细硫铝酸盐水泥基注浆材料的开发设计提供基础理论支撑。