裂隙溃砂通道化学注浆堵水固砂机理研究

With the large, long and deep development trend of underground engineering construction in China, water and sand inrush has become a bottleneck problem in underground engineering. Chemical grouting in the fracture has been indicated to be an effective technological means to control water and sand inrush. In contrast to dynamic water grouting, the flow of sand/water mixtures which contain high content of sand is the key factor influence the grout propagation and gelling in fracture. In this proposal, a 2D fracture grouting test platform will be developed, and high-speed photography technology and the measurement of water/sand phase would be applied to obtain the information of seepage, diffusion and solidify of grout in the fracture during the water and sand inrush. During this process, the permeation grouting zone and dominant diffusion path would be divided, and the diffusion model of dynamic water and sand flow will be established. Meanwhile, the factors which influent the effect of water cutoff and sand retained will be determined and the mechanism of gelling will be investigated. The research finding would be used to lay a solid scientific foundation for improving the grouting treatment of water and sand inrush.

随着我国地下工程建设的大、长、深的发展趋势，突水溃砂成为制约地下工程建设发展的瓶颈问题。针对这一问题，在生产实践中出现了以封堵突水溃砂通道为主的化学注浆防治技术。不同于动水注浆，在突水溃砂注浆治理过程中，含砂量较高的水砂混合流的运动是影响浆液扩散和运移的关键因素。本项目在建立可视化裂隙突水溃砂注浆试验平台的基础上，采用高速摄像、压力传感系统及水砂分相测量装置等试验手段，获取溃砂过程中化学浆液在裂隙通道中渗流、扩散、固化等信息，划分浆液渗流固化区域及优势扩散通道，建立反映化学浆液在裂隙溃砂通道堵水固砂机理的动态演化模型；同时阐明动水砂条件下浆液堵水固砂封堵机理，确定影响化学注浆堵水固砂效果的主控因素，为改善突水溃砂注浆工艺设计奠定科学基础。

针对煤矿突水溃砂灾害的发生，生产实践中出现了以封堵突水溃砂通道为主的注浆防治技术，因此非常有必要在已有的注浆理论和实践基础上，进一步对突水溃砂通道注浆封堵的相关理论进行研究。本项目以矿山突水溃砂灾害注浆治理的工程实践为背景，构建二维可视化裂隙通道突水溃砂注浆试验平台，开展了水砂混合物在溃砂通道的运移规律试验，并针对裂隙突水溃砂通道进行了注浆封堵试验，获取了水砂混合物在溃砂通道的运移规律，以及浆液在裂隙突水溃砂通道中渗流、扩散、固化的过程信息，阐明了动水砂条件下浆液堵水固砂机理。研究发现：（1）水砂混合物的在垮落带溃砂通道中的运移模式可划分为渗流型和驱动型，并提出计算突水溃砂量的公式。（2）浆液在裂隙溃砂通道运移过程中出现“水-浆-砂”分层的现象，提出了浆液的分层扩散机制，指出加速砂颗粒沉积是快速封堵突水溃砂通道的关键。（3）浆液在突水溃砂通道的扩散可以划分为固砂和堵水两个阶段，建立了浆液在裂隙溃砂通道堵水固砂的动态演变模型和扩散数学模型。本项目对浆液在动水砂环境下在岩体裂隙通道内的分层扩散规律、以及固砂堵水封堵机理2个科学问题有了深入的认识，为改善突水溃砂注浆工艺设计奠定科学基础。