Yang Minghao, Zhang Shuai, Wang Mingbin, Qin Junling, Fan Wenhan, Wu Yue
School of Hydraulic and Civil Engineering, Ludong University, Yantai 264025, China.
Shandong Key Laboratory of Civil Engineering Disaster Prevention and Mitigation, Shandong University of Science and Technology, Qingdao 266590, China.
Materials (Basel). 2025 Aug 11;18(16):3746. doi: 10.3390/ma18163746.
The increasing depth of coal mine construction has led to complex geological conditions involving high ground stress and elevated groundwater levels, presenting new challenges for water-sealing technologies in rock microfissure grouting. This study investigates ultrafine cement grouting in microfissures through systematic analysis of slurry properties and grouting simulations. Through systematic analysis of ultrafine cement grout performance across water-cement (W/C) ratios, this study establishes optimal injectable mix proportions. Through dedicated molds, sandstone-like microfissures with 0.2 mm apertures and controlled roughness (JRC = 0-2, 4-6, 10-12) were fabricated, and instrumented with fiber Bragg grating (FBG) sensors for real-time strain monitoring. Triaxial stress-permeation experiments under 6 and 7 MPa confining pressures quantify the coupled effects of fissure roughness, grouting pressure, and confining stress on volumetric flow rate and fissure deformation. Key findings include: (1) Slurry viscosity decreased monotonically with higher W/C ratios, while bleeding rate exhibited a proportional increase. At a W/C ratio = 1.6, the 2 h bleeding rate reached 7.8%, categorizing the slurry as unstable. (2) Experimental results demonstrate that increased surface roughness significantly enhances particle deposition-aggregation phenomena at grouting inlets, thereby reducing the success rate of grouting simulations. (3) The volumetric flow rate of ultrafine cement grout decreases with elevated roughness but increases proportionally with applied grouting pressure. (4) Under identical grouting pressure conditions, the relative variation in strain values among measurement points becomes more pronounced with increasing roughness of the specimen's microfissures. This research resolves critical challenges in material selection, injectability, and seepage-deformation mechanisms for microfissure grouting, establishing that the W/C ratio governs grout performance while surface roughness dictates grouting efficacy. These findings provide theoretical guidance for water-blocking grouting engineering in microfissures.
煤矿建设深度的增加导致地质条件复杂，出现高地应力和高地下水位，给岩石微裂隙注浆止水技术带来了新挑战。本研究通过对浆液性能的系统分析和注浆模拟，对微裂隙中的超细水泥注浆进行了研究。通过对不同水灰比（W/C）的超细水泥浆性能进行系统分析，本研究确定了最佳可注入混合比例。通过专用模具制作了孔径为0.2mm、粗糙度可控（JRC = 0 - 2、4 - 6、10 - 12）的类砂岩微裂隙，并安装了光纤布拉格光栅（FBG）传感器进行实时应变监测。在6MPa和7MPa围压下进行的三轴应力 - 渗透实验量化了裂隙粗糙度、注浆压力和围压对体积流量和裂隙变形的耦合作用。主要研究结果包括：（1）随着水灰比的增加，浆液粘度单调下降，而泌水率呈比例增加。当水灰比 = 1.6时，2小时泌水率达到7.8%，该浆液被归类为不稳定浆液。（2）实验结果表明，表面粗糙度的增加显著增强了注浆入口处的颗粒沉积 - 聚集现象，从而降低了注浆模拟的成功率。（3）超细水泥浆的体积流量随粗糙度的增加而降低，但与施加的注浆压力成比例增加。（4）在相同的注浆压力条件下，随着试件微裂隙粗糙度的增加，测量点之间应变值的相对变化变得更加明显。本研究解决了微裂隙注浆在材料选择、可注入性和渗流 - 变形机制方面的关键挑战，确定水灰比决定浆液性能，而表面粗糙度决定注浆效果。这些研究结果为微裂隙止水注浆工程提供了理论指导。
