STUDY ON THE SEALING METHOD OF PIT SURGE WATER BASED ON NEW GROUTING MATERIAL

To address the low efficiency of conventional grouting methods in controlling sudden water inrush in deep excavations, this study developed a novel composite slurry. The base slurry consisted of cement-sodium silicate, modified with 1.5% polyacrylamide(PAM)and 1.0% sisal fiber(SH). A three-dimensional blocking and filtration system was constructed by integrating natural loofah skeletons(porosity ≈ 80%)with uniformly graded sand and gravel(1~7 mm, with equal proportions of each fraction). Laboratory tests demonstrated that the composite slurry increased retention by 44.83% compared to the original cement-sodium silicate slurry and maintained excellent sealing performance under flow velocities ranging from 0.2 to 0.6 m·s^-1. The three-dimensional network significantly reduced flow velocity, achieving a maximum reduction of 37.5%, and ensured over 80% soil retention even at 0.6 m·s^-1. These results indicate that the synergy between the modified slurry and the structural filtering system not only improves erosion resistance but also enhances consolidation and energy dissipation performance.