Experimental investigation on grout propagation in poured aggregates for controlling water inrush in tunnels with flowing water

Abstract Background In recent years, the technology of blocking and grouting has been widely used in treatment groundwater inrush tunnels China’s mines. Studies have carried out on aggregates pouring under hydrodynamic conditions; however, there is lack studies grout propagation aggregate mass, which formed earlier stage. This paper presents an experimental investigation poured with flowing water, focused second stage, i.e., after first stage salvage inundated underground tunnel. Results this work, a visualized tunnel replica water was adopted to investigate main effects sealing efficiency, pressure variation, mechanism during different grain sizes conditions. A series experiments orthogonal array design were out, cement/sodium silicate change characteristics fluid obtained. The results show that efficiency descending order ratio, relative density aggregates, particle size distribution final difference both ends segment. cementation form grouted four types; T shape, H O shape shell shape. mode includes three permeation filling mode, compaction- compaction-fracturing reflects influence size, pressure. variation can be divided into categories; overall ascending type, step concave convex type. curve type mainly depends pressure, flowrate, gel time, grout. Conclusion flow rate decreased by approximately 60% 86% compared before grouting, bulk hydraulic conductivity more than 80%, reflecting great improvement research graded mass guiding significance for construction rapid disaster inrush.