Experiment on the silica sol imbibition of low-permeability rock mass: With silica sol particle sizes and rock permeability considered

Abstract

It’s a universal engineering problem to seal micro-cracks of low-permeability argillaceous rock mass by grouting in the fields of civil engineering and mining. This paper achieved the grouting sealing of low- permeability artificial rocks with the permeability of 0.1–40 mD by adopting silica sol imbibition grouting. The variation characteristics of particle size, viscosity, and contact angle of silica sol during solidification and the pore size distribution of low-permeability artificial rocks were measured, and spontaneous imbibition tests of the artificial rocks were carried out. Finally, combined with the imbibition theory, percolation theory, and fracture medium grouting principle, the silica sol imbibition mechanism of low-permeability rocks and soil was discussed. The results show that: (1) Silica sol can be injected into artificial rocks with the minimum permeability of 0.1 mD through spontaneous imbibition; (2) The particle size increase of silica sol leads to decreased wettability, affinity, and injectability in grouting materials; and (3) In the range of 0.1–40 mD, the grout absorption first increases and then decreases with increased permeability. The number of large pores and fractures in the rock mass is related to injectability, and the number of small and medium pores is related to the internal driving force of imbibition. This study provides a theoretical basis for silica sol grouting sealing of low-permeability argillaceous rocks and is, therefore, an important reference for application.