Experimental study of anti-washout property and gelling performance of fast-gelling grout

Grouting technique is widely used to control the water inrush hazards and increase the strength in tunneling and underground engineering. Therefore, the anti-washout property of grout under the flowing water condition is the key factor that determines the grouting effect. In order to evaluate the anti-washout property and the gelling performance of the fast-gelling grout, a specific test apparatus was designed to simulate the vital process of the grout being flushed by the flowing water before gelled. With this device, a series tests were carried out by controlling the velocity of water flow and the mixing proportion of grout. The grout retention ratio(GRR) index was proposed to evaluate the anti-washout property quantitatively. The test results showed that the grout of cement-sodium silicate achieved a large grout retention ratio when the water flow velocity was small, however, the grout retention ratio decreased significantly with the increasing of the velocity of water flow. The GRR of the grout of cement-sodium silicate was influenced by the mass ratio of water to cement and the volume ratio of cement to sodium silicate of the grout. The modified polyurethane grout had a larger GRR under the fast water flow condition and the gel was more compact, which meant that the modified polyurethane grout had the better anti-washout property and the gelling performance. According to the different anti-washout property and gelling performance of grout, a method of choosing grout materials reasonably to dealing with the water inrush was proposed. ©, 2015, Academia Sinica. All right reserved.