An experimental study of grouting in water-bearing ground based on the technology of gas driven water

If the water-bearing ground is modified by grouting, the pore water will have an adverse influence on the grouting effect under normal conditions. In order to improve the grouting effect, the technology of gas driven water is proposed to apply to the chemical grouting in water-bearing ground. The feasibility test of gas driven water is carried out in the saturated clay and silty sand. The results show that the gas can drive the pore water in the saturated silty sand, but not in the saturated clay. The reason for this is that the size of soil pore will directly affect the initial air-entry value Pc. What’s more, the air pressure should not exceed the limit stress Pmax, otherwise the split failure and large-scale air passage will occur within the soil. An imitative experimental device for the gas driven water and chemical grouting in the water-bearing ground is designed, and some contrast test are conducted in the saturated silty sand. The results show that the chemical grouting can improve more significantly the permeability, unconfined compression strength and microstructure of the saturated silty sand with the aid of air charging technique, and the SEM photographs also show the same consequence. In general, an air curtain will be generated in the water-bearing ground via air charging, which can provide a favorable environment for the grouting, setting and hardening of grout.