September 14, 2022
Application of High-Pressure Jet Grouting Technology in Soft Foundation Treatment
1. High-pressure rotary jet grouting treatment of soft foundation is suitable for soft and weak interlayers (clay, muddy soil, fine sand, etc.) in the stratum. The thickness of the interlayer is not large, and there is a certain buried depth. It is difficult to remove the soft and weak interlayers. Other construction methods (such as bored piles, hole digging piles, immersed tube piles, etc.) are difficult to construct and costly. This kind of stratum is conducive to high-pressure rotary jet grouting treatment, with low construction cost and good effect.
2. During the construction of high-pressure jet grouting piles, due to the replacement of some soil, there must be a certain amount of cement slurry returning to the ground with the soil. If the slurry returning to the ground can be recycled, it can not only reduce the construction cost but also reduce the workload of slurry discharge. However, it should be noted that the sand content of the slurry must be controlled during recovery to prevent damage to the grouting pump. At the same time, a certain amount of cement should be added to the recycled cement slurry to ensure the strength of the consolidated body.
3. High-pressure jet grouting according to different conditions of different formations to fill slurry, especially the formation containing sand, gravel layer leakage is serious, filling slurry should pay attention to make up to prevent slurry shrinkage or leakage, pile head to form holes, affecting the quality of the pile.
4. When drilling pilot holes, the depth should be 0.3m-0.5m more than the depth of the spray to ensure smooth pipe down to a predetermined depth. After the pilot hole is drilled, into the pipe before, be sure to cover the orifice, in order to avoid debris into the hole against the down nozzle.
5. In order to prevent the nozzle from being blocked during the downpipe process, it is best to take protective measures for the nozzle before the downpipe.
6. The end of the pile (contact surface with the bearing layer) should be rotated a few more laps before starting to lift the nozzle upward.
7. In the process of jet grouting, one or two directional jets are timely injected into each pile, which has a certain effect on improving the bearing capacity of the pile.
