Development of mixed fine particles injection method as a liquefaction countermeasure

The purpose of this research is to develop a fine particle injection method to inject multiple solids with a small particle size into the ground with water in the sand ground where liquefaction is a concern. After injection, these materials react and solidify with the surrounding sand particles. From the materials that can be made into fine particles at low cost, combinations that are expected to have high strength after solidification were extracted. As a result, the combination of blast furnace slag, hemihydrate gypsum, and magnesium oxide fine particles satisfied sufficient compressive strength. In the ground injection, the higher the concentration of fine particles, the easier it is to clog, and it is necessary to inject a solution with a water powder ratio (weight) of about 6 to 10% at a high flow velocity. In the fine particle infiltration experiment using the two-dimensional model soil layer, the mixed fine particles were injected as a plan and solidified in a few weeks.