A Study on Altering the Cross-Sectional Shape and Altering the Quality of the Jet Grout Column

After a big earthquake hit east Japan, there is an increasing number of projects to reinforce aseismatic structure of buildings. Jet grouting is one of the effective methods to cater to the increasing needs. However, there are few cases applying jet grouting to the foundations of buildings because jet grouting is more expensive and more difficult to control the quality than mechanically mixing methods. To reduce the cost of jet grouting, we invented a new technique to construct rectangular-like columns instead of circular columns and set them in a row. This technique reduces the total number of columns, the production time and the production cost. Some field tests were conducted to construct the new columns. We succeeded in constructing the new columns and confirmed that the qualities and the construction efficiencies of the rectangular-like columns are not less than existing columns.