Survey on the recent application of deep mixing method in road construction in Japan

To obtain basic data to promote the appropriate use of deep mixing method, survey on the recent application of deep mixing method was conducted using the data of soft ground countermeasure works for road construction in Japan over the last 10 years. The deep mixing method accounted for about half of all the countermeasures applied in projects where the depth of improvement or the thickness of the soft ground layer was 3 m or more. Column type improvement by wet mixing was the largest number of the cases among the deep mixing methods. Compared to the soft ground composed mainly of clayey and sandy soils, a trend toward higher binder amount was obtained for the improvement of the ground composed mainly of unusual soils.