Field Application of High-Strength Deep Mixing Method for Waste Water Pipeline in Soft Ground

Recently, the high-rise residential buildings are being constructed in soft ground along the coastal area. Several infrastructures such as road, bridge, drinking and waste water supply lines and necessary to meet the basic requirement by the residents at the apartment complex. In this paper, the field application of high-strength deep mixing method (HDCM) is presented for reconstruction of collapsed waste water supply line with the diameter of 1000 mm in soft ground. Soil samples were obtained for various laboratory tests which were used for the numerical analysis of settlement for foundation soil of waste water supply line. The excessive settlement of waste water supply line was occurred due to the disturbance of the soft soil layer under the pipeline during the pull-out of sheet pipe walls. When the HDCM was applied as a ground improvement method to reinforce the foundation soil for waste water supply pipeline, the bearing capacity was increased greatly and the settlements was occurred as 37.6 and 48.5 mm, respectively, which is much less than the allowable settlement of 100 mm.