Abstract: The Pukou Central Business District (CBD) is in the soft soil zone Yangtze River of alluvium zone. The soilcement mixing column is the major soil improvement method for the combined utility culverts. A doublecell culvert cross section was used in area underneath Linjiang Road. The soilcement mixing column had a diameter of 500 mm, spacing in the longitudinal direction was 1.5 meters and 1.2 meters in the transverse direction. The performance of the soil mixing columns with various column stiffness, spacing and column length were parametric studied through the threedimensional finite element analysis. The soil improvement design for the utility culverts was able to be optimized from these numerical investigations.

Key words: combined utility culverts, soft soils, soilcement mixing columns, design optimizations