Consolidation calculation of a foundation partially penetrated by concrete‐cored gravel (CCG) columns

Abstract

A concrete-cored gravel (CCG) column is composed of a precast concrete pile inserted at the center of sand or gravel materials. This technique has been experimentally adopted to support the soft soils in China. However, there has been limited investigation on the consolidation characteristics of a CCG column improved foundation under embankment loading. This study develops analytical solutions for the consolidation of a composite foundation partially penetrated by the CCG columns. The rigid pile's upward and downward piercing effects were considered to improve CCG column-soil equal strain relationship. The partially penetrated consolidation problem was addressed by assuming the seepages in the unpenetrated layers to be vertical or horizontal and vertical combined. A simplified approximate method was also provided, enabling the users to quickly evaluate the consolidation process of a foundation partially penetrated by the CCG columns. The proposed solution was applied to a case history of an antiflood embankment on soft soil with partially-penetrated CCG columns, and a good agreement was found between predictions and the field measurements.