A new calculation method for life cycle settlement of soft ground with creep treated by columns

Abstract

For soft soils, creep settlement plays an important role in the full life cycle performance of infrastructures, which is a serious concern for engineers and researchers. Columns such as deep cement mixed (DCM) soil columns are commonly adopted to treat soft grounds in order to reduce the life cycle settlement of the infrastructures. However, the creep behavior of soft grounds treated by DCM soil columns is often ignored, inducing underestimated total settlements or unexpected differential settlements. In this study, a new calculation method is developed for the life cycle settlement of column-improved soft grounds by considering the creep of soft soils and load transfer between the columns and the surrounding soils. A physical model test with double-layer soil improved by DCM soil columns is designed and performed to demonstrate the feasibility of the calculation method. It is found that the settlements calculated by the proposed method show good agreement with the measured data in the physical model. A parametric study is conducted, revealing that the calculated settlement of the double-layer soil improved by DCM columns can be largely influenced by the stress concentration ratio, the permeability of the DCM columns, and the area replacement ratio. Finally, the proposed method is applied to calculate the settlement in a real project.