developing in-situ permeability and air voids requirements for open-graded friction course pavement: case study

Floating deep mixed column is an effective ground improvement method to treat soft soils. however, the traditional settlement estimation formula under the assumption of equal strain is not consistent with the actual situation. to investigate the settlement behavior of floating columns, a series of laboratory model tests and finite element analyses were carried out. the results reveal that the degree of consolidation of ground improved by floating columns is 10–20% lower than that of end-bearing columns, and the column–soil ratio of floating column treated ground is between 4 and 8. the settlement of improved layer calculated by equal strain assumption is lower than the measured settlement and the error between them is affected by load intensity, depth improvement ratio, and column–soil modulus ratio of floating columns. a simplified method for the settlement calculation of ground improved by floating columns has been proposed considering influence coefficients. the validity of the method was verified by the cases in the literature. © 2021, iran university of science and technology.