Development of the influence zone during controlled modulus column installation

Controlled Modulus Columns (CMC) are a ground improvement technique in which grout-based columns are formed by displacing soil with a specially designed auger. Their fast-track and efficient installation process has made them increasingly popular compared with other methods. However, installation effects induced by the CMC have not been studied adequately. Numerical simulation of this problem poses challenges due to large soil deformations caused by auger penetration and rotation during installation. This paper investigates numerical methods for assessing the effects of CMC installation. Finite element approaches, including Coupled Eulerian–Lagrangian and Arbitrary Lagrangian–Eulerian, were employed to model large soil deformations. An advanced constitutive model, SANISAND, developed by Dafalias and Manzari (2004), was adopted to simulate the soil behaviour. Numerical simulations were performed for different column diameters following typical field applications. The results revealed consistent trends across modelling techniques, with larger column diameters and greater penetration depths producing higher stresses and pronounced soil densification. The results indicate that large deformation effects and soil densification are captured to varying extents depending on the numerical formulation adopted. This research highlights the critical influence of column geometry and modelling choice in capturing realistic soil behaviour, offering valuable insights for optimising CMC design and installation in practice.