Optimised design of jet-grouted rafts subjected to nonuniform vertical loading: Fid-Bau Portal

Optimised design of jet-grouted rafts subjected to nonuniform vertical loading

Algin, Halil Murat

Abstract A parametric study based on three dimensional finite element (3D FE) simulations of jet-grouted rafts (JGRs) subjected to nonuniform vertical loading has been conducted to investigate the interactions of JGR elements that are raft, jet-grouted columns (JGCs), granular interlayer mat and subsoil. The presented initial 3D FE simulation of a single JGC which is geometrically approximated with the rotated sinusoidal functional representation accounting for the actual variation of JGC diameter with depth is validated performing the back-analysis of the developed 3D FE models with the well-known experimental results reported in the literature. The image processing technique allowing the 3D FE modelling of complex irregular geometries has been employed and the extension of simulation to the complete JGR system is accomplished. Considering the design strategies previously defined for JGR systems, Paper resolves how the independent variables of interlayer thickness, JGC spacing and length under the core and edge areas of raft affect the design responses of settlements, bending moments and vertical stresses. The multi objective optimization analysis has been performed using Response Surface Method (RSM) to achieve the most economical design solution that satisfies the presented design constraints for JGRs. The effects of design constraints on the optimised design are presented graphically. Paper concludes the coupling of design strategies defined separately for JGC and piled raft provides opportunity to achieve the optimised design of complete JGR systems using 3D FE simulation with the image processing technique and RSM.