Lateral compression response of overlapping jet-grout columns with geometric imperfections in radius and position
Canadian geotechnical journal (Print)
Spatial variability in the radius of a jet-grout column is commonly encountered in practice. Although various prediction models for the column radius are available, they were generally used to predict a nominal radius. The radius variation within a column has been seldom considered. In this study, the intra-column radius variation was simulated as a lognormal stochastic process. This was done based on the existing prediction models where the column radius can be correlated with the undrained
... th the undrained shear strength of in-situ soils. A slab consisting of overlapping jet-grout columns was considered. The slab serves as an earth retaining stabilizing structure in a deep excavation. The effects of radius variation on the mass performance of the slab were examined with the finite-element method. In addition, the positioning errors in jet-grout columns were also investigated. Owing to the random nature of the radius variation, the Monte-Carlo simulations were performed to estimate the statistic characteristics of the mass performance of the slab. A strength reduction factor was introduced and tabulated to account for the effects of geometric imperfections in the column radius and the column position. With the strength reduction factor, practitioners could quantitatively evaluate the effects of these geometric imperfections in design considerations. Practical recommendations on the column length and column spacing were also proposed.