A theoretical model for estimating the water-tightness of jet-grouted cut-off walls with geometric imperfections

Abstract

Jet-grouted columns are commonly used to form cut-off walls in various water-seal project applications. However, affected by geological conditions or other factors, the geometric shapes of jet-grouted columns often deviate from the design values, which affects the water-tightness of cut-off walls. The probability distributions of factors inducing geometric defects in the cut-off walls are analyzed first according to field testing to estimate the water-tightness of jet-grouted cut-off walls with geometric imperfections. Based on this, three-dimensional simulation models of jet-grouted cut-off walls considering geometric defects are established. A simplified theoretical soil seepage model with a cut-off wall is deduced based on Darcy's law. The geometrical parameters in the simulation model are related to the cut-off thickness in the simplified theoretical model according to the equal seepage flow, and a theoretical model of a jet-grouted cut-off wall considering defects is obtained. Finally, the theoretical model is verified by numerical simulation and field observation, and it is found that the theoretical model can get reliable calculation results. This theoretical model can provide a basis for the parametric design of jet-grouted columns and can also predict the degree of seepage flow before soil excavation.