Elastoplastic design theory for ultra-deep frozen wall considering large deformation features

The freezing method is a key sinking method used in deep aquifer. The frozen-wall design theory is a key technique for the freezing method. However, the previous design theories for a deep artificial frozen wall have neglected the influences of side-wall deformation on its sizes and locations. Thus, the associated designs tend to be unsafe and the earthwork excavations tend to be underestimated. In order to consider the influences of a large deformation, new solution formulas for excavation radius and outer radii before deformation occurs are deduced by finite strains, and a new design theory for frozen-wall thickness is established. The analytical results are compared with numerical ones by analyzing the effects of various parameters, such as the crustal stress, and the cohesion, internal friction angle, and elastic modulus of frozen soil, on the side-wall displacement and frozen-wall thickness. The results indicate that both the small deformation and large deformation problems can be solved by the new formulas, the theoretical formula neglecting elastic strains can be applied to large deformation with strain up to 0.15, and the new formulas can accurately calculate the amount of excavation earthwork, and provide a theoretical reference for the design of frozen wall in ultra-deep soil layers.