Characteristics of the stress and deformation of geosynthetic-encased stone column composite ground based on large-scale model tests

Abstract

This paper studies the bearing mechanism of geosynthetic-encased stone column composite ground, using large-scale model tests and discussing the effects of geosynthetic encasements of different lengths and moduli on the bearing mechanism. Based on the model tests, the stress concentration ratio of the column, bearing capacity of composite ground, column deformation, axial and radial stresses of the columns, and failure modes of composite ground improved by different columns were analysed. The results show that fully-encased stone column composite ground has a higher bearing capacity, and fully-encased stone columns have a higher stress concentration ratio, smaller and more uniform radial deformation, and transfer over half of the load acting on the column top to the column tip. In addition, the failure mode of the fully-encased stone column composite ground is due to the column punching into the upper gravel mat, rather than excess bulging in the radial direction of the column. In general, the behaviour o...