Granular piles are commonly used to improve bearing capacity and reduce settlements of soft soil in coastal and lowland areas. Due to various reasons, granular piles tend to acquire a non-uniform tapered-down cross-section in actual construction process. In this paper, a simple theoretical approach to predict deformation behaviour of soft ground reinforced with non-uniform granular pile–mat system is presented. A small-scale experimental set-up is fabricated in the laboratory and tests performed. Results predicted by the proposed approach compare well with the laboratory tests, and the field tests and other numerical test results available in literature. A parametric study has been carried out to evaluate the relative influence of granular mat thickness and relative stiffness on various responses of non-uniform granular piles.