Analysis and settlement evaluation of an end-bearing granular pile with non-linear deformation modulus

Abstract

Ground improvement with granular piles increases the load-carrying capacity, reduces the settlement of foundations built on the reinforced ground and is also a good alternative to concrete pile. Granular piles or stone columns are composed of granular material, such as crushed stone or coarse dense sand. An analytical approach based on the continuum approach is presented for the non-linear behaviour of the granular pile. The formulation for pile element displacement is done considering the non-homogeneity of the granular pile as it reflects the true behaviour and also accounts for the changes in the state of the granular pile due to installation, stiffening and improvement effects. The present study shows that the settlement influence factor for an end-bearing granular pile decreases with increase in the relative stiffness of the bearing stratum. The settlement influence factor decreases with increase in linear and non-linear non-homogeneity parameters for all values of relative length. For a shorter pile, the rate of decrease of the settlement influence factor is greater in comparison to that for a longer pile. Shear stress at the soil–granular pile interface reduces in the upper compressible portion of the granular pile and increases in the lower stiffer portion of the granular pile due to the non-homogeneity of an end-bearing granular pile.

An Analytical Study of Partially Strengthened Single End-Bearing Granular Pile Near the Top and Bottom

“…Szypcio [22] presented the problem of plastic yielding at the head of a single column head and soil in the surroundings. The settlement influence factor for an end-bearing granular pile decreases with an increase in the bearing stratum's relative stiffness, as concluded by Sharma and Gupta [23].…”

A Numerical Model for the Compressive Behavior of Granular Backfill Based on Experimental Data and Application in Surface Subsidence

“…In general, the deformation modulus has been analyzed and usually obtained by the existing theoretical methods and stress-strain curves. For example, Kiran et al [15] proposed a method to calculate the deformation modulus of a granular pile by an in-situ load test, and Sharma and Gupta [16] found that the granular pile has non-uniform settlement according to the non-linear deformation modulus. In the laboratory, the deformation modulus of granular materials is usually obtained by compression experiments.…”