Performance analysis of geotextile-encased stone columns using a simplified analytical approach

Area of Science:

• Geotechnical Engineering
• Soil Mechanics
• Civil Engineering

Background:

• Traditional stone columns have limitations in soft soils due to insufficient lateral confinement.
• Geosynthetic-encased stone columns (GESCs) provide enhanced stability but require accurate analytical models for design.
• Complex interactions between column, encasement, and soil necessitate advanced predictive tools.

Purpose of the Study:

• To develop a simplified semi-analytical iterative solution for evaluating ground reinforced with GESCs.
• To provide a tool for efficient prediction and design of GESC systems.
• To analyze the performance of GESCs across various parameters and identify optimal design configurations.

Main Methods:

• Modeling the GESC system as a unit cell with rigid-plastic stone columns and linear-elastic geosynthetic encasement.
• Dividing the soil profile into horizontal slices to account for depth-dependent behavior.
• Validating the model against field tests and finite element analysis for settlements, stress distribution, and encasement expansion.

Main Results:

• The proposed semi-analytical solution accurately predicts settlements, stress distribution, and encasement radial expansion.
• The model demonstrates effectiveness for area replacement ratios from 0 to 0.35 and encasement stiffnesses from 0 to 5000 kN/m.
• Optimal encasement stiffness was found between 2000 and 3000 kN/m, with an optimum partial encasement length ratio of 0.45.

Conclusions:

• The developed model offers a reliable method for assessing GESC performance in soft soils.
• Key factors influencing settlement improvement and stress concentration include area replacement ratio, encasement stiffness, and soil stiffness.
• The study provides an analytical design chart and Python code for practical GESC design applications.