Characteristics and Application Potentials of Ground Improvement with Semi-Rigid Inclusions Based on an Innovative Composite of Polymers and Gravel-Paper

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The study investigates a semi-rigid ground-improvement material made by bonding gravel grains with adjustable polymer resins. Unlike conventional flexible stone columns or rigid concrete columns, the composite can be tailored to ground conditions and project requirements, with compressive strength reaching about 12 MPa.<br /><br />Image segmentation is presented as a quality-control method for assessing polymer distribution and content in laboratory samples and site drill cores. Estimated polymer content differed from the specified amount by an average of just 6%. Rheological tests showed that temperature strongly affects installation: polymer 01 remains workable for about 65 minutes at 10°C, but only 35 minutes at 20°C. Under typical ground conditions, it develops initial strength after roughly 18 hours; final strength is reached after curing and is four to five times greater. Polymer bonding increases cohesion, while coating the gravel grains reduces their friction angle.<br /><br />The material’s strength behavior was well represented by the Hoek–Brown failure criterion. In a numerical case study of a building on weak clay, composite columns reduced predicted settlement from 0.9 m without improvement to 0.02 m—similar to concrete columns and substantially better than stone columns, which reduced settlement to 0.08 m. The composite columns functioned as vertical load-bearing supports, with behavior more flexible than concrete columns.<br /><br />The results indicate potential for targeted, reliable ground improvement, including in difficult ground conditions and below groundwater. Temperature and curing time must be considered during construction. Further research is examining durability, workability, water saturation, long-term performance, and detailed numerical modeling.

Keywords

ground improvement

polymer resin

gravel columns

semi-rigid composite

image segmentation

compressive strength

rheology

settlement reduction

Hoek-Brown criterion

weak clay