soilstabilisation

Soil stabilisation is the deliberate alteration of soil properties to improve engineering performance. It aims to increase strength, stiffness, durability, and load-bearing capacity while reducing deformability, permeability, shrink-swell, and susceptibility to erosion. Stabilisation is used for subgrades and bases in roads, railways, and airfields, for slope and retaining-wall stabilization, and for containment systems. Techniques may be applied alone or in combination.

Common approaches include mechanical stabilization, chemical stabilization, and reinforcement through geosynthetics. Mechanical stabilization relies on compaction, grading, and blending with granular materials to achieve target density and modulus. Chemical stabilization uses binders such as lime for clays, cement for various soils, and pozzolanic additives (fly ash, silica fume) to raise strength and reduce plasticity. Geosynthetics provide reinforcement and drainage control.

Applications include road bases and airfield pavements, railway subgrades, embankments, slopes, retaining structures, and landfill liners. Surface stabilization improves bearing capacity and surface durability, while deeper stabilization creates cemented or lime-stabilised layers that resist higher loads. Selection depends on soil type, climate, loads, durability requirements, and cost.

Design and assessment typically involve laboratory tests such as Proctor compaction, Atterberg limits, unconfined compressive strength, and California bearing ratio, alongside field tests and performance monitoring. Mix design and quality control are important to achieve specified results, and long-term performance depends on drainage, moisture fluctuations, and environmental exposure.

Environmental and practical considerations include emissions from binders, potential leaching, heat of hydration, and compatibility with surrounding soils and groundwater. Stabilisation projects should include environmental impact assessment, durability considerations, maintenance planning, and lifecycle cost analysis to identify the most appropriate strategy for a given site.