Ground Improvement
Techniques that strengthen/stiffen weak ground to avoid deep foundations
Ground improvement is the deliberate modification of weak or compressible ground to increase bearing capacity, reduce settlement, control liquefaction or accelerate consolidation — often a cheaper alternative to deep foundations or soil replacement. The technique is matched to soil type and target: stone columns/vibro for soft clays and loose sands (IS 15284 Part 1), grouting and lime/cement piles for various soils (IS 15284 Part 2), dynamic compaction and vibro-compaction for loose granular fills, and preloading with prefabricated vertical drains (PVDs) to speed consolidation of soft clays.
It is now standard on reclaimed land, soft coastal/alluvial deposits and liquefiable sites, with design and acceptance based on target post-treatment parameters (allowable bearing pressure, settlement, degree of improvement) verified by post-treatment field tests — plate/pile load tests, CPT/SPT, settlement monitoring. Selection balances cost, programme, vibration/noise constraints and the reliability of verification, and is increasingly used to enable shallow rafts where piling would otherwise be required.
- Reclaimed land + soft coastal/alluvial deposits
- Settlement + bearing-capacity improvement under rafts
- Liquefaction mitigation at seismic sites
- Accelerating soft-clay consolidation (preload + PVD)
- Avoiding/limiting deep piling on weak ground