JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech IV GROUND IMPROVEMENT TECHNIQUES Previous Question Paper (September - 2020 - R16)

Ground modification is required when the native soil at a construction site is inadequate to support the intended structural loads or fails to meet performance criteria. The primary need arises from the presence of weak, compressible, expansive, or liquefiable soils that pose risks of excessive settlement, bearing capacity failure, or slope instability.

The main objectives of ground modification include:

• Increasing the shear strength of the soil to improve bearing capacity and slope stability.
• Reducing compressibility to minimize total and differential settlements.
• Decreasing permeability to control seepage and prevent piping or erosion.
• Mitigating liquefaction potential in saturated cohesionless soils during seismic events.
• Controlling volume changes in expansive soils to prevent structural cracking.

The differentiation between shallow and deep soil modification is based on the depth of influence and the treatment methodology employed.

Shallow modification is generally more cost-effective for small-scale projects where surface improvement is sufficient to meet serviceability requirements. In contrast, deep modification is a specialized engineering intervention necessary when the depth of the problematic soil layer is substantial, requiring the improvement of the soil matrix at depth to prevent deep-seated failure or long-term consolidation settlement.