This standard provides comprehensive guidelines for the investigation, analysis, and implementation of control measures for landslides in hill areas. It covers a wide range of corrective and preventive techniques including drainage, retaining structures, slope modification, and bio-engineering. It serves as a fundamental reference for engineers and geologists involved in infrastructure projects in mountainous and geologically unstable terrains.
Landslide Control - Guidelines
Quick Reference Values
Minimum Factor of Safety for permanent slopes (static)1.5
Minimum Factor of Safety for permanent slopes (seismic)1.1
Minimum Factor of Safety for temporary slopes1.2
Typical inclination of soil nails from horizontal10 to 20 degrees
Typical slope of surface drains> 1 in 200
Recommended crest width for check dams0.6 to 1.2 m
Key Formulas
FoS = Resisting Forces / Driving Forces — Fundamental principle of slope stability analysis.
F = [Σ (c'l + (W cosα - ul) tanφ')] / [Σ W sinα] — General formula for Factor of Safety using Method of Slices (simplified).
Practical Notes
Drainage (both surface and sub-surface) is often the single most effective and economical landslide control measure; its importance cannot be overstated.
The selection of a control measure is highly site-specific and requires a thorough geotechnical investigation. A combination of measures is often more effective than a single solution.
Bio-engineering methods are cost-effective for shallow, surficial slides but are not suitable for deep-seated failures.