RCC-Design.github.io

DESIGN OF RETAINING WALL

1. Introduction

Structural elements that restrain soil to maintain elevation differences. Provide lateral support where ground level changes are needed.

Primary Functions:

• Prevent erosion/slope failure
• Create level ground on slopes
• Support infrastructure
• Manage drainage
• Landscaping

2. Wall Types

Type	Mechanism	Typical Height	Key Features
Gravity	Own weight resists pressure	<3m	Stone, concrete, gabions
Cantilever	Reinforced concrete shape	3-6m	Stem & base slab
Sheet Pile	Thin driven sections	Variable	Steel/vinyl, temporary/waterfront
Anchored	Cables anchored behind	High walls	For difficult conditions

3. Applications

• Civil: Highway embankments, bridge abutments, basements
• Geotechnical: Slope stabilization, erosion control
• Landscape: Terrace gardens, noise barriers, aesthetics

4. Key Pressures

Earth Pressures:

• Active (Pa): Wall moves from soil = ½γH²Ka
• Passive (Pp): Wall moves into soil = ½γH²Kp
• At-Rest (P₀): No movement = ½γH²K₀

Additional Loads:

• Hydrostatic: Groundwater pressure
• Surcharge: Adjacent structures/traffic
• Seismic: Earthquake forces

5. Design Essentials

Stability Checks:

1. Overturning: Resisting/Overturning moment ≥ 1.5
2. Sliding: Resisting/Driving force ≥ 1.5
3. Bearing: Soil pressure ≤ Allowable capacity
4. Overall: Deep-seated failure check

Drainage: Weep holes, drainage pipes, free-draining backfill

Materials: Concrete (most common), masonry, steel, timber, geosynthetics

DESIGN STEPS

Cantilever Retaining Wall