BeginnerTopic 37 of 112Civil & Structural
Retaining walls
Hold back soil; designed against overturning, sliding and bearing failure.
In depth
Gravity, cantilever, counterfort, sheet pile, MSE and anchored walls retain soil. Design checks: overturning (FS≥2), sliding (FS≥1.5), bearing and global stability. Drainage behind the wall prevents hydrostatic pressure build-up; weep holes and filters are essential.
Key points
- Active and passive pressures
- Backfill selection
- Reinforced soil with geogrids
ExampleA highway embankment uses geogrid-reinforced MSE walls.
Retaining walls hold back soil and must resist overturning, sliding and bearing failure, so their design is a core geotechnical task.
What is Retaining walls?
Hold back soil; designed against overturning, sliding and bearing failure.
Why is it important to understand retaining walls?
Retaining walls hold back soil and must resist overturning, sliding and bearing failure, so their design is a core geotechnical task.
What are the three main checks for a retaining wall?
Overturning about the toe, sliding along the base, and bearing failure of the soil below the base.
Why does drainage matter behind a wall?
Water build-up increases lateral pressure significantly, so drainage is a key design element to reduce the load.
How is Retaining walls used in practice?
Typical applications include designing a wall to hold back a garden terrace, checking a basement wall against lateral earth pressure and building a wall to support a road cut through a hillside.
What should I learn before Retaining walls?
Study "Deep foundations" first (topic 36 of 112 in Civil & Structural). It covers the groundwork this topic builds on.
What are the key points of Retaining walls?
Active and passive pressures. Backfill selection. Reinforced soil with geogrids.
Can you give an example of Retaining walls?
A highway embankment uses geogrid-reinforced MSE walls.
What comes after Retaining walls?
The next topic is "Earth pressure theories", which builds directly on this one.
How difficult is Retaining walls?
It is classed as Beginner in Civil & Structural (topic 37 of 112). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.