BEST guide on Reinforced Earth Wall-Types,Uses

What is"Reinforced Earth Wall"-Types, Uses

Reinforced earth wall is a type of Retaining wall which is used for preventing the backfill soil from sliding and erosion. There are mainly four types of retaining wall. Get the complete guide on reinforced earth wall.

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What is the Reinforced Earth wall?

Definition: The Reinforced earth wall is a composite material which is usually used to retain earth (soil) and prevents soil mass from eroding and sliding away.

The main purpose of having Retaining earth wall is to prevent soil from sliding and resist the pressure of the earth which it is holding back.

When there is intended change in ground elevation, we provide retaining wall to support to the earth from sliding.

Before moving into the classification of Reinforced earth wall, let's learn about why we need to provide Reinforcement.

Here are some requirements of reinforcement:

• To enhance the Stability and the strength to resist lateral pressure.
• To increase the service life of the retaining wall.
• To make the most economical design

Types of the reinforced earth wall

Evolution of 'Reinforced earth retaining wall' gives us various options for choosing the right one for our need.

Here are some most important types of Reinforced earth Retaining wall(RE RW)

YOU MIGHT LIKE: TYPES OF FOUNDATION AND THEIR USES

1. Gravity retaining walls
2. Buttressed and counterfort wall
3. Mechanically stabilized earth(MSE) with geosynthetic or metal reinforcement
4. Segmental retaining wall.

Others are sheet pile, anchored wall etc.

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➤ GRAVITY RETAINING WALL

This is one of the oldest types of retaining wall which is still in popularity.

Here the huge amount of self-weight of retaining wall resists the lateral pressure caused by retained soil.

We know that the amount of force required to move a lightweight object is higher when compared to heavyweight object.

Similarly, gravity wall made of masonry or concrete or even stone rely on the weight of their own mass and is able to resist the lateral pressure occurred by retained soil. 

These types of retaining wall are thicker than other retaining walls. Usually, the thickness varies from 50-60% of the height of the wall.

Up to 3-meter, gravity wall is most suitable.

➤BUTTRESSED AND COUNTERFORT WALL

First and foremost thing is that there is a thin line between buttressed and counterfort wall.

Both of them are the type of cantilever retaining wall. A triangular and vertical shaped beam is used for both buttressed and counterfort to enhance the load resisting capacity.

Main Difference b/w Buttressed and Counterfort-

SOURCE:SOILMANAGEMENT.COM

• For buttressed, triangular beams are located on the front side of retaining wall. 
• But in the case of, counterfort beams are placed on the backfill side.

In both cases, the structural action remains the same. When the height is more than 7 meter, the vertical bracing system(beams) is provided.

**This type of retaining walls consists of heel slab, toe slab, stem, and buttressed/counterfort.

Where heel slabs and toe slab acts as a continuous slab.

➤MECHANICALLY STABILIZED EARTH(MSE)

MSE

It is a type of retaining wall consists of compacted earth layer(backfill)and soil reinforcement elements.

The stability of the wall is derived from the friction and tension force between the backfill soil and reinforcement element.

The primary function of MSE is protecting the backfill soil from erosion.

Soil reinforcement elements that are used in MSE can be made of steel or geosynthetic in the form of grid, ladder or even strips.

Here I mentioned some advantages of using MSE to retain earth:

1. Extreme height of retaining wall can be achieved to retain earth.
2. It can resist the high amount of lateral pressure as the total pressure is distributed over a wide area.
3. Resistance to seismic forces.
4. Alignment of the wall is superior.

➤SEGMENTED RETAINING WALL

SOURCE:NPTEL

A segmented retaining wall is also known as the modular retaining wall which is consists of concrete blocks or segment that interlock with each other.

This also consists of lateral geogrid tieback system. In this system, lateral geogrid tiebacks are placed in the backfill area and this geogrid also helps to stabilize the backfill soil.

Benefits of using a segmented retaining wall:

• Rapid construction.
• Concrete footing is not necessary.
• Because of additional support to the wall, higher and steeper retaining wall can be constructed.

➥ Factors that should be considered while the designing of reinforced soil wall:

1. Two major types of stability must be investigated- a. internal stability, b. external stability.
2. Types of soil to be retained.
3. local equilibrium
4. Total tensile strength
5. Bearing capacity of subsoil
6. Base sliding.
7. overturning failure

Trending: Geosynthetic Reinforced Soil Walls 

This types of wall are increasingly becoming popular. The traditional Gravity retaining walls are much expensive to construct.

Thus reinforcement is introduced to make stronger and economical wall.

As the main material of reinforcement Metal strip is the primary choice.

But using metal strip won't give you the ideal type of wall.

Yes, there are many cons of using metal as the reinforcement which is listed below:

• High cost
• Can't be adopted with many indigenous materials.
• High sensitive towards corrosion.

GEOSYNTHETIC

But geosynthetic as a reinforcement in soil is gaining more popularity day by day due to its benefits.

Advantages of geosynthetic material:

• Economical
• can be used with many indigenous materials.
• Durability is high.
• The drainage system is superior.
• Easy handling.
• high in flexibility.

Due to its high flexibility, it can tolerate more earthquake load and high settlement.

Conclusion

Here you have learned the basic concept behind Reinforced earth wall, Types of retaining wall and their uses.

During the design of any retaining wall, you must consider the passive earth pressure.

[ passive earth pressure is the pressure developed by the backfill soil ]

The overall stability of retaining or reinforced wall follow some parameter:

• soil unit weight.
• water table location.
• internal friction of earth.

Backfill drainage system should be followed strictly. The drainage system is very important and underestimated by engineers.

This can cause saturation of backfill soil which may harm the stability of wall.

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