6-Mechanically Stabilised Earth System

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APPLICATION OF GEOTECHNICAL ENGINEERINGGEOTECHNICAL ENGINEERING

CE451A Dr. Rajesh Sathiyamoorthy, IIT Kanpur

MECHANICALLY STABILISED EARTH SYSTEMS


Overview of Retaining Walls categories

Externally stabilized

Internally stabilized

In-situ walls (cut walls)

Gravity walls (fill walls)

Mechanically stabilized (fill wall)

In-situ Reinforced (cut wall)



The classification of retaining wall systems is based on the basic geotechnical mechanism used to resist lateral loads and the construction method used for the installation of the wall. The following are definitions used to classify retaining wall systems:

Externally Stabilized Structures: Externally stabilized structures rely on the integrity of wall elements (with or without braces, struts, walers and/or tiebacks or anchors) to both resist lateral loads and also prevent raveling or


tiebacks or anchors) to both resist lateral loads and also prevent raveling or erosion of the retained soil.

Internally Stabilized Structures: Internally stabilized structures rely on friction developed between closely‐spaced reinforcing elements and the backfill to resist lateral soil pressure. A separate, non‐structural element (facing, erosion control mat and/or vegetation) is attached to prevent raveling or erosion of the retained soil.

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Internally stabilized Externally stabilized


Soil particle at interface with back of structural facing


Based on how they are constructed◦ Cut Walls: Wall is constructed “top-down”.



Based on how they are constructed◦ Fill Walls: Wall is constructed “bottom - up”.


Classification of Retaining wall systems


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Cost comparison of RE walls


Classification of Reinforced Soil Retaining Walls

Face units are the structural support.

Reinforcement added to a “wall system” to increase achievable wall heights.

Reinforcement is the structural support.Face panels alone could not be a “wall system”.

Wall System Internally stabilized Wall System Internally stabilized Earth System


Components of Reinforced Soil Retaining Walls


Typical Highway supported by Reinforced soil wall


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Different types of wall configurations


Different types of wall configurations


Types of wall facing in Reinforced Soil Walls

Full height panel wall

Segmental panel wall

Modular block faced wall

Geotextile wrapped


ppretaining wall

Types of reinforcement in Reinforced Soil Walls

Geosynthetic Reinforcement• Geotextiles• Geogrids• Polymeric strips• Grids made of strips


Steel Reinforcement• Steel strips• Welded steel meshes• Steel strips with anchors• Twisted steel wire mesh

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Construction sequence of RE walls








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Different types of RE walls built in India


Failure of RE walls


Failure of RE walls


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Failure of RE walls


Failure of RE walls


Failure of RE walls


Different types of RE walls built in India


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Failure of RE walls


Failure of RE walls


Failure of RE walls


Failure of RE walls


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Failure of RE walls


Failure of RE walls


Failure of RE walls


Failure of RE walls


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Failure of RE walls


Failure of RE walls


Failure of RE walls


Failure of RE walls


Documents

6-Mechanically Stabilised Earth System