What is the function of shear keys in the design of retaining walls?

Posted in Soil Engineering | Email This Post Email This Post |
Print Friendly

In determining the external stability of retaining walls, failure modes like bearing failure, sliding and overturning are normally considered in design. In considering the criterion of sliding, the sliding resistance of retaining walls is derived from the base friction between the wall base and the foundation soils. To increase the sliding resistance of retaining walls, other than providing a large self-weight or a large retained soil mass, shear keys are to be installed at the wall base. The principle of shear keys is as follows:

The main purpose of installation of shear keys is to increase the extra passive resistance developed by the height of shear keys. However, active pressure developed by shear keys also increases simultaneously. The
success of shear keys lies in the fact that the increase of passive pressure exceeds the increase in active pressure, resulting in a net improvement of sliding resistance.

On the other hand, friction between the wall base and the foundation soils is normally about a fraction of the angle of internal resistance (i.e. about 0.8p ) where p is the angle of internal friction of foundation soil. When a shear key is installed at the base of the retaining wall, the failure surface is changed from the wall base/soil horizontal plane to a plane within foundation soil. Therefore, the friction angle mobilized in this case is p instead of 0.8p in the previous case and the sliding resistance can be enhanced.

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.

More Entries :

Share Information

What is Civil Engineering

Journals Books And Softwares

Branches Of Civil Engineering

Civil Engineering Jobs

Follow Us On FB

Knowledge Center

Civil Engineering Universities/Events

Gallery - Civil Engineering Pictures

Civil Engineering Forum

civil engineering forum

Search


engineeringcivil.com awarded best online publication by CIDC 2013

Top Contributors

Yahoo Group - Civil Engineering Portal

Subscribe to EngineeringCivil.com


Powered by groups.yahoo.com

Recently Added

Civil Engineering Links

anglo.com

Follow Us On FB