Shear Key effectiveness

[mann]

I am wanting to get some opinions on the use of shear keys to increase sliding resistance of retaining walls.&nbsp;&nbsp;<br><br>Does anyone have an opinion on shear key effectiveness.

 

[Ginger]

i believe shear keys to be an effective method of preventing sliding.&nbsp;&nbsp;However, their efficacy is dependant upon the degree of workmanship one uses in forming the key.&nbsp;&nbsp;It is essential that the minimum of disturbance is created to the passive face in front of the key during the excavation process.&nbsp;&nbsp;If necessary, use sheet piles to ensure a good clean working face with no ground softening.&nbsp;&nbsp;This will ensure that the soil can generate the required passive resistance.<br><br>One must allow in the design for a certain degree of movement of the wall into the passive soil in front of the key so that the resistance can be generated in this soil at the toe. Also I believe that the passive face must be protected from the effects of weathering and moisture absorbtion (especially in clays).&nbsp;&nbsp;Therefore, it is best to cover the passive key material with a part of the wall base slab.&nbsp;&nbsp;Also, good routing of the through-wall drainage away from the toe is essential in order to prevent swelling/softening of clay toes.<br><br>Regards <p>Andy Machon<br><a href=mailto:Andy@machona.freeserve.co.uk>Andy@machona.freeserve.co.uk</a><br><a href= > </a><br>