Foundation depth

[geotechniqa]

-when the depth of foorting (2 m) is higher than the width (1 m) can the classicaa bearing capacity relation be applied

 

[civilperson]

yes

 

[geotechniqa]

i do not think so because the classical bearing capacity relation developed by Terzaghi was proposed for shallow foundation for which, as Terzaghi defines, the width is smaller or equal to the depth

 

[dgillette]

Shouldn't be a big problem. Typical practice treats the 2 m of soil as surcharge acting at the footing's base elevation. That assumes there is no shearing resistance within the top 2 m, so it's probably a tad conservative. Besides, bearing capacity rarely governs allowable anyway - it's usually settlement.

 

[BigH]

Typically, from recollection - "deep foundations" start at a depth/width ratio of about 5.