Lateral Loads on Piers due to Soil Creep

[ckissick]

When giving recommendations for a pier and grade beam foundation, what's a good way to account for lateral loads acting against the tops of piers and on grade beams due to soil creep on slopes?

In my case, it is a 2:1 slope, stiff expansive clay, and I estimate the upper 3 feet is prone to creeping.

 

[GeoPaveTraffic]

Creeping soil can impart a tremendous amount of load to relatively stiff foundations. If the soils are are likely to try and move, then the maximum load they can impart is the passive pressure that the soil can develope by acting on the piers and grade beams. Yes I understand that a lot of movement has to occur to mobilize full passive pressure, but if other actions aren't taken to prevent the soil from creeping then it is likely that eventually full passive will be reached.

Unless your piers and grade beams are very large it is likely that they will be move significantly under this imposed load, very possibly more than is desirable for the supported structure. Therefore, the best solution is probably to address this soil creep issue so that it does not occur.