9. Hydraulic uplift of surface foundations

In some cases, surface foundations may be subject to hydraulic ground failure.

• The most common failure modes due to hydraulic phenomena are :

  • Global hydraulic uplift due to Archimedes' thrust: this phenomenon occurs when the water pressure under a structure or a layer of low-permeability soil exceeds the average vertical stress;

  • hydraulic uplift due to cancellation of effective vertical stresses: this phenomenon occurs when upwardly directed flow forces oppose the weight of the soil, reducing the effective vertical stress to zero. The particles are then carried upwards, and failure occurs by bubbling;

  • internal erosion, when water drags soil particles within a layer or at the interface with the structure. This erosion can develop...