Foundation-Interface Shear Strength of Pile in Undrained Soil

In undrained soil, the interface shear strength of pile is solely dependent of the soil cohesion.

Adhesion factor is added into the equation to account for the roughness of pile-soil interface.

This process is also known as alpha method in pile design.

For displacement pile, adhesion factor can be determined based on the experimental result from Semple & Rigden (1984) and Kalsrud et al (1993).

As for non-displacement pile, adhesion factor is defined based on the data presented by Skempton (1959), Weltman & Healy (1978) and Stas & Kulhawy (1984).