Head embedment in Broms pile lateral capacity theory for cohesionless soils

The method by Broms for the evaluation of lateral load capacity of piles and shafts is well known to every geotechnical engineer and still used nowadays, at least in some simple situations. It applies to piles with a restrained head at the ground level, or a free head at or above the ground, both for cohesive and cohesionless soils. In this paper the Broms theory for cohesionless soils is extended to account for an arbitrary position of the pile head, considering embedded as well as over-ground restrained and free pile head. Explicit analytic expressions for the collapse load and the geometrical parameters of the problem are given, making use of the geometric approach by Nickalls to the solution of the cubic equation. The relationships between embedding and over-ground situations on one hand, and restrained and free head cases on the other are discussed, some simplified calculation procedures being suggested.