The response of piled buildings to deep excavations

This means that the soil around the piles is subject to vertical settlements and horizontal displacements, similar to the ground surface. In stress terms the vertical and horizontal stresses around the pile decrease. Outside the active zone (see Fig. 1 in the case of sandy soils) the stresses are assumed to remain approximately constant. For end bearing piles which settle less than the surrounding soil, negative skin friction may develop in the active zone.