Long-term performance of an embedded retaining wall with a stabilizing base slab

In 1993, a field study was commenced to investigate the in-service performance of a bored pile retaining wall constructed with a stabilizing base slab below the carriageway in front of the wall. The wall was founded in London Clay and constructed at South Woodford in London in 1976. Instruments were installed in front of and behind the wall as well as in a free field location to provide an assessment of both the lateral stresses acting on the wall faces and the in situ lateral stress existing prior to construction. Total lateral stresses were measured using push-in spade pressure cells, a Marchetti dilatometer, a self-boring expansion pressuremeter and a self-boring load cell pressuremeter. Pore water pressures were recorded using piezometers incorporated in the spade cells. In this paper, the field measurements are presented and discussed in the light of limit-equilibrium-based calculations typically used in design.