SETTLEMENT OF A HIGH EMBANKMENT AND OVERPASS STRUCTURES IN OTTAWA

Abstract

Settlement observations have been conducted over a 5-year period on a 20-ft-high earth embankment and 2 highway overpass structures founded on spread footings over a thick deposit of Leda clay. The applied stresses were considerably less than the overconsolidation pressure of the clay. In the five years since construction, settlements of approximately 12 cm have occurred, of which about 4 cm occurred immediately. The observed settlements are compared with settlement predictions on the basis of various types of laboratory tests. The observations indicate that significant settlements occur on a long-term basis and can be attributed to a slow yielding of the clay structure. Piezometers failed to detect any excess pore water pressure due to slow process of consolidation.