Highways in various parts of the world are often upgraded from a rural road by raising the profile grade over an existing road. Without the original design and construction details, the rehabilitation and maintenance of these highways become very difficult particularly in the event of an embankment failure. Repeated failures on a section of Highway 2 had been occurring for more than 25 years. This stretch of highway was constructed in the early 1930s and mid 1940s over the old road without providing any drainage facilities to intercept surficial seepage through the old roadway fill and redirect it away from the slope. The reconstruction work was further complicated due to the presence of variable thickness of organic silt and peat near the toe of the embankment. The stability of a highway embankment can only be maintained if the foundation soil remains in a relatively dry condition. The failure to provide a adequate drainage to remove water away from the slope may result in an increase of moisture content of the fill. This can create problems such as slope instability and ongoing maintenance activities for an embankment constructed with cohesive material. (A)
Abstract