Settlement measurements optimising construction of a breakwater on soft soil

Abstract

The need of an improved harbour access resulted into the construction of two new rubble mound breakwaters in Ostend, Belgium (Verhaeghe et al., 2010). Extensive soil investigation during the design phase of the breakwaters showed that the most northern part of the western breakwater is located in a zone containing a thick upper layer of soft material. To deal with the bad soil characteristics, a very strong geotextile was used to serve as a kind of armouring of the breakwater. An extensive analysis was carried out to determine how fast construction could go on, avoiding overall geotechnical failing, and to determine the settlements to be expected. During construction of the western breakwater, extensive settlement measurements were performed. This paper describes the settlement calculations performed with Plaxis2D versus the settlement measurements performed on site, leading to an optimised phasing of the construction works.