Use of the observational approach for embankment construction on organic soil deposits in Sri Lanka

Abstract

Road embankments on organic soil deposits cause stability issues during the construction stage and consolidation settlement problems during the post construction stage. As the conservative approach, which designs road embankments using unfavourable or prismatic ground conditions, becomes uneconomical or not feasible for construction of road embankments on organic soil deposits observational approach is very often used for such design and construction. In the observational approach, the most probable or more optimistic ground conditions are considered in the initial design. The risks associated with using most probable soil properties are managed by reviewing the initial design through the analysis of the observational data obtained during the construction stage. In this regards, analysis tools to assess the stability of the embankment during construction stage and the estimation of the degree of consolidation during ground improvement phase are extremely important. Even though there is large number of analytical methods available to use for the data analysis, not much research is done to identify the tools relevant to the organic soft soils found in Sri Lanka. This research is aimed at investigation of the analytical tools that can be used to analysis of settlement monitoring data obtained during the implementation of the observational approach for construction of the road embankments over the soft soil deposits in Sri Lanka.