The planning and implementation of a site investigation for a highway in tropical conditions in Fiji

Summary The paper outlines the planning and implementation of a site investigation carried out on a limited budget for 110 miles of proposed new highway in Fiji. A comparison is drawn between the cost of investigation of earthworks and general foundation conditions, rock materials, and engineering structures, estimated during the planning stage by allocating funds in the same proportion as the estimated construction cost, and the actual cost of investigation of each. The programming and staffing of the investigation are considered. Examples are quoted showing how economical results were obtained by the use of geotechnical expertise in tropical soils. Attention is drawn to the method of classifying residual soils in grade zones developed during the investigation according to their geotephnical properties. Problems of laboratory investigations of tropical materials are considered. The value of large scale tests such as trial embankments as a means of assisting in the preparation of a realistic compaction specification for residual soils, and also as a means of testing construction methods in swamp areas are discussed.

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