ABSTRACT:

A large coal stockpiling and transhipment development at Paradip, on the Bay of Bengal, involved raising of a soft soil site using hydraulically placed dredged fill. This case history describes the investigation, design, construction, and settlement performance the stockpiling area. Limited geotechnical data lead to pragmatic design with implications for reliability of settlement performance. Investigation and design included two trial embankments, drillholes, static cone penetration profiling, and laboratory tests. Design formulae for settlement magnitude and time were developed using theoretical and empirical relationships. Settlement plates and pneumatic piezometers were used to calibrate and update the design relationships during construction. Design of the fill placement scheme was based on geotechnical constraints, particularly consolidation time. Despite losing most instrumentation by the completion of preloading, performance data was sufficient to achieve preloading with an acceptable level of reliability. Application of the observational method at a difficult site in a remote location has demonstrated that reliable outcomes can be achieved provided they are based on an established conceptual framework.

INTRODUCTION AND SETTING

Paradip is a dredged deepwater harbour located on the Bay of Bengal approximately 400Êkm southwest of Calcutta, India (FigureÊ1). A 20ÊMt/a coal transhipment facility is being developed to service the domestic power coal market. The site lies within a large delta adjacent to the main distributary channel of the Mahanadi River. The geology of the coastline area includes dune sands, a basal marine transgressive silty sand and Recent estuarine and alluvial sedimentation. The wave-dominated delta includes abandoned channels filled with fine sands, silts, and clays. Under the site at about 15Êm depth is the Pleistocene disconformity, an oxidised and fissured stiff sandy clay and dense sand, which is underlain by a thick sequence of older deltaic and marine transgressive sediments. FigureÊ1 also shows a general view of the project site.

This content is only available via PDF.
You can access this article if you purchase or spend a download.