Rubble mound breakwaters for the new port of Ennore (India) - Evaluation of construction

Abstract

At the east coast of India, 20 kilometres north of Chennai, a new satellite port has been designed and is currently under construction. The project is called the Ennore Coal Port Project. Complete design and supervision of the construction is carried out by HASKONING Consulting Engineers and Architects. The objective of this graduation project was to evaluate the construction processes of two major contracts of the port construction, viz. quarrying and transportation of rock and breakwater construction. Two rubble mound breakwaters were designed to withstand a wave height with a return period of hundred years with minimum damage. This resulted in a protection of a single layer Accropode blocks with a maxim weight of 15 tonnes at the deepest section of the northern breakwater. The southern breakwater is protected by natural rock with a maximum grading of 5-12 tonnes. The breakwaters are built by marine based methods (up to -4m Chart Datum) and by land based methods above this level. Rock for the breakwaters is quarried at Karikkal, a for this project developed quarry, situated 120 km west of Madras. The rock is sorted into various gradings and then loaded on especially for this purpose constructed skips. The skips are transported on trucks for the first 25 km to a transfer station. From there on the skips will be placed on trains, which transport the skips directly to a stockpile area at the port site. The empty skips are then transported back to Karikkal. A period of three and a half months of the graduation project was spent on the construction site in India. This period was mainly used to gather information to be worked out further in the Netherlands. Deviations in the construction process from earlier made assumptions were investigated. In the Netherlands an analyses of the effects of these deviations on the operational processes, time schedules and realised construction was done. The analyses shows that for the processes of quarrying and transportation of rock, as well as for the processes of breakwater construction, there are a number of deviations in the actual construction phase from earlier planned processes (such as: realignment of the north breakwater, use of equipment that is not the most suitable for the job and working without an approved work method statement). The main effect of the deviations are delays and difficulties during the production process itself (such as: necessity for resurveys and absence of a supervision tool). The deviations are further examined and some recommendations are given to the Client.