Construction Methodology and Environmental Monitoring for the Deepwater Breakwater on the West Coast of India

The upcoming Vizhinjam International Deepwater Multipurpose Seaport is a flagship project of the Government of Kerala (GoK). It has the potential to become a world-class container transhipment hub primarily for Indian Sub-Continent cargo (ISC) servicing entire India and some of the neighbouring countries. Since it is located on an open coast, a breakwater is being built to provide sufficient tranquillity for the safe loading and unloading of cargo from vessels. The length of the rubble mound breakwater is 3100 meters, which includes a wave wall to protect the harbour basin from waves and swells. The road at the top of the breakwater has a width of 10m. The outer part of the breakwater is designed to withstand a significant wave height of 4.7 meters.

The methodology of construction of the breakwater is explained. For the core of breakwater, notably for underwater placement, the placed bulk density is the most important indicative material parameter, as it relates closely to shear strength and possible settlement as well as to permeability. It is governed by the grading width and particle shape. Detailed studies on core gradation for several samples were performed. A detailed study on sedimentation patterns and shoreline evolution due to littoral movement was carried out as a part of environmental monitoring and the sedimentation inside the adjacent fishing harbour and nearby areas for the various phases of port development are found to be very minimal.