Enayam Port

Tamil Research Institute
RAPID TECHNO-ECONOMIC FEASIBILITY REPORT FOR
DEVELOPMENT OF COLACHEL PORT AT TAMILNADU
FINAL REPORT
others, this fact can influence the geotechnical design of pile foundations (the total pile length will vary with the
specific location of the rock).
Thus, the proposed profile must be assumed just as a first approach of the average geotechnical conditions at
the site, to be confirmed in further phases of the project.
7.4.6. Geotechnical risks
From a geotechnical point of view, the main risks to be considered in further stages of the project can be
summarized as follows:
• Presence of rock or hard materials in the area to be dredged, which would involve an important impact on
the cost and performance of the dredging works.
• Presence of soft or very loose materials in the locations of breakwaters, berths, or earthfills, which may
require special foundations or ground treatments to guarantee the structural requirements.
• Steeply sloping seafloors and accompanying down-slope soil movements can cause additional lateral pile
forces in the down-slope direction. Also, steep sloping makes the area more vulnerable to instability
induced by the seismic activity of wave forces.
• Scouring of near-surface soils can occur and can be accentuated in the vicinity of piles. The extent of the
scouring depends on the velocity of seafloor currents, the type of soil and the size and configuration of pile
groups.
• Earthquake-related hazards should be assessed in seismically active areas. Earthquake motions may cause
partial loss of strength or complete liquefaction in loose granular soil zones, essentially removing soil
support developed in these zones.
• Gneisses are more susceptible to weathering compared to massive charnockites. Erosion in gneiss areas is
higher than in charnockite areas, therefore rivers in gneiss areas are prone to transporting more sediments
than those in charnockite areas.
The table below shows a general assessment of the geotechnical risks described above. More detailed analyses
should be developed in further stages of the project, based on the results of the geotechnical field investigation
(boreholes, trial pits, geophysical profiles, etc.).
% rock near surface
Thick deposits of
sediments
Steeply sloping
seafloor
Type of rock (weather
susceptibility)
Grade Low Low Low Moderate
7.5. LAND AVAILABILITY
Table 16: Geotechnical risks.
As the port is to be developed entirely on reclaimed land, no land acquisition is envisaged for the port
development. However, the project shadow area can impact fishermen dwellings.
Coastal land from Colachel to Enayam would change to a port area. As a result of the Project development, this
part of the sea coast and beaches would be permanently lost during the construction and operation of the
Project.
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