The Hindu Business Line : IIT study on soil conditions — `Proposed site for Kochi terminal need to be raised '

THE preliminary analysis of the soil strata conditions at the proposed container transhipment terminal site carried out by the IIT, Chennai, has recommended that the site is required to be raised to a minimum elevation of above 3.5 metres so that construction work can be carried out independent of tidal variations.

The data made available also indicate presence of dark grey soft silty clay with liquid limit and this layer is certainly inadequate to support the proposed facility without any improvement, the Geo Technical Division of the IIT said in its report submitted to the port.

The report said that both the areas at Vallarpadam and Puthuvypeen were low lying with average reduced level of over 1.5 metres above mean sea level. During high tides, these areas may get inundated by tidal waters and the site therefore needed to be raised to carry out the construction work for the foundation of the proposed terminal and container parking yard at the port.

It also suggested certain major challenges to be examined while designing the foundations. They are: There are possibilities of deep seated slope failure at the edge of the filled area unless proper strengthening measures are adopted; all structures sensitive to settlement such as rail beam for container handling crane has to be supported on pile foundation; the pile foundation will have additional load due to negative drag force which will considerably reduce the effective capacity of piles.

The port authorities in November last year had entrusted the IIT to examine the soil strata conditions based on the data available and suggest suitable methodology to be adopted for improvement of the soil strata, design of pavement and estimate of settlement. The port proposes to develop transhipment terminal and container parking yard by reclaiming land with dredged material.

Part of the area has already been reclaimed. The additional fill required will be mainly the dredged material during capital dredging or during maintenance dredging. The area was partly reclaimed in the year 1984 and subsoil investigation was carried out in 1991 for the preparation of feasibility report.

The area at Puthuvypeen is area of accretion and filled up by the seabed sediments due to the natural phenomenon of littoral drift. In this area also, soil investigation has been carried out in the past for setting up L&G Terminal and also for the establishment of a tank farm by Kochi Refineries Ltd.