Technical Tour to the Southern Transport Development Project (August 11, 2007)

A 124 km. long expressway connecting the Capital city of Colombo with the Southern city Matara is now being constructed with the objective of reducing the travel time between the two cities from the current 4 hrs to 1 hr and to boost up the socio-economic development of the southern region of Sri Lanka by providing access to major cities and towns in the region. The road trace has been divided into three packages (as three different contracts) as: Kottawa to Dodangoda, Dodangoda to Kurundugaha Hetepma and Kurundugaha Hetepma to Matara .

Construction of the expressway involves deep cuttings in hilly terrain and high embankments in low lying marshy areas. Deposits of soft clays and extremely soft peaty clays exceeding 5m in thickness have been encountered in some stretches of the expressway.

In the southern segment from Kurundugaha Hetepma to Matara where the work is in an advanced stage, measures such as: replacement of extremely soft peaty clays up to 5 m thickness, use of prefabricated vertical drains and use of piled embankments were adopted to overcome the weak soil conditions. Stabilization of deep cut slopes and soft ground improvement works are now in progress.

In the two segments from Kottawa to Dodangoda and Dodangoda to Kurundugaha Hetepma techniques such as: heavy tamping with fibre drains, vacuum consolidation, preloading with vertical drains are being tried out at different locations. There are several well instrumented trial sections on these ground improvement techniques.

The participants will be guided through number of sites where they will be able to witness these activities and recorded performances of the already completed geotechnical work.

Improvement of Soft Ground by Heavy Tamping 

 Prefabricated Vertical Drains Used in Soft Ground Improvement

Anchored Earth Retaining Structures for Bridge Abutments