Extensive jet grouting has been used to control settlements of sensitive buildings for the new Izmir natural gas power plant. The power plant, 60km north of Izmir on the Aegean coast, is sited on an ancient lagoon infilled with 16m to 30m of fine alluvial lake sediments, mainly gravelly and sandy clay, overlying volcanic tuff.
Site investigations and analysis predicted settlement of some structures of up to 100mm and differential settlement up to 50mm. Kasktas installed 600mm diameter, 12m long jet grout columns on a grid varying from 1. 5m to 4. 5 spacing, making a total of 78,000m. Twelve test columns were installed at six locations across the site. Six were cored to test for continuity and strength, and pull out tests to loads of 900kN were carried out on the other six. Additional test columns determined the jet grout operational parameters for the working piles. One in every 50 jet grout column was cored, and integrity testing was carried out one in every 20.
Kasktas' £2M contract, which included the site investigation, began in November 1999 and finished in March this year. The power plant will be built and operated by InterGen and Bechtel-Enka joint venture.