Construction of The United Arab Emirates’ first road tunnel, the Dhs42,950,000 ($11.9m), 1.2km long Wadi Middiq to Gillay Tunnel, is well under way with contractors reporting a drill and blast advance of 6m a day.
Contractor JV of Belgian-based Six Construct and Austrian AST started excavation at the end of April and had reached 210m on the top heading as T&TI went to press.
Prior to the main tunnel excavation, specialist rock drilling and blasting subcontractor Gulf Rock had to create an east access portal. Using Atlas Copco equipment, the contractor began in February this year with drilling rigs on two benches, 6m and 12m high respectively, with a drill pattern of 2.4m spacing and 2.2m overburden. Blasting three times a week, removing an estimated 3,000m³ of rock a day, the portal was completed at the beginning of April.
The main tunnel now under construction is also a drill and blast drive. The finished single tube twin lane tunnel will be 9.7m high and 13.5m wide. The drive, with a February 2002 completion date, is through gabbro with permanent support provided by sprayed concrete, steel rockbolts and lattice girders. Secondary lining with in situ concrete is scheduled to start on 1 October and take eight months.
Part of a major road project to link Dhaid with Kalba on the east coast, the tunnel, designed by UK consultant Halcrow International Partnership, is being financed by the Ruler of Sharjah and executed by the Directorate of Public Works of Sharjah.
