Sri Lanka, July 24 -- Recently, excavation work on the 27.7-kilometer irrigation tunnel in Sri Lanka - the longest of its kind in South Asia undertaken by CSCEC - was completed.The tunnel is also the longest overseas tunnel ever bored by CSCEC using tunnel boring machines (TBMs). Once operational, it will serve as the main water channel for Sri Lanka's south-north water diversion project, delivering about 100 million cubic meters of water to North Western Province every month. The project will provide irrigation water to 73,800 hectares of farmland and supply domestic water to 375,000 households along its route.About 26.6 kilometers of the tunnel run through hard rock, and boring such a long, single-ended stretch posed the project's biggest...