Photo shows the exterior of the underground utility tunnel.

Photo shows backfilling of the underground utility tunnel.

Photo shows the interior of the underground utility tunnel.

    On April 23, the first main-section construction of the urban comprehensive utility tunnel project of the Jiazhou Road project in Sichuan Tianfu New Area, undertaken by China 19th Metallurgical Group, was completed and backfilling began. The project has a total length of about 2.3 kilometers, of which the underground comprehensive utility tunnel is about 2.2 kilometers long, using a total of 14,082 tons of steel reinforcement. This includes 220.8 tons of Grade I steel HPB300 Φ8 mm-Φ10 mm and 13,861 tons of Grade III steel HRB400 Φ14 mm-Φ28 mm. The utility tunnel has a double-compartment structure. Compartment 1 contains cable, communications, water distribution, reclaimed water and other pipeline routes as well as maintenance passages; Compartment 2 contains water transmission, reserved reclaimed water, reserved energy and other pipeline routes as well as maintenance passages.