Construction organization design of a tunnel in Sichuan Province
1、 Project overview xx Hydropower Station is located in Xiangcheng County, xx Prefecture, xx Province. It is the second stage power station in the "one reservoir and five levels" development plan for the main stream of Shuoque River, with an installed capacity of 93MW. The hydropower station adopts diversion type development, which is composed of head hydroproject, diversion system and plant hydroproject. The gate site is located about 180m downstream of the mouth of Buyangou Ditch, and the plant site is located at the right bank of Shuoque River about 1000m upstream of xx. The distance along the river between the gate site and the plant site is about 22km, and the length of the headrace tunnel is about 15.48km. In order to meet the construction requirements of the headrace tunnel of xx Hydropower Station, 7 construction adits are arranged along the headrace tunnel, and one construction adit (8 # adit) is arranged at the lower flat section of the penstock. Among them, the 1 # and 2 # construction adits are located at the upstream of Zhangji, which can only be started after the access conditions of the Zhangji xx gate site section of the off-site traffic project of Guwa Power Station are initially met. The 3 # - 8 # adits are located at the downstream of Zhangji, which can be started by relying on the existing rural roads and S217 Provincial Highway. The section type and size of 1 #, 2 #, 5 # and 6 # adits are designed as per single lane, and the section size is 4.5 × 5.0m (city gate type, width × height); The section type and size of 3 # and 4 # adits are designed as two lanes, and the section size is 7.0 × 5.5m (city gate type, width × height); The section type and size of 7 # and 8 # construction adits are designed to be 6.0 × 6.5m (city gate tunnel type, width × height), taking into account the requirements of transport butterfly valve and pressure pipe respectively. At present, 3 # bridge, 5 # and 6 # construction access roads have been successfully opened to traffic. Bid section B of our company is 632m for 4 # adit and 342m for 5 # adit.
