强泄洪河道中全淹没式取水头部的设计与施工

Design and Construction of Fully-submerged Intake Head in Strong-flooddischarge River

在新安江大坝下的河道中建设全淹没式取水头部,需解决强泄洪状态下的结构稳定性和全水下作业的施工难题。设计采用钢筋混凝土箱墩+灌注桩的桩架式取水头部,计算了大坝校核洪水流量下的水流冲击力,复核了桩基抗水平承载力,确保了结构安全性。取水头部施工,采用钢制箱模/陆地焊接/水面吊装/水下浇捣成型的施工工艺,大大减少了水下作业的工程量和难度。水面作业平台采用钢管柱+钢斜撑+钢制平台的钢结构栈桥形式,有效抵抗住施工期的泄洪冲击,保证施工顺利进行。目前取水头部已稳定运行一年多,证明了设计与施工方案的合理性。

A fully-submerged intake head was built in the river under the Xin＇ anjiang dam. The structural stability under strong-flood-discharge and the method of full-underwater construction were theissues existing in construction. In order to ensure the structural security in this project, we designed a re-inforced concrete pierbox and caisson pile, calculated the impact force on the intake head under dam＇ scheck-flood, and double-checked the horizontal bearing capacity of pile. The construction technologiesincluding steel pier mould, welding on land, hoisting above river surface and underwater casting were a-dopted. As a result, the underwater work load and the construction difficulty were decreased greatly. Thesteel structure trestle bridge form composed by steel pipe column ＋ steel bracing ＋ steel platform was a-dopted in surface work platform, which can effectively with stand the flood impact during construction pe-riod. Therefore, the smooth progress of construction could be ensured. This intake head has been put intooperation for more than one year, the design and construction scheme proved correct.