托口水电站坝后护岸修复设计及无围堰施工方案

托口水电站坝后护岸水毁严重,范围大、冲坑深,修建临时围堰进行干地施工投资较大。经方案比选,采用旋挖钻孔机械在堆渣平台上钻孔,浇筑C30混凝土灌注桩,桩顶设C25混凝土承台梁,梁内测布置一排Φ 32水泥砂浆锚杆,长9.0 m,入岩长度不小于5.0 m。既缩短了工期,又在工程质量和经济方面都取得了较好的效果。

Design of the Non-cofferdam Construction Scheme for Behind-dam Revetment Repair Work in Tuokou Hydropower Station

The revetment behind the main dam in Tuokou Hydropower Station is seriously damaged by discharge flow.Considering the large extent and depth of the scour hole,the investment of the traditional dry land repair scheme with temporary cofferdam could be excessive.Thus,an underwater single row continuous concrete cast-in-place pile construction scheme without cofferdam is proposed.The rotary drilling machine is adopted to drill boreholes on the residue platform and C30 concrete cast-in-place piles are poured.Then,C25 concrete bearing beams are constructed at the top of the piles,and a row ofΦ32 cement mortar anchor rods with the length of 9.0 m and the minimum rock-penetrating depth of 5.0 m are arranged in the river bank side of the beams.The proposed scheme not only cut down the construction time,but also achieved good results in both construction quality and economy.