龙滩水电站32号坝段倒垂孔成孔的施工

Overturned Hole Engineering at 32# Dam Section of Longtan Hydropower Station

龙滩水电工程左岸大坝32号坝段布设的倒垂孔在钻孔过程中两次遭遇锚索,埋管部分边浇筑边埋设,对倒垂孔成孔的有效孔径(有效孔径设计要求为150 mm)影响较大,为此采用多种方法多次进行纠偏从而成功穿过锚索,同时也未影响坝体混凝土浇筑进度。

The overturned hole at 32 # dam section on the left bank of Longtan Hydropower Station encounters anchor cable twice during drilling process. The embedded pipes are placed and embedded simultaneously, having considerable impact on effective aperture of the overturned hole （the effective aperture as designed shall be 150mm）. As such, a number of methods for deviation rectification of the overturned hole have been adopted so that it can successfully go through anchor cable without affecting concrete placement of the dam.