万州长江三桥深水区钻探定位施工方法探讨

Positioning method for geologic survey in deep water area of Wanzhou No.3 Yangtze River Bridge

在万州长江三桥地质勘察期间,三峡库水位为175 m,勘探区最大水深达95 m,水深浪大给水上钻探定位造成了很大困难,提高钻探定位精度是勘探的难点。根据设计要求,在桥墩及其周边共布置了18个水上钻孔,钻孔的平面精度要求小于0.5 m。钻探的主要工艺流程为:钻船拼装→抛锚→钻孔定位→下保护管→钻孔→封孔→起保护管→起锚→钻船移位等。通过认真分析,精心的施工组织,钻探定位精度满足规范与设计要求。详细介绍了钻船的定位过程,可供同类工程参考。

During the geological survey period for Wanzhou No. 3 Yangtze River Bridge, the impoundment level of the Three Gorges Reservoir was 175m, and the maximum depth of exploration areas is up to 95m, the difficulties of drilling positioning are caused by the deep water and big waves, therefore the improvement of the accuracy of drilling positioning is the difficulty of this exploration. According to the design requirements, 18 water drilling holes were arranged at the pier and its surroundings, and the requirement of plane accuracy was less than 0.5m. The main drilling processes were as follows： assembling the drilling ship, anchoring, positioning and installing of protective tube, drilling, sealing drilling hole,uplifting of the protective tube, weighing anchor, shifting of drilling ship and so on. The accuracy of drilling positioning can meet the requirement of standard and design after the careful analysis and meticulous construction organization. The positioning of the drilling ship is introduced in detail, and can be referenced for similar projects.