泰州大桥南锚碇巨型沉井排水下沉施工技术

Construction Technology for Draining-sinkage for South Caisson Anchorage to Taizhou Yangtze River Highway Bridge with Large-sized Sunk Well

研究目的:随着国内经济发展及大型沉井基础的开发应用,泰州长江公路大桥南锚碇沉井基础长67.9m,宽52m,高41m,在长江岸边的冲积沙土地质中下沉,选用排水下沉和不排水下沉相结合的两个施工方案,如何确保沉井结构和附近建筑物以及长江大堤的安全是关键;本文仅介绍沉井钢壳拼装,混凝土接高,深井降水和泵吸挖土的排水下沉施工方案,达到安全优质快速下沉的目的。研究结论:采用排水下沉,沉降系数大,深井降水效果好,泵吸挖土效率高、出泥量大,下沉速度再创新高;安全可控制,质量有保证,环境易达标;沉井接高浇筑质量和下沉偏差都得到了很好控制,达到规范标准;通过回灌水附近建筑物和长江大堤的沉降得到有效控制,确保了人民生命财产安全。采用深井降水和泵吸挖土的排水下沉方案,能达到安全快速施工大型沉井基础的目的,同时也掌握了大型沉井排水下沉的关键施工技术。

Research purposes： With the economic development in China, more and more large -sized sunk wells have been used. For instance, the 67.9 m long, 52 m wide and 41 m high base of south caisson anchorage to Taizhou Yangtze River Highway Bridge had to be sunk in the alluvial sand on the riverbank by draining - sinkage along with non - draining - sinkage. How to ensure the safety of sunk well structure, surrounding buildings and Yangtze River dam is the key point. The introduction is given in this paper to the draining sinkage scheme, including the steel caisson assembly, concrete joint height and pumping water and removing soil with deep well. Research conclusions： Using draining sinkage can guarantee the grouting quality for concrete joint height and can effectively control the deviation of sinkage, with the features of large sinking coefficient, good precipitation effects of deep welt, perfect pumping efficiency of the excavator, removing large mud and high sinking speed. And the subsidence of the surrounding buildings and Yangtze River dam is controlled effectively by filling water.