怀邵衡沅江特大桥12＃主墩深水基础施工技术

摘要

沅江特大桥12＃墩桥址处地质为卵石土和泥质砂岩，承台埋入岩石最深达8 m，封底混凝土厚度2．8 m，围堰需要下沉的深度最深10．8 m，卵石土和泥质砂岩地质，围堰无法下沉，墩位处钻孔平台汛期设防水位超过20 m，沅江河流无大型施工船舶和大型水上起吊设备，基础施工要求1年内完成，工期非常紧张，施工难度大。采取各种技术措施，有效地解决了上述施工难题。%No.12 main pier of Yuanjiang Bridge is located in the geology with gravel soil and argillaceous sandstone,the deepest part of pile cap embedded in rock is up to 8 m,the thickness of subsealing concrete reaches 2.8 m,and the dee-pest sinking depth of cofferdam is 10.8 m.Due to the gravel soil and argillaceous sandstone,it is unable to sink cofferdam. The water level of flood prevention for bored platform is more than 20 m during the flood season.Being lack of large-scale constructing ships and water lifting equipment,the project duration is very nervous and with huge difficulty under the re-quirements of one year to complete the foundation construction.Finally,we take all kinds of technical measures to effective-ly solve the construction problems of the above.