广佛肇高速公路北江大桥基础施工关键技术

北江大桥33#墩采用钻孔灌注桩和分离式承台,承台位于风化泥岩范围内,且墩位处水位较深,流速较大,基础施工技术难度大。经研究,确定采用了“钻孔平台+钢板桩围堰”的施工方法。钢板桩围堰施工采用了旋挖钻机引孔及水下高压注浆的施工关键技术,并且承台范围内基岩开挖采用预开挖及围堰干挖法取土的施工方式,解决了无覆盖层且嵌岩的低桩承台施工难题。

Key Techniques for Foundation Construction of Beijiang Bridge in Guangfozhao Expressway

The 33# pier of Beijiang Bridge is adopted of bored pile and separated base slab. The base slab is located in the range of weathered mudstone, the water level at the pier is deep and the water velocity is fast. The foundation construction technology is difficult. After research, the construction method of "drilling platform + steel sheet pile cofferdam" is determined. The key technologies of rotary drilling rig pilot hole and underwater high-pressure grouting are adopted for the construction of steel sheet pile cofferdam, and the construction method of pre-excavation and cofferdam dry excavation is adopted for the excavation of bedrock within the range of base slab, which solves the construction problem of low-pile base slab without coating and rock-socketed.