Key Techniques for Construction of East Anchorage of the Lingdingyang Bridge on Shenzhen-Zhongshan Link

The Lingdingyang Bridge is a (580+1666+580m) two-tower three-span sea steel box girder suspension bridge. The east anchorage adopts a figure eight-shaped ground connecting wall foundation. The ground connecting wall has a diameter of 107.1m and a width of 65m. The wall thickness is 1.5m. the maximum depth of the wall is 63m, the embedded medium weathered granite depth is 5m. The overburden thickness is nearly 50m, the bedrock depth above 80Mpa is 10m, and the excavation depth of the foundation pit is 42m. The anchor body is a diamond shaped anisotropic anchor body, with a total volume of 93000 m³. The anchorage foundation adopts “locking steel pipe piles + I-shaped sheet piles + parallel wire ropes” combined island-building cofferdam, and the diameter of the island is 150m. There are 79 groove sections in the ground wall. Three-axis mixing piles are used to reinforce the joints and both sides of the groove wall before grooving. The technique of alternately forming grooves by “rotary drilling + groove milling machine” is adopted. The deep foundation pit is unearthed together with the excavation portal frame and the telescopic boom excavator, and the lining is constructed with the hanging form. After the excavation, the waterproof effect of the ground connecting wall is obvious, and the foundation pit is safe and reliable. The anchor body is constructed with a layer of 2m with a large amount of limestone powder concrete, and a 2m post pouring section is set at the same time. The maximum temperature is 65 °C, and the crack control effect is obvious.