软土地基上长管砂袋围堰变形与稳定性研究分析——以广州南沙明珠湾区跨江通道工程施工围堰为例

Study and Analysis on Deformation and Stability of Long-pipe Sand Pocketed Cofferdam on Soft Soil Foundation

摘要:

围堰施工是跨江通道工程水域侧基坑实施的前提条件和关键环节，天然软土地基淤泥质软土层厚度大、承载力低，采用长管模袋砂围堰能较好地适应软土地基的变形和抵抗水流的冲刷。以广州南沙明珠湾区跨江通道工程施工围堰为实例，采用数值分析模拟长管砂袋围堰的施工全过程，计算产生的沉降变形及基坑开挖对围堰的影响。结果表明，围堰施工时堰底内侧沉降明显，外侧坡脚处水平外移及隆起，基坑开挖引起围堰内侧变形明显大于外侧。

Abstract:

The cofferdam construction is the precondition and key link in the implementation of foundation pit at the side of the water area for river crossing project. The silt soft soil layer of natural soft soil foundation has large thickness and low bearing capacity. The use of long-pipe sand pocketed cofferdam can be better adapted to the deformation of soft soil foundation and can resist the washing of water flow. Taking the cofferdam construction of Guangzhou Nansha Pearl Bay Area River-crossing Channel Project as an example, the whole construction process of long-pipe sand pocketed cofferdam is numerically analyzed and simulated to calculate the influence of produced settlement, deformation and pit excavation on the cofferdam. The result shows that the settlement at the inner side of cofferdam bottom is obvious during the cofferdam construction, and the horizontal displacement and uplift are at the foot of lateral slope. The deformation of the inner side of cofferdam caused by the pit excavation is obviously greater than that of the outer side.