不同接头类型地下连续墙受力特性研究

Study on Stress Characteristics of Diaphragm Wall with Different Joint Types

以浦东机场南区地下交通枢纽工程为例,通过建立数值模型分析了不同地下连续墙接头在基坑工程的应用效果,并对比选择了最佳接头类型。研究结果表明:地下连续墙接头部位的水平位移随着基坑的不断开挖而增大;接头位移在基坑开挖至底部时达到最大值66.3mm,在开挖过程中水平位移较大的部位基本位于基坑的中上部,要预先做好预警工作和应急预案,避免发生大面积渗漏的情况;接头类型不同时,地下连续墙对应部位的水平位移有所差异,选择刚性接头时地下连续墙传递应力的能力更好,承载能力更强,位移变形较小;随着基坑的开挖,地下连续墙采用H型钢接头和十字钢板接头时的水平位移变化趋势基本一致;支撑轴力在接头水平位移有显著降低的第3道混凝土支撑部位时的值较大;地下连续墙接头类型同时会对接头部位的稳定性和基坑支护结构造成较大影响;通过对比,H型钢接头更适用于背景项目。

Taking the underground transportation hub project in the southern area of Pudong Airport as an example,the application effect of different Diaphragm wall joints in foundation pit engineering is analyzed by establishing a numerical model.After comparative analysis,the optimal joint type for the specific project is determined.The result shows that the horizontal displacement of the joint part of the Diaphragm wall increases with the continuous excavation of the foundation pit.The joint displacement reaches the maximum value of 66.3 mm when the foundation pit is excavated to the bottom,and the parts with large horizontal displacement are basically located in the middle and upper parts of the foundation pit during the excavation process.Therefore,it is necessary to carry out early warning work and formulate emergency plans in advance to avoid large-scale leakage.The horizontal displacement of the corresponding part of the Diaphragm wall also varies with different joint types.When the rigid joint is selected,the Diaphragm wall has better ability to transfer stress,stronger bearing capacity and smaller displacement deformation.The trend of horizontal displacement change in the Diaphragm wall with H-shaped steel joint and cross steel plate joint is basically the same duringthe excavation of foundation pit.The value of the support axial force is larger when the horizontal displacement of the joint is significantly reduced at the third concrete support part.Further,the type of Diaphragm wall joint will also have a great impact on the stability of the joint and the supporting structure of the foundation pit.Finally,by comparison,H-shaped steel joints are more suitable for the project under discussion.