地铁深基坑支护结构钢支撑力学参数研究

Mechanical Parameters of Steel Support for Deep Foundation Pit Supporting Structure of Subway

基于岩土数值软件MIDAS GTS NX,建立考虑土体与深基坑相互作用的三维计算模型,并通过模型分析钢支撑预加轴力及刚度等力学参数对深基坑支护结构变形的影响,根据参数分析对钢支撑施工方案进行优化设计。结果表明:预加轴力为设计值的50%~150%,并且钢支撑直径为609 mm、壁厚为14 mm和直径为609 mm、壁厚为16 mm时对基坑支护结构变形和周边地表沉降的限制作用较好;经过优化后基坑地下连续墙的水平位移和周边地表沉降虽有微弱增加,但都处于监测安全范围值以内,同时节省了大量工程成本。

A three-dimensional calculation model of interaction between soil and deep foundation pit was established based on the geotechnical software MIDAS GTS NX. The influence of mechanical parameters such as pre-axial force and stiffness of steel braces on deformation of the deep foundation pit supporting structure was analyzed by the model. The steel supporting construction scheme was designed according to the parameter analysis. The results show that the limitation effect on the deformation of the foundation pit supporting structure and the surrounding ground settlement is better when the preloading force is 50% ～ 150% of the design value and the steel support diameter is 609 mm,thickness is14 mm and diameter is 609 mm,thickness is 16 mm. The horizontal displacement of the diaphragm wall and the surrounding surface subsidence are slightly increased after optimization,but all of them are within the range of monitoring safety,and a lot of engineering cost is saved.