多环梁内撑在软土深基坑中的变形分析

DEFORMATION ANALYSIS OF MULTI-RING BEAMS SUPPORTED IN SOFT SOIL DEEPFOUNDATION PIT

随着城市建设的发展,深基坑工程越来越多,文中以宁波轨道交通5号线一期前殷停车场基坑工程为例,通过实测数据对多环梁内撑在软土深基坑应用中变形特征进行分析并得出相应结论。结果表明围护结构侧向最大位移一般出现在基坑中部,且整体呈现“鼓肚型”变化趋势;在环梁结构中,内侧环梁的直径较小,因此其刚度较大,拱效应也更加明显。在负载传递的过程中,内侧环梁承担了更大的支护力分配;围护结构最大侧向位移随着开挖深度的增加不断增大并向下移动。因此,在基坑设计和施工中可以利用“坑角效应”,通过合理设计基坑角部围护结构,降低其强度要求。此外,在基坑开挖过程中,应加强对支护结构变形和受力较大部位的监测,提前采取适当的防护措施。文中内容可为类似项目设计施工提供一定参考价值。

Deep foundation pit projects prevail with the development of urban construction.Taking the foundation pit project of Ningbo Rail Transit Line 5 as the case,the paper analyzes the deformation characteristics of multi-ring beam inner support in the application of soft soil deep foundation pit through the measured data.The results show that the maximum lateral displacement of the enclosure structure generally occurs in the middle of the foundation pit,and the overall change trend is bulge type.In the ring beam structure,the diameter of the inner ring beam is smaller,so its stiffness is larger,and the arch effect is more obvious.In the process of load transfer,the inner ring beam bears more support force distribution.The maximum lateral displacement of the enclosure structure increases and moves downward with the increase of excavation depth.Therefore,the pit angle effect can be used in the design and con⁃struction of foundation pit,and the strength requirement can be reduced by reasonably designing the corner enclosure structure of foundation pit.In addition,in the process of foundation pit excavation,we should strengthen the monitor⁃ing of the deformation and stress of the supporting structure,and take appropriate protective measures in advance.The content of this paper may provide the reference value for the design and construction of similar projects.