敏感环境长条形深基坑内支撑设计及数值分析

为探究长条形深基坑在敏感环境下采取何种内支撑布置型式可以保证紧邻既有建筑及基坑的安全和稳定，以某基坑工程为背景，利用MIDAS GTS NX 对基坑进行考虑土体-结构相互作用的三维上下协同分析，对比了不同支护下的周边建筑控制指标，并且与监测报警值以及现场监测数据进行了对比。结果表明，对撑+角撑型式内支撑较其他类型更为适用；内支撑布置型式对基底隆起的变化形态有显著影响，但对于基底隆起量的影响较小；角撑型和双圆形环梁型内支撑在使用时应增加薄弱点处的刚度。采用对撑+角撑型内支撑既能保证基坑的安全又能较好地控制紧邻既有建筑的变形,对类似工程的设计、施工和变形控制有一定的参考价值。

Design and numerical analysis of internal support for long strip deep foundation pit in sensitive environment

In order to explore what kind of internal support layout can ensure the safety and stability of adjacent existing buildings in the sensitive environment of long strip deep foundation pit, taking an actual project as the background, MIDAS GTS NX was used to analyze the three-dimensional interaction of soil and structure in the foundation pit, and the deformation control indexes of the surrounding buildings and foundation pit under various types of internal support were compared, which were also compared with the monitoring alarm value and field monitoring data. The results show that internal support of the opposite brace and angle brace type is more suitable than other types; the layout of the internal support has a significant effect on the change of the basement uplift, but has little effect on the amount of the uplift; it is suggested to increase the stiffness of the weak point when using the corner brace type support and the double circular ring beam type inner support. The opposite brace and angle brace type internal support can not only ensure the safety of foundation pit, but also better control the deformation of adjacent existing buildings, which has certain reference value for the design, construction and deformation control of similar projects.