对土岩组合基坑混凝土支撑轴力监测的一点思考

Ideas on monitoring the axial force of concrete support in soil-rock composite foundation pit

文章结合之江路工程2号盾构工作井及始发段的土岩组合基坑施工监测实例,阐述了当前基坑施工监测普遍存在的问题,分析和探讨对土岩组合基坑的混凝土支撑轴力监测设计与施工进行合理优化的可能性。在实际的施工监测工作中,不能简单根据单根混凝土支撑轴力平均累计值是否达到或超过设计提供的控制值作为报(预)警的依据。应根据现场施工工况,密切关注支撑平均轴力变化的趋势,同时参考围护结构自身变形位移、基坑周边土体位移等其他监测数据,对支撑轴力的变化进行综合分析判断。笔者建议由设计单位根据基坑工程实际工况和施工监测相关数据,重新进行复核验算,并提出综合安全评估指标,得出可靠结论,达到既安全又经济的工程建设效果。可供本工程其他工作井基坑或类似基坑工程设计、施工监测过程中参考。

In this paper, based on the soil-rock combination foundation pit of Zhijiang Road project, the common problems in the current construction monitoring of the foundation pit were elaborated, and the possibility of reasonable optimization of the axial force monitoring design and construction of the concrete support of the soil-rock combination foundation pit were analyzed and discussed. During the actual monitoring period, the average accumulated value of axial force of single concrete support cannot be used as early-warning index. It is necessary to pay close attention to the change trend of the average axial force of the support according to the site construction conditions, and make a comprehensive analysis and judgment on the change of the axial force by making reference to the deformation of retaining structure and soil displacement around the foundation pit and other monitoring data. It is suggested that according to the real working condition of foundation pit and construction monitoring data, the designer should re-check the calculation, and put forward the comprehensive safety evaluation index, so as to achieve both safe and economic effect. This study can provide a reference in the design and construction monitoring on similar projects.