软土深基坑预应力混凝土伺服支撑设计与实践

Design and Practice of Prestressed Concrete Servo Support for Deep Foundation Pit in Soft Soil

结合上海市虹口区某深基坑工程案例,介绍了预应力混凝土伺服支撑技术的应用情况。实践表明,混凝土支撑施加预应力可采用双圈梁结合支敦及千斤顶系统,该系统能保证混凝土支撑体系传力明确且变形协调;混凝土支撑采用预应力措施后,可以有效消除支撑自身的变形,控制支挡结构的变形,进而减小基坑周边保护对象的变形;预应力混凝土支撑实施过程应加强动态监测,关注相邻支撑加载时的联动影响,并根据监测结果动态调整支撑力。

Combined with a deep foundation pit in Hongkou District of Shanghai,the application of a prestressed servo control system in deep foundation pit concrete support is introduced.The practical case shows that:The double ring beam combined with the support and jack system can effectively ensure the clear force transmission and deformation coordination of the concrete support sys-tem;The servo control technology of prestressed concrete support can significantly eliminate the deformation of the concrete support system,and can effectively control the displacement of foundation pit support structure,to reduce the impact on sensitive protection ob-jects around foundation pit;Dynamic monitoring should be strengthened during the implementation of prestressed concrete support and attention should be paid to the interaction and influence of different support loads,the prestress should be dynamically adjusted accord-ing to the monitoring results.