逆作地下室设计中的若干关键问题

Some key problems in design of basements using top-down method

逆作法技术因其施工作业流程与传统的顺作法截然不同,给逆作地下室的设计带来很多新的技术问题,如逆作地下室土压力分布模式与顺作法相比有较大不同,逆作阶段的不同施工顺序和流程对地下室结构及围护结构的内力变形产生显著影响等。结合工程实例在阐述逆作法技术的工艺原理和施工作业流程的基础上,重点针对逆作地下室的竖向支承体系设计、水平支承体系设计与基坑侧向变形控制、围护墙的竖向承载与差异沉降控制、竖向立柱垂直度控制、深层承压水作用下坑底土体抗突涌措施、逆作地下室结构数值分析与施工模拟计算等关键问题进行分析和介绍。

The top-down construction method brings some new technical problems in the design of basements because of its construction process different from that of the normal down-top construction method,for instance,different distributions of the lateral pressure form the down-top construction method,and the significant effect on the stress and displacement of the basements and retaining structures by different construction processes.On the basis of the principal technology and construction process of this new method with the background of practical project examples,some key problems are analyzed and introduced,including the design of vertical and horizontal support systems,the lateral deformation control,the vertical bearing capacity and the differential settlement control of enclosure walls,the verticality control of soldier columns,measures against the sudden welling of foundation pits under the deep confined water as well as the numerical analysis of basements using the top-down method and the staged construction simulation.