地下变电站深基坑工程的变形控制

Deformation Controlling of Deep Foundation Excavation for Underground Substation

地下变电站基坑由于周边环境复杂,开挖深度大,基坑支护结构设计时的决定因素是变形控制。菜市口220 k V变电站深基坑工程深度超过30 m,是北京地区较深的基坑之一。本文通过该工程案例,阐述以变形控制为原则的基坑支护设计方法。同时运用FLAC3D的数值模拟进行应力应变分析。应用上述两种方法预测支护结构变形和周围土体位移场,进行详细的基坑支护方案设计,同时施工过程中采取变形控制措施。理论计算的支护结构变形、周边土体的位移与实际监测数据相吻合。

Because the surrounding environment of underground substation is complex, the excavation depth is large. the decisive factor in the design of the retaining and protection structure for the excavation is the deformation controlling. Excavation engineering of Caishikou 220 k V substation is deeper than 30 m, which is one of the most deep excavation in Beijing area. In this paper, through the engineering case, this paper expounds the design method of retaining and protection for excavation based on the principle of deformation control. At the same time, the stress and strain analysis is performed by using the numerical simulation of FLAC3 D. Using these two methods to predict the deformation of retaining and protection structure and the surrounding soil displacement field, the design of retaining and protection structure for the excavation is carried out in detail, and the deformation control measures are taken during the construction process. Theoretical calculation of deformation for the retaining and protection structure and the displacement of the surrounding soil are consistent with the actual monitoring data.