Deformation control for a five-story deep excavation

The Hangzhou Hang Lung Plaza features a five-story basement close to a cluster of old, shallow-founded buildings along its 365 m eastern side that are extremely sensitive to deformation. To address the challenges of deformation control, this project employed not only traditional rigid retaining structures of diaphragm walls combined with internal struts but also active protection technologies, such as zoned excavation, cross walls, and axial force servo-controlled concrete struts. The monitoring results indicated that the aforementioned technologies markedly reduced the horizontal deformation of the retaining walls, with a maximum reduction of approximately 43 %, thereby ensuring control of the excavation deformation and facilitating the safety of adjacent buildings. This study validated the effectiveness of zoned excavation, cross walls, and servo-controlled struts under soft soil conditions; however, further research is required to optimize specific parameters and integrate dynamic adjustment algorithms for broader adaptability.