Method and application of deformation control of excavations in soft ground

The main task of excavations in soft ground is the deformation control, which is closely rated to their safety and environmental impact. With the increase of the buildings and structures in the urban areas, the construction-induced deformation has become the focus of the excavations. The characteristics, mechanism and environmental impact of the deformation caused by each excavation phase are analyzed in a view of the whole-process control. Furthermore, the control methods for the deformation and environmental impact of the excavations are classified into two types, i.e., the control based on the retaining system of the excavations and that based on the protected objects adjacent to them. For the latter type, the active control theory is proposed focusing on the deformation of the protected objects instead of the retaining system. This active targeting technology integrated with the measurement and control for the protected objects is realized by controlling the stress and deformation of the key zone. Finally, the strut-free retaining theory is proposed and a series of strut-free retaining technologies are developed for the excavations in soft ground. The design of strut-free retaining for the excavations with relatively large depth can be realized using these technologies. The theories and applications of the whole-process control, the active control and the strut-free retaining system promote the deformation control of the excavations towards the efficient, intelligent, green and low-carbon aim.