Abstract: In order to resolve the deep foundation excavation in soft soil area, the soil and the supporting structure deformation are usually large. This paper presents a case history of semi-reverse excavation method of deep excavation in saturated soft soils of the Pearl River Delta alluvial plain. The Midas GTS NT 3D modeling results were compared with the construction monitoring data. The following conclusions can be made: (1) after half the semi-reverse excavation in soft soil area, the lateral deformation of supporting structures has a convex in shape, the maximum average in 0.5H~0.6H (H) from excavation depth; (2) The main influence zone of ground settlement and deformation around the excavated area caused by semi-reverse excavation in soft soil area is 0~1.0H. (3) Through the study of this case history, it is shown that the application of the space-time effect theory of semi-inverse method in the deep excavation in saturated soft soils not only ensures the safety of excavation itself and the surrounding environment, but also reduces the construction duration and reduces the construction cost, which provides a reference for the design and construction of deep foundation pit in similar soft soil area.

Key words: Deep Excavation, Saturated Soft Soil Area, Semi-Reverse Method, Numerical Simulation, Effect of Time and Space