Case Study on Response Characteristic of Surroundings Induced by a Covered Semi-Top-Down Excavation with Synchronous Construction of the Superstructure and Substructure

Relying on a foundation pit project leveraging the covered semi-top-down method with synchronous construction of the superstructure and substructure in Beijing, the whole process of construction was simulated by using ABAQUS finite-element software. The impact of the whole construction on the surrounding ground, the adjacent building, and the retaining structure were studied, and the influence of the existing building, the strength of diaphragm wall, and the construction process were carried out. As shown from the results, the foundation pit and the existing building are in a safe state during the whole construction process. The ground settlement shows an obvious groove shape. The deformation of the diaphragm wall has obvious spatial effects, which changes from “single peak” to “double peaks”. The maximum horizontal displacement of strata behind the diaphragm wall occurs at a depth of 22.5 m, which is 1.4–2.0 times the top horizontal displacement. The presence of existing buildings reduced the ground settlement between the buildings and the excavation surface. The construction process has little impact on the settlement of adjacent existing buildings, which can be adjusted appropriately.