Abstract: The rapid development of urban infrastructure has led to the numerous foundation pits close to highways, posing new challenges for deformation control of both the foundation pits and the adjacent expressways. To ensure the safety of expressways adjacent to deep foundation pits, this studyuses the finite element method to establish a three-dimensional numerical simulation model considering the vehicle load based on the project overview, construction methods, and reinforcement measures of a deep foundation near an expressway. Then the displacement of the highway pavement, the displacement and the internal force of the supporting structure during and after the excavation were systematically analyzed. The results reveal that there is a phenomenon of uplift on both sides of the middle settlement. The horizontal displacement of the pavement and supporting structure towards the direction of the foundation pit is found, and the supporting structure present a “float up” as a whole. The middle beams of the supporting structures are under compression, while the side beams are under tension, with the compressive forces significantly exceeding the tensile forces. Increasing the supporting density can effectively reduce the displacement of both the pavement and the supporting structure.

Key words: expressway, deep foundation pit, construction method, supporting structure, finite element simulation