Analysis Of The Displacement And Bending Moments Of Supporting Structures In Foundation Excavation

With the continuous development of city construction in our country, the construction of massive rail transport is increasing. The scale of the tunnel excavation projects is becoming larger, the excavation is becoming deeper, and the risks of these projects are becoming higher. In order to ensure the safety of the supporting structure, it is becoming a growingly valuable project to study the displacement deformation of different supporting structures as well as the patterns and characteristics of its bending moments. Based on the cut-cover tunnel project in Shouyi Square of Wuhan, this paper aims to focus on cantilever piles and piles +steel supporting from the following aspects:1. The paper summarizes and analyzes the methods and basic principles of calculating the bending moments of the supporting structure based on measured data. It also points out the key question is how to obtain the deformation curvature of the supporting structure. Measured data includes reinforcement stresses and inclinometer curve. Since it is impossible to put plenty of stress gauges within the supporting structures, the method of calculating the bending moments based on the measured reinforcement stresses is unrealistic. Therefore, the study will mainly rely on inclinometer curve.2. Based on the studies of P.S.K.Ooi and T.L.Ramsey, the paper adopts the method of piecewise cubic curve fitting to simulate the deformation and calculate the bending moments. Through an in-depth analysis of the results and real-time estimation of the safety of the supporting structures during the complicated process of excavation, the paper puts forward a convenient and practical method.3. Based on former studies, the paper summarizes the theories and methods of analyzing supporting structures in the deep foundation excavation and puts forward systematic and reasonable methods of calculating the displacement and stresses of supporting structures. For instance, the incremental calculation method can be used to model the construction process.4. Through an integrative analysis of theories and methods of analyzing supporting structures in the deep foundation excavation, the paper adopts the analytical method and numerical simulation and calculates the deformation and stress of the cantilever piles supports and piles +steel supports in the cut-cover tunnel project in Shouyi Square of Wuhan. Meanwhile, the paper conducts a comparative analysis of the results and concludes the pattern and characteristics of the displacement deformation and bending moments of the two typical supporting structures in deep foundation excavation.