Performance of a Deep Excavation Irregular Supporting Structure Subjected to Asymmetric Loading

Because of the extreme terrain limitations and heavy traffic in congested urban areas, the supporting structures for deep excavations often undergo an asymmetric loading condition at two sides. This article reports the results of an investigation based on detailed numerical modeling of the supporting scheme and mechanical performance of a deep excavation of a metro station having different elevations at two sides. The two proposed types of design schemes for support and excavation were discussed and analyzed to evaluate the suitability of using regular or irregular supporting structures. The mechanical performance of the adopted supporting scheme was then evaluated using three-dimensional numerical analysis and verified via field observations. The results show that the irregular supporting structure functions satisfactorily when subjected to asymmetric loading, and it can also realize semicovered excavation in narrow and congested downtown areas to effectively solve the problem of traffic. The solution presented in this study can provide valuable references for the design of urban deep excavations with an asymmetric side elevation.