Design and monitoring of bracings for a deep foundation pit in Lanzhou

Taking a deep foundation pit in Miaotanzi, Lanzhou as are example, the design highlights of pile-prestressed anchor in deep excavations are discussed, and real-time monitoring of pile displacements of top and piles during the process of construction is carried out. By using the finite element software PLAXIS, HSS soil constitutive model is adopted for numerical verification. The monitoring and numerical simulation analysis show that supported by the pile-prestressed anchor, excavation of deep foundation pit has little effect on the adjacent buildings. This kind of bracing can effectively limit the lateral displacement of deep foundation pit. The numerical results agree with the monitoring data. The HSS soil constitutive model is more suitable for numerical analysis of foundations containing pebbles and mudstone geological conditions.