Abstract：The diaphragm wall has been used in many geological conditions for the deep foundation pit enclosure structure. But study on deformation of diaphragm wall in round gravel strata is very few. The paper is based on the Nanning metro line 2 Su Lu foundation pit, and make numerical simulation analysis about the deformation of deep foundation pit standard section and shield-construction origination shaft section in round gravel strata by Midas/GTS. In other sides, the paper makes theoretical analysis by monitoring data. The result shows that the diaphragm wall enclosure structure works well, the lateral displacement is small and the whole deformation is similar to the bow. Because the shield-construction origination shaft section lateral displacement is larger than others which is wider than other parts. Therefore, the excavation width should be controlled. Finally, the model calculation results and monitoring results indicate that the deformation of diaphragm wall lateral displacement increases fastest at 0.7H. So the support should be set at 0.7H for the deep foundation pit in round gravel strata.
