Numerical Simulation of Deep Foundation Pit Excavation Support Design in Soft Soil Area

The geological condition of soft soil area is complex, the soil is weak and the groundwater level is high, which is a major hidden danger of construction safety. Combined with a deep excavation project in Shantou, a three-dimensional model of excavation and support of a deep excavation was established by using FLAC3D software, and the influence of excavation of deep excavation in soft soil area on excavation deformation and displacement of surrounding measuring points was simulated under the conditions of diaphragm wall and double-row pile support, so as to reveal the excavation deformation law and surrounding surface deformation law under two working conditions. The results show that with the increase of excavation depth, the lateral displacement of monitoring points on the excavation edge gradually increases; And the measured maximum lateral displacement is under the diaphragm wall, which is about 20mm. After the completion of excavation excavation, the farther the monitoring point of the same section is from the excavation edge in horizontal direction, the smaller its lateral displacement is; Until there is no horizontal influence; Similarly, the farther the vertical direction is from the excavation top, the smaller the lateral displacement is until it decreases to zero. Through the comparison and analysis of monitoring data, the double-row pile supporting structure can better control stratum deformation and ensure the safety of adjacent existing buildings. The research results can provide a good reference for the design and construction of supporting structure in excavation of similar projects in the future.