Abstract:
[Objective] Due to the influence of geological conditions, tunnel burial depth, tunnel diameter, and properties of the overlying soil layer, the Peck formula exhibits significant deviations when applied to the shield tunneling construction in water-bearing sandy soil layers in Nanchang area. Therefore, a modification of the formula is necessary. [Method] Based on the field-measured data from a shield tunneling construction in a interval on Nanchang Metro Line 3, along with other measured data, the tunnel burial depth, tunnel radius, and internal friction angle of the overlying soil 3 primary factors that affect land subsidence are comprehensively considered. A calculation formula for land subsidence trough width applicable to Nanchang Metro shield tunneling in water-bearing sandy soils is derived. The range of formation loss rate is determined through inverse calculation using Peck formula. A correction coefficient for maximum subsidence is introduced to perform linear regression modification of Peck formula. [Result & Conclusion] The land subsidence curves predicted by the modified Peck formula closely match the measured subsidence curves, indicating that the formula can effectively predict land subsidence caused by metro shield tunneling construction.