About the author:

China Railway 18th Bureau Group Third Engineering Co., Ltd., Zhuozhou, Hebei 072750, China

Abstract:

The settlement of ground raft foundations caused by shield tunnel construction is studied basedon numerical simulation and multiple regression. A regression model was established and verified bytaking Nanchang Metro Line 4 as an example, considering factors such as excavation diameter, tunneldepth, foundation⁃tunnel spacing, foundation roof pressure, soil elastic modulus, etc. The resultsindicate that the raft settlement decreases with the increase in spacing, buried depth, and soil modulusand increases with the increase in excavation diameter and roof pressure. When the spacing is 23m, thesettlement is reduced by 83. 5% compared with the direct undercrossing. The settlement is about 5.75mmwhen the excavation diameter is 6.5m. The settlement is reduced by 38. 4%when the buried depthincreases from 15m to 21m. When the soil modulus is reduced to 0.5E, the settlement surges by 73%.And when the soil modulus is increased to 1.5E, the settlement is reduced by 28%.