Study On Soft Foundation Treatment And Settlement Law Of Chengdu Tianfu Airport

Soft soil is widely distributed in the construction area of Chengdu Tianfu Airport.In order to reduce foundation settlement,excavation and filling and foundation treatment projects must be carried out.In this paper,three typical construction sites are selected in dynamic compaction replacement area,CFG pile area,gravel pile + drainage plate area,and the original land subsidence,stratified subsidence and pore water pressure are monitored respectively.The law of subsidence is analyzed and verified by FLAC3 D software simulation.The main conclusions are as follows:1?Foundation settlement of dynamic compaction replacement site mainly occurs during the filling period,accounting for 64.7% of the total settlement of the foundation;settlement of soft soil layer accounts for 53% of the total settlement of the foundation,and the main compression layer of soft soil layer is located in the middle and lower part of the ground,about 2-5 m below the ground,and its settlement accounts for 79% of the total settlement of soft soil layer;drainage effect is remarkable,the stability value of pore water pressure of soft soil at all depths after filling is lower than the initial value.2?61.8% of the total settlement of CFG pile site occurred during the filling period;the main compression layer of foundation settlement is the bearing layer,the vertical deformation of soft soil layer is small and uniform,and the settlement speed is slow.3?The settlement of gravel pile + drainage plate method during construction is 43.1% of the total settlement;the settlement of soft soil layer is only 37% of the settlement of foundation;the bearing layer is the main compression layer,and the settlement value of each depth of soft soil layer is relatively uniform;the drainage condition of soft foundation is greatly improved,and the final pore pressure stability value of each depth is lower than the initial value.4?When the spacing between gravel pile and drainage plate is 1.5m and 1.8m,the variation law of settlement and pore pressure is basically the same.The difference is that when 1.5m pile spacing is adopted,the settlement of foundation is reduced by 13%,the pore pressure is reduced by 11%,which is more suitable for areas with short construction period and high settlement requirement.