Study On Settlement Characteristics Of Piled Siab Structure By Train Load

As a new structure form,the piled slab structure has high strength,rigidity,cost performance,stability and durability widely used in high speed railway soft foundation reinforcement.Therefore analyzing the influence of piled slab structure on foundation settlement under train load is very important.This paperrefers to Regional Natural Science Foundation of project study on the long-term deformation mechanism of the Red River Basin subgrade foundation under the dynamic load of the high-speed trains.Based on Wuhan-Guangzhou high speed railway using numerical analysis software FLAC3D,the settlement and stress of the bearing plate,pile and soil around piles are analyzed by the static load and the dynamic load at 160km/h,250km/h and 300km/h respectively.The influence factors on the settlement(pile modulus,pile length and pile longitudinal spacing)are compared to determine the optimal value.The main contents and conclusions are listed as follows:(1)The settlement and stress of the bearing plate,pile and soil around piles are calculated by static load at 160km/h,250km/h and 300km/h respectively,and the results are compared and analyzed.According to the calculated results:the settlement of the load-bearing plate increases with the increase of the vehicle speed,but the increase is getting smaller and smaller;the settlement of the pile is larger than that of the soil around piles;the pile end has a great influence on the soil 1m above.(2)The settlement characteristics of the piled slab structure subgrade soil and different structures under the simplified dynamic load and the vehicle speed is 160km/h,250km/h and300km/h.With the increase of speed,the compression of the pile increases;the stress of the soil around piles increases with the increase of depth and the influence of the speed on the soil stress is very mild;the stress of soil between piles increases with the increase of speed.The pile end has a great influence on the soil 4m above under the dynamic train load.(3)Through the speed of 300km/h,the influences of pile modulus,pile length and pile spacing on settlement are analyzed.The optimal modulus(2.6×10~4MPa),the optimal pile length(16m~20m)and the optimal pile longitudinal spacing(7.5m)are obtained which can provide reference for related design and construction.