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Geomechanics and Engineering
  Volume 20, Number 2, January25 2020 , pages 155-164
DOI: https://doi.org/10.12989/gae.2020.20.2.155
 


Mechanical characteristics + differential settlement of CFG pile and cement-soil compacted pile about composite foundation under train load
Xuansheng Cheng, Gongning Liu, Lijun Gong, Xinhai Zhou and Baozhen Shi

 
Abstract
    In recent years, the stability, safety and comfort of trains has received increased attention. The mechanical characteristics and differential settlement of the foundation are the main problems studied in high-speed railway research. The mechanical characteristics and differential settlement of the foundation are greatly affected by the ground treatment. Additionally, the effects of train load and earthquakes have a great impact. The dynamic action of the train will increase the vibration acceleration of the foundation and increase the cumulative deformation, and the earthquake action will affect the stability of the substructure. Earthquakes have an important practical significance for the dynamic analysis of the railway operation stage; therefore, considering the impact of earthquakes on the railway substructure stability has engineering significance. In this paper, finite element model of the CFG (Cement Fly-ash Gravel) pile + cement-soil compacted pile about composite foundation is established, and manual numerical incentive method is selected as the simulation principle. The mechanical characteristics and differential settlement of CFG pile + cement-soil compacted pile about composite foundation under train load are studied. The results show: under the train load, the neutral point of the side friction about CFG pile is located at nearly 7/8 of the pile length; the vertical dynamic stress-time history curves of the cement-soil compacted pile, CFG pile and soil between piles are all regular serrated shape, the vertical dynamic stress of CFG pile changes greatly, but the vertical dynamic stress of cement-soil compacted pile and soil between piles does not change much; the vertical displacement of CFG pile, cement-soil compacted pile and soil between piles change very little.
 
Key Words
    composite foundation; train load; mechanical characteristics; differential settlement
 
Address
Xuansheng Cheng, Gongning Liu, Lijun Gong: 1.) Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province, Lanzhou University of Technology, No. 287, Langongping Road, Qilihe District, Lanzhou, Gansu province, China
2.) Western Engineering Research Center of Disaster Mitigation in Civil Engineering of Ministry of Education, Lanzhou University of Technology, No. 287, Langongping Road, Qilihe District, Lanzhou, Gansu province, China

Xinhai Zhou: Western Engineering Research Center of Disaster Mitigation in Civil Engineering of Ministry of Education, Lanzhou University of Technology, No. 287, Langongping Road, Qilihe District, Lanzhou, Gansu province, China

Baozhen Shi: China Railway 21st Bureau Group Sixth Engineering Co., LTD., No. 921, Beibinhe west road, Anning District, Lanzhou, Gansu province, China
 

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