Comparative Analysis on Neutral Point Distribution in Rigid Pile Composite Foundation on Collapsible Loess in High Speed Railway

Abstract:

To research and analyze the neutral point distribution of rigid pile composite foundation on collapsible loess ground in high speed railway, the centrifuge model tests are used to imitate pile raft composite foundation and pile net composite foundation in different pile spacing based on the experimental study at home and abroad. The research results show that the movement of negative skin friction and the position of neutral point which is drop conspicuously with larger pile spacing are a continuous changing process in composite foundation. In the pile spacing 2D,4D,6D of pile raft composite foundation, the stable range of neutral point position are 0.25(the pile length ratio), 0.59,0.63 separately in post-construction stage. In the pile spacing 2D(no pile-cap),4D(no pile-cap),4D(pile-cap),6D(pile-cap) of pile net composite foundation, the stable range of neutral point position are 0.37to0.43(the pile length ratio),0.50,0.80,0.81separately in post-construction stage. The pile-cap setting has more influence on Neutral point distribution. Suggestions are given that the waterproof and drainage measures in foundation must be considered when setting up composite foundation on collapsible loess.

• Periodical: Applied Mechanics and Materials (Volumes 90-93)
• Pages: 471-476
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.90-93.471
• Online since: September 2011
• Authors: Chang Dan Wang, Hui Su, Chun Hua Zou
• Keywords: Centrifuge Model Test, Collapsible Loess, Composite Foundation, Neutral Point, Rigid Pile, Subgrade Engineering

References

[1] B.L Wang. High-speed railway subgrade engineering. Beijing: China Railway Publishing House. (2007). In Chinese

[2] X.N Gong. Theory and engineering application of composite foundation. Beijing: China Building Industry Press. (2002). In Chines

[3] C.D Wang , B.L Wang , X Wang et al. Analysis on Settlement Controlling Effect in Pile-net Composite Foundation on Collapsible Loess by Centrifugal Model Tests. Journal of the China Railway Society, Vol.33(4) (2011)p: 84-92 In Chines

[4] X.F HUANG, Z.H CHEN , S HA, etal. Large area field immersion tests on characteristics of deformation of self weight collapse loess under overburden pressure. Chinese Journal of Geotechnical Engineering.Vol.28（3）(2006).p:383-389 In Chines

[5] HABIBAGAHI G,MOKHBERI M.A hyperbolic model for volume change behavior of collapsible soils.Can Geotech JVol.35. (1998)p:264–272.

DOI: 10.1139/t97-089

[6] Y.Q ZHU , Z.H CHEN . A new method of studying collapsibility of loess. Chinese Journal of Geotechnical Engineering..Vol:4 (2008)p: 524-528 In Chines

[7] Y.S LUO , D.Y XIE , S.J SHAO，etal. Variation characteristics of soil structure of unsaturated loess. Jour. of Northwest Sci-Tech Univ. of Agri. and For.(Nat. Sci. Ed.) .Vol:8(2004)p:114-117 In Chines

[8] C.D WANG, X WANG, S.H ZHOU, etal. Centrifuge model tests on self-weight collapsible loess and negative skin friction of pile foundation. Chinese Journal of Geotechnical Engineering.Vol:s1.(2010)p:775-779 In Chines

[9] Y.J ZENG, W.M ZHANG. Reviews of state-of-art of modeling simulation on pile foundations. Rock and Soil Mechanics,Vol:10.(2003)p:674-680 In Chines

[10] Z.Q HUANG, S.J WANG. A Study of application of centrifugal model testing in China. Chinese Journal of Rock Mechanics and Engineering.Vol:17(2) (1998)p:199-203. In Chines

[11] C.D WANG. The Research on the Settlement Controlling and Geotechnical Centrifuge Tests of Piled Embankment in Collapsible Loess Ground of High-speed Railway. Lanzhou：Lanzhou Jiaotong University, (2008) In Chines

[12] TAYLOR R N. Geotechnical Centrifuge Technology [M].Blackie Academic & Professional(1995).

[13] C.G BAO, X.B RAO. Principle of the Geotechnical Centrifuge Model Test [J]. Journal of Yangtze River Scientific Research Institute.Vol15.(1998)(2)p:2–7 In Chines