The Dynamic Analysis of Soft Soil Subgrade in High-Speed Railway Strengthened by PHC Pile

2014 ◽  
Vol 1030-1032 ◽  
pp. 908-911 ◽  
Author(s):  
Zhen Hua Pan ◽  
Kong Ming Yan ◽  
Jin Biao Wu ◽  
Zhe Wang ◽  
Wei Ming Liao
Keyword(s):  
Prestressed Concrete ◽  
High Speed ◽  
Dynamic Stress ◽  
Soft Soil ◽  
Time History ◽  
Composite Foundation ◽  
High Speed Train ◽  
High Speed Railway ◽  
Soft Soil Area ◽  
Soil Area

The combination of PHC pile (prestressed concrete pile) with geogrid to reinforce the foundation has been widely used in high-speed railway, and the response of dynamic stress under the high-speed train is worth studying. By using Midas/GTS NX software to establish a 3-D model of pile-net composite foundation in one section of Hangzhou - Shenzhen line, the influence of pile-net composite foundation generated by high-speed train is studied. Moreover, this paper also studies the distribution and propagation of dynamic stress generated by train load in soft soil area. The results show that the dynamic stress reducing quickly in the embankment structure and the time –history curve of the dynamic stress behaves differently along the depth. With the depth increasing, there is phenomenon of peak superposition in the time-history curve of the vertical dynamic stress. In the meanwhile, the PHC pile is the main structure to propagate and sustain the dynamic stress in soft soil area, and with the tendency of ‘large in the middle, small on both ends’.

scholarly journals Review of research on high-speed railway subgrade settlement in soft soil area

2020 ◽  
Vol 28 (2) ◽  
pp. 129-145 ◽  
Author(s):  
Shunhua Zhou ◽  
Binglong Wang ◽  
Yao Shan
Keyword(s):  
High Speed ◽  
Soft Soil ◽  
High Speed Railway ◽  
Soft Soil Area ◽  
Soil Area

Analysis on Dynamic Transfer Characteristics of Low Geosynthetic-Reinforced Embankments Supported by CFG Piles Subjected to High-Speed Railway

2011 ◽  
Vol 368-373 ◽  
pp. 2575-2580 ◽  
Author(s):  
Long Long Fu ◽  
Quan Mei Gong ◽  
Yang Wang
Keyword(s):  
Field Test ◽  
High Speed ◽  
Dynamic Stress ◽  
Numerical Study ◽  
High Stress ◽  
High Speed Train ◽  
High Speed Railway ◽  
Railway Line ◽  
Transfer Characteristics ◽  
Reinforced Embankments

To investigate the dynamic transfer characteristics of low geosynthetic-reinforced embankments supported by CFG piles under high-speed train load, a numerical study has been conducted through dynamic finite element method on basis of the dynamic field test on a cross-section of Beijing-Shanghai high-speed railway. The comparative analysis on results of numerical study and field test indicated the distribution characteristics of vertical dynamic stress induced by high-speed train load in subgrade soil under railway line. The numerical results also suggested a high stress area in subgrade where vertical dynamic stress is over 1kPa. Conclusions of this work can provide reference for both design and estimation of long-term settlement of low geosynthetic-reinforced embankments supported by CFG piles for high-speed railway.

The Effect of CFG-Pile Caps and Cushion to Stability of Embankment

2011 ◽  
Vol 287-290 ◽  
pp. 797-800
Author(s):  
Zhen Hua Wu ◽  
Jian Yi Yuan
Keyword(s):  
High Speed ◽  
Stress Ratio ◽  
Dynamic Stress ◽  
Vertical Section ◽  
Composite Foundation ◽  
High Speed Railway ◽  
Dynamic Displacement ◽  
Wide Range ◽  
Pile Caps ◽  
Cfg Pile

Subgrade diseases are exposed more and more serious with raising speed of existing railway in wide range. Dynamic numerical simulation had been done to analyze the effect of CFG-pile caps and cushion in composite foundation with CFG-pile in low embankment of Beijing-Shanghai high-speed railway. Distribution rules of dynamic displacement and dynamic stress of the subgrade surface and ground surface on the cross section, attenuation rules of dynamic response and dynamic stress ratio between pile and soil on the vertical section were studied. It shows that the dynamic stress of pile and soil generally attenuates in depth and attenuation of dynamic stress ratio between pile and soil mostly concentrates in the scope of 10m beneath the ground and dynamic stress caused by train load is undertaken by the pile. Moreover the scheme of CFG-pile with no pile caps and rigid cushion scheme is superior to that of pile caps and flexible cushion scheme for enhancing dynamic stability and reducing dynamic displacement and stress in low embankment. It will be instructive to control design and construction for the low embankment in Beijing-Shanghai high-speed railway.

Study on the Effect of Jet Grouting Pile Reinforcing Soft Soil Subgrade

2012 ◽  
Vol 594-597 ◽  
pp. 1420-1428 ◽  
Author(s):  
Gang Yu Liu ◽  
Bing Long Wang
Keyword(s):  
High Speed ◽  
Soft Soil ◽  
Ground Surface ◽  
Horizontal Displacement ◽  
Composite Foundation ◽  
Original Design ◽  
Obvious Effect ◽  
High Speed Railway ◽  
Jet Grouting ◽  
Ground Surface Settlement

Composite foundation is commonly used to control the soft soil subgrade settlement. Considering that post-construction settlement of high speed railway is strictly controlled, it’s supposed to use jet grouting pile to strengthen the existed composite foundation and it’s necessary to analyse the effectiveness. Take a line as an example, analyse embankment settlement regularity of the original design mixing pile reinforcement and jet grouting pile reinforcement, evaluate the effect of the jet grouting pile reinforcement. The results show that the jet grouting pile reinforcement on the basis of original design does not have obvious effect on the embankment surface and ground surface settlement control, but effectively controls horizontal displacement at toe of slope and improves the foundation stability.

Reinforcement Effectiveness Analysis of Road Pile-Plank Structure in Soft Soil Area

2013 ◽  
Vol 482 ◽  
pp. 227-232
Author(s):  
Han Chen ◽  
Si Hui Xu ◽  
Bing Qing Zhang
Keyword(s):  
High Speed ◽  
Soft Soil ◽  
Theoretical Research ◽  
Foundation Treatment ◽  
Treatment Measures ◽  
New Type ◽  
Soft Soil Area ◽  
Strength And Stiffness ◽  
Bridge Foundation ◽  
Soil Area

Pile-plank structure is a new type of structure which is suitable for soft soil area, it has several advantages: higher strength and stiffness, better stability, lower investment, and simple to construction. It is used widely at home and abroad, but the theoretical research lagged behind the project application. This paper take an example of a new constructed road beneath the Yongtaiwen High-speed Railway in soft ground which is adopted pile-plank structure. Firstly, analyze the settlement of pile-plank structure by theoretical calculation and numerical simulation, the result of two methods basically the same. Secondly, analyze the deformation of existing railway bridge foundation by constructing the pile-plank structure. The study of this paper will provide a reference to the foundation treatment measures in soft soil area.

An Analysis on Failure Pattern of CFG Pile-Net Composite Foundation of High-Speed Railway

2012 ◽  
Vol 594-597 ◽  
pp. 1357-1362
Author(s):  
Dan Ping Jiang ◽  
Bing Long Wang
Keyword(s):  
High Speed ◽  
Shear Failure ◽  
Soft Soil ◽  
Composite Foundation ◽  
Failure Pattern ◽  
Lagrangian Analysis ◽  
High Speed Railway ◽  
Foundation Treatment ◽  
Sliding Soil ◽  
Cfg Pile

CFG pile-net composite foundation has the advantages of small post construction settlement and uneven settlement, easy control of construction quality and fast construction speed. It`s widely used in subgrade engineering of high-speed railway. However, in coastal soft soil area, phenomena like breaking pile, collapsed embankment, cracking in embankment surface, undue settlement or convergence appeared in many places where railway CFG pile was improved during the foundation treatment, filling and preloading. Four numerical calculations were performed to investigate the failure pattern of CFG pile-net composite foundation with FLAC3D ( Fast Lagrangian Analysis of Continua, 3 dimensions) software. The paper describes four failure pattern, they are slip circle shear failure, pile tilt failure, roadbed sliding, soil sliding at pile end respectively through the analysis of the embankment and pile displacement as well as embankment deformation.

Prediction of long-term settlements of subway tunnel in the soft soil area

2014 ◽  
Vol 74 (2) ◽  
pp. 1007-1020 ◽  
Author(s):  
Zhen-Dong Cui ◽  
Shi-Xi Ren
Keyword(s):  
Soft Soil ◽  
Subway Tunnel ◽  
Soft Soil Area ◽  
Soil Area
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