Dynamic Response Analysis on Efficacy of CFG-Pile in Different Height Embankment

2011 ◽  
Vol 311-313 ◽  
pp. 145-148
Author(s):  
Jian Xiang
Keyword(s):  
Dynamic Response ◽  
Dynamic Stability ◽  
High Speed ◽  
Stress Ratio ◽  
Dynamic Stress ◽  
Ground Surface ◽  
High Speed Railway ◽  
Dynamic Displacement ◽  
Embankment Height ◽  
Cfg Pile

In order to analyze the effect of embankment height to dynamic stability, Cross-section in the Beijing-Shanghai high-speed railway is chosen and the numerical simulation calculation method is applying. Distributing rules of dynamic displacement and dynamic stress of the subgrade surface and ground surface, 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 into the scope of 10 meters beneath the ground. Moreover, with the increment of embankment height and attenuation of dynamic stress in direct proportion to the depth, the dynamic stress transferring to ground surface decrease and the dynamic displacement of ground surface minish. As a result, the scheme of CFG-pile with 3m scheme is superior to that of 2m 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.

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.

Research on Stress Distribution of CFG Pile-Net Composite Foundation in High-Speed Railway

2013 ◽  
Vol 361-363 ◽  
pp. 1833-1837 ◽  
Author(s):  
Jun Cheng ◽  
Ji Wen Zhang
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Stress Ratio ◽  
Field Tests ◽  
Composite Foundation ◽  
Additional Stress ◽  
High Speed Railway ◽  
Soil Stress ◽  
Gravel Pile ◽  
Cfg Pile

Combined with the field tests of CFG (Cement Fly-ash Gravel) pile-net (geogrid) composite foundation in Danyang Test Section of the Beijing-Shanghai High-speed Railway, the settlement, pile-soil stress ratio and additional stress of composite foundation were analyzed by numerical simulation. It shows that the pile-soil stress ratio of CFG pile-net composite foundation is in the range of 4 to 6. And the reasonable distribution of additional stress in composite foundation is also discussed. The results can provide references for the design of the CFG pile-net composite foundation under embankment in high-speed railway.

scholarly journals Effect of Bridge-Pier Differential Settlement on the Dynamic Response of a High-Speed Railway Train-Track-Bridge System

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaohui Zhang ◽  
Yao Shan ◽  
Xinwen Yang
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Tensile Force ◽  
Differential Settlement ◽  
Bridge Pier ◽  
Vertical Acceleration ◽  
Train Track ◽  
Allowable Limit ◽  
High Speed Railway ◽  
Track Bridge

A model based on the theory of train-track-bridge coupling dynamics is built in the article to investigate how high-speed railway bridge pier differential settlement can affect various railway performance-related criteria. The performance of the model compares favorably with that of a 3D finite element model and train-track-bridge numerical model. The analysis of the study demonstrates that all the dynamic response for a span of 24 m is slightly larger than that for a span of 32 m. The wheel unloading rate increases with pier differential settlement for all of the calculation conditions considered, and its maximum value of 0.695 is well below the allowable limit. Meanwhile, the vertical acceleration increases with pier differential settlement and train speed, respectively, and the values for a pier differential settlement of 10 mm and speed of 350 km/h exceed the maximum allowable limit stipulated in the Chinese standards. On this basis, a speed limit for the exceeding pier differential settlement is determined for comfort consideration. Fasteners that had an initial tensile force due to pier differential settlement experience both compressive and tensile forces as the train passes through and are likely to have a lower service life than those which solely experience compressive forces.

Quick assessment of high-speed railway bridges based on a non-dimensional parameter representation

2017 ◽  
Vol 20 (11) ◽  
pp. 1623-1631 ◽  
Author(s):  
Patrick Salcher ◽  
Christoph Adam
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Response Assessment ◽  
Engineering Practice ◽  
Characteristic Parameters ◽  
Dimensional Parameter ◽  
High Speed Railway ◽  
Railway Bridges ◽  
Parameter Representation ◽  
Bridge Model

The objective of this study is to provide the engineering practice with a tool for simplified dynamic response assessment of high-speed railway bridges in the pre-design phase. To serve this purpose, a non-dimensional representation of the characteristic parameters of the train–bridge interaction problem is described and extended based on a beam bridge model subjected to the static axle loads of the crossing high-speed train. The non-dimensional parameter representation is used to discuss several code-related design issues. It is revealed that in an admitted parameter domain, a code-regulated static assessment of high-speed railway bridges may under-predict the actual dynamic response. Furthermore, the minimum mass of a bridge as a function of the characteristic parameters is presented to comply with the maximum bridge acceleration specified in standards.

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.

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