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.

Numerical Simulation on the Reinforcing Effect of New CFG Pile-Board Structure Composite Foundation

2011 ◽  
Vol 243-249 ◽  
pp. 2415-2418
Author(s):  
Ding Bang Zhang
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Composite Foundation ◽  
Board Structure ◽  
Treatment Technique ◽  
High Speed Railway ◽  
Concrete Pile ◽  
Soil Stress ◽  
Deformation Compatibility ◽  
Cfg Pile

The new CFG pile-board structure composite foundation is a ground treatment technique based on CFG pile foundation and pile-board structure composite foundation. It can make full use of the load distributing function of board, the bearing capacity and the deformation compatibility of soil between piles, by taking advantage of the pile-platform-soil interaction. A part of soft ground in a high-speed railway was taken as the engineering background and study object. The settlement controlling effect of common CFG pile ground and new CFG pile-board structure composite foundation were analyzed by finite element numerical method, and various factors to the effect on settlement-controlling were discussed. Pile-soil stress ratio of CFG pile and reinforced concrete pile were studied. Some useful conclusions of the numerical simulation of the new CFG pile-board structure composite foundation were obtained.

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.

Studies on the Residual Settlement of CFG Pile Composite Foundation of the Wuhan-Guangzhou High Speed Railway

2012 ◽  
Vol 178-181 ◽  
pp. 1590-1595
Author(s):  
Feng Zhang ◽  
Zhao Yi Xu ◽  
Zhi Yi Li
Keyword(s):  
High Speed ◽  
Soil Layer ◽  
Composite Foundation ◽  
High Speed Railway ◽  
Actual Observation ◽  
Permanent Load ◽  
Cfg Pile Composite Foundation ◽  
Gravel Pile ◽  
Pile Length ◽  
Cfg Pile

Wuhan-Guangzhou passenger special line is the most important backbone of China high speed railway net. The line span is 968 km, among of them; roadbed is 388 km, occupied 40.1% of the total line. Due to the rigorous residual settlement of the roadbed, the CFG (Cement Flayash Gravel) pile is used as the composite foundation to enforce the intensity of roadbed and reduce the post-settlement. The paper studies on CFG pile composite foundation at the Wuhan experimental section, using the finite element numerical simulate the interaction of the pile and pile surrounding soil under the permanent load conditions. The results show that the stimulation model has the more accordance with the actual observation results. The residual settlement comes from the soil layer is bigger than the pile length.

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.

Composite Foundation on Bearing Characteristics and Simulation Analysis CFG Pile for the High Speed Railway

2011 ◽  
Vol 71-78 ◽  
pp. 3827-3831
Author(s):  
A Lan Jiang ◽  
Mei Xia Wang
Keyword(s):  
High Speed ◽  
Simulation Analysis ◽  
Coupling Effect ◽  
Rapid Development ◽  
Composite Foundation ◽  
Treatment Technology ◽  
High Speed Railway ◽  
Cfg Pile Composite Foundation ◽  
Sand And Gravel ◽  
Cfg Pile

With the rapid development of high-speed railway in soft foundation, foundation treatment technology has become mature, the most outstanding is CFG pile composite foundation technique. CFG pile composite foundation is made of cement fly ash gravel pile(CFG pile), pile of soil and sandstone , between sand and gravel several problems such as the medium material composition together constitute layer. It has high bearing of capacity, convenient, low costing, strong adaptability and quality control easier.So it is widely applied and promoted. Under static and dynamic loads, the relations of the high-speed railway CFG pile composite foundation is very complex. In order to further understand the intensity of pile-net structure subgrade stability and deformation, pile , requirements of the high-speed railway roadbed ,it needs to do pile-net structure parameter sensitivity analysis. According to high-speed railway CFG pile composite foundation , the numerical analysis can well solve the coupling effect of piles and soil. So, this paper adopts FLAC3D finite difference software is simulated and analyzed.

scholarly journals Stress Analysis of CFG Pile Composite Foundation in Consolidating Saturated Mine Tailings Dam

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Jinxing Lai ◽  
Houquan Liu ◽  
Junling Qiu ◽  
Haobo Fan ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Mine Tailings ◽  
Stress Ratio ◽  
Deformation Modulus ◽  
Earth Pressure ◽  
Composite Foundation ◽  
Three Dimensions ◽  
Laboratory Model ◽  
Soil Stress ◽  
Cfg Pile

Cement fly-ash gravel (CFG) pile is a widely used ground reinforcement technique. This paper aims to address the mechanical characteristics of CFG composite foundation in consolidating saturated mine tailings (MTs) dam. The field static load tests were employed to explore the bearing capacity of the CFG composite foundation, and finite element (FE) models in three dimensions validated through comparison with experimental results were used to discuss the pile-soil stress distribution and pile-soil stress ratio of the CFG composite foundation. The results indicate that the distribution of earth pressure and pile stress is relatively homogeneous and stable over depth and load, while the development of CFG composite foundation bearing capacity is insufficient, in which the developed bearing capacity of CFG piles is less than 50% of its characteristic value. Additionally, compared with the laboratory model test results, the pile-soil stress ratio decreases with the increasing of the load in FEM results proved to better conform to the actual engineering conditions. Furthermore, the deformation modulus and thickness of cushion exert significant influence on pile-soil stress ratio and integral bearing capacity of CFG composite foundation.

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