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.

Research on the Large Size Loading Plate Test of Underwater Sand Compaction Pile Composite Foundation

2015 ◽  
Vol 744-746 ◽  
pp. 574-578
Author(s):  
Jin Fang Hou ◽  
Jian Yu ◽  
Xin Wei Xu
Keyword(s):  
Bearing Capacity ◽  
Stress Ratio ◽  
Soft Soil ◽  
Deformation Modulus ◽  
Load Test ◽  
Composite Foundation ◽  
Plate Test ◽  
Loading Mode ◽  
Large Size ◽  
Soil Stress

Large size loading plate test for sand compaction pile composite foundations with the replacement ratio being up to 60% was carried out to study the deformation and bearing capacity of the sand compaction pile composite foundation. The test was carried out for 53 days with anchor pile, square loading with the side length of 5.4m, 15m-deep water and twice circulation loading mode. The compression deformation, pile-soil stress ratio and deformation modulus of the sand compaction pile composite foundation was analyzed through load test. Test results indicated that, the ultimate bearing capacity of the sand compaction pile composite foundation in this test was larger than 340kPa; sand compaction pile had a drainage consolidation effect on the soft soil between piles; under the load-keeping condition, sand compaction pile composite foundation would also has settlement; pile-soil stress ratio was 6.3 and deformation modulus was about 8kPa. The success of the test may provide experience and reference for load test of underwater sand compaction pile composite foundation carried out at open sea.

Finite Element Analysis of Cushion Thickness and Ultimate Bearing Capacity of Lime Soil Pile Composite Foundation

2012 ◽  
Vol 594-597 ◽  
pp. 565-569
Author(s):  
Zi Sen Wei ◽  
Yong Mou Zhang ◽  
Dong Hui Peng
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Stress Ratio ◽  
Shear Failure ◽  
Ultimate Bearing Capacity ◽  
Load Test ◽  
Composite Foundation ◽  
Static Load Test ◽  
Rate Of Increase ◽  
Soil Stress

The static load test of composite foundation was simulated by using the nonlinear finite element programs, and the changes of the pile-soil stress ratio and the pile and soil settlements as well as the plastic deformation of composite foundation were analyzed. The simulation results show that: the cushion of flexible pile composite foundation can effectively regulate the pile-soil stress ratio and make the bearing capacity of the lime soil pile and the soil between piles give full play at the same time. The cushion has a distinct role in reducing the pile settlements, however, has little effect in reducing the soil settlements. The reasonable cushion thickness is about 300mm. The composite foundation will emerge local shear failure when it reaches the ultimate bearing capacity. Reducing the pile spacing can increase the ultimate bearing capacity, and the rate of increase shows a gradually increasing trend.

scholarly journals Settlement Analysis of Saturated Tailings Dam Treated by CFG Pile Composite Foundation

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Jinxing Lai ◽  
Houquan Liu ◽  
Junling Qiu ◽  
Jianxun Chen
Keyword(s):  
Model Test ◽  
Deformation Modulus ◽  
Composite Foundation ◽  
Laboratory Model ◽  
Tailings Dam ◽  
Foundation Treatment ◽  
Building Foundation ◽  
Cfg Pile Composite Foundation ◽  
Laboratory Model Test ◽  
Cfg Pile

Cement fly ash gravel (CFG) pile composite foundation is an effective and economic foundation treatment approach, which is significant to building foundation, subgrade construction, and so forth. The present paper aims at investigating the settlement behaviors of saturated tailings dam soft ground under CFG pile composite foundation treatment, in which FEM and laboratory model test were utilized. The proposed findings demonstrate that CFG pile treatment is effective in reinforcing saturated tailings dam and loading has little influence on settlement of soil between piles. The variation of soil between piles settlement in FEM has a good agreement with the laboratory model test. Additionally, the cushion deformation modulus has a small effect on the composite foundation settlement, although the cushion thickness will generate certain influence on the settlement distribution of the composite foundation.

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.

Study and Analysis on Pile-Soil Stress Ratio of the Composite Foundation of Cement-Soil Mixing Pile under Flexible Foundation

2011 ◽  
Vol 335-336 ◽  
pp. 1145-1150
Author(s):  
Xiao Rong Yang ◽  
Lei Yu Zhang ◽  
Hai Chao Li ◽  
Li Ying Dong
Keyword(s):  
Stress Ratio ◽  
Soft Soil ◽  
Composite Foundation ◽  
Soil Mixing ◽  
Soil Stress ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Flexible Foundation ◽  
Cement Soil ◽  
Friction Pile

In order to analyze the characteristics of pile-soil stress ratio of the composite foundation of cement-soil mixing pile under flexible foundation, this paper points out the displacement mode of friction pile; According to the deformation characteristic of friction pile, ascertain the neutral point of composite foundation. And this paper also derives the exact formula about length-stress ratio which addresses the problem of soft soil foundation according to the deformation co-ordination conditions of the pile composite foundation. The calculation of actual example proves that the formula about pile-soil stress ratio is in accordance with actual measurement number. The pile-soil stress ratio which addresses the problem of soft soil foundation is generally between 2~4. If other conditions keep invariable, pile-soil stress ratio become big when cushion modulus become big. Cushion modulus effect the length-stress ratio greatly.

Application of LS-SVM to Prediction of Bearing Capacity of Cement-Flyash-Gravel Pile Composite Foundation

2013 ◽  
Vol 438-439 ◽  
pp. 1399-1403
Author(s):  
Wei Ding ◽  
Qing Liu ◽  
Kang Kang Sun ◽  
Feng Tao Sui
Keyword(s):  
Bearing Capacity ◽  
Great Influence ◽  
Composite Foundation ◽  
Learning Ability ◽  
Support Vector ◽  
Data Prediction ◽  
Svm Model ◽  
Cfg Pile Composite Foundation ◽  
Gravel Pile ◽  
Cfg Pile

There are a lot of factors that influence the bearing capacity of composite foundation, and the relationship between them is complex and nonlinear. Based on study of main factors that have great influence on bearing capacity of cement-flyash-gravel (CFG) pile composite foundation, the least squares support vector machine (LS-SVM) model of bearing capacity of composite foundation was established. The results show that the model has excellent learning ability and generalization and can provide accurate data prediction only with fewer observed sample. It is proved that the new method is a promising method for the determination of bearing capacity of CFG pile and other rigid piles composite foundation.

Analysis on Bearing Capacity of CFG Pile Composite Foundation in Baotou

2013 ◽  
Vol 353-356 ◽  
pp. 337-340
Author(s):  
Ying Hao Wang ◽  
Yu Qin Feng ◽  
Shuo Li
Keyword(s):  
Bearing Capacity ◽  
Sandy Soil ◽  
Inner Mongolia ◽  
Composite Foundation ◽  
Engineering Project ◽  
Silty Soil ◽  
Practical Engineering ◽  
Soil Foundation ◽  
Cfg Pile Composite Foundation ◽  
Cfg Pile

By uniting composite foundation with CFG pile composite foundation for a practical engineering project in Baotou, the bearing capacity of CFG pile in sandy soil and silty soil foundation were analyzed. The conclusion can be applied to the similar projects in the region of Inner Mongolia.

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.

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