Analyzing on Bearing Performance Influence Factors of Step Cross-Section Pipe Pile

2015 ◽  
Vol 744-746 ◽  
pp. 432-436
Author(s):  
Jie Liu ◽  
Fu An Huang ◽  
Qing Guang Yang ◽  
Bin Cui
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
Soft Soil ◽  
Influence Factors ◽  
Single Pile ◽  
Variable Cross ◽  
Obvious Effect ◽  
Pipe Pile ◽  
Geological Conditions ◽  
Hard Soil

In order to improve the bearing behavior and the bearing capacity of single pipe pile, the technology of step cross-section pipe-pile is proposed.Based on FLAC3D, the finite difference model of the pile-soil interaction established,bearing behaviors of step cross-section pipe pile and unimate cross-section pipe pile is studied comparatively and bearing performance influence factors of step cross-section pipe pile is discussed.The results show that the bearing capacity of step cross-section pipe pile is much higher than unimate cross-section pipe pile in the same geological conditions and material dosage. For layered foundation, the bearing capacity of single pile may be improved by setting variable cross-section pile joint in relatively hard soil. But the depth of joint embedded in hard soil has little influence on bearing capacity of single pile.There is an obvious effect on increasing capacity of single pile by improving soil properties of soft soil surrounding pile.

SVM Model Based on the Influencing Factors Evaluation and Prediction of Ultimate Bearing Capacity of Statically-Pressured Pipe Pile

2011 ◽  
Vol 243-249 ◽  
pp. 2534-2542
Author(s):  
Jian Bin Zhao ◽  
Chao Xu ◽  
Yong Qiang Shi ◽  
Xiao Yan Feng
Keyword(s):  
Bearing Capacity ◽  
Influencing Factors ◽  
Ultimate Bearing Capacity ◽  
Support Vector ◽  
Single Pile ◽  
Pipe Pile ◽  
Model Based ◽  
Svm Model ◽  
Geological Conditions ◽  
Importance Analysis

The prediction accuracy of vertical ultimate bearing capacity of statically-pressured pipe pile is difficult to ensure with traditional methods, because it is influenced by comprehensive factors, such as pile body, soil around pile and construction conditions. In this paper, a support vector machine (SVM) model based on the influencing factors importance evaluation was established to predict the vertical ultimate bearing capacity of single pile. This method would consider grey relational analysis and variable projection importance analysis as the attribute preprocessor facilities, which could determine the vertical bearing character in typical geological conditions through the analysis results of these two methods. Then, the SVM model was established with the main factors influencing ultimate bearing capacity as input to predict ultimate bearing capacity of single pile. The results showed that this method would have better precision of prediction, and the established model would have better generalization ability, which would open up a new way for the theoretical analysis of bearing characters of statically-pressured pipe pile and provide references for future relevant research.

Field Test of DX Pile Group

2011 ◽  
Vol 243-249 ◽  
pp. 2451-2455
Author(s):  
Song Tao Tang ◽  
Li Hong Chen
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
Pile Group ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Test Results ◽  
The Mean ◽  
Engineering Practices ◽  
Pile Length

DX pile is a newly developed variable cross-section pile. Compared to conventional straight pile, it has distinct advantages on bearing capacity and settlement control. However, the bearing mechanism and characteristics of settlement, especially on group DX piles, are not clear. This paper illustrated and analyzed the bearing capacity and settlement characteristics of single DX pile and group DX piles according to the test results of in-situ model test. Special attention was paid on single and group DX pile comparison under same circumstances, at the mean while, compared the single DX pile and conventional pile with the same pile length and diameter, and with the same bearing capacity. The conclusions from the test results provided theoretical references for the design of the DX piles in engineering practices.

Time Effect Research of Prestressed Pipe Pile Based on High Strain Dynamic Test

2012 ◽  
Vol 256-259 ◽  
pp. 531-534
Author(s):  
Jia Tao Wang ◽  
Hong Li Zhao
Keyword(s):  
Bearing Capacity ◽  
High Strain ◽  
Dynamic Test ◽  
Ultimate Bearing Capacity ◽  
Time Effect ◽  
Load Test ◽  
Single Pile ◽  
Dead Load ◽  
Pipe Pile ◽  
Effect Mechanism

More detailed information about the bearing capacity and integrity of the pile can be obtained by high strain dynamic test than by dead-load test [1]. Engineering examples show that the bearing capacity of the prestressed pipe pile gradually increase with the growth of the resting time, and the ultimate bearing capacity of the pile can reach up to 2 times more than the initial bearing capacity. Through the study of the time effect mechanism, it is found that the increment of ultimate bearing capacity of the single pile is mainly caused by side soil resistance. The end resistance has little influence on the time effect of bearing capacity of pile.

Model Tests Research on Extruding Soil Caused by Close-Mouth Step Cross-Section Pipe Pile

2015 ◽  
Vol 744-746 ◽  
pp. 531-535
Author(s):  
Qing Guang Yang ◽  
Jie Tian ◽  
Jie Liu ◽  
Ya Hui Wang
Keyword(s):  
Cross Section ◽  
Soil Surface ◽  
Average Diameter ◽  
Horizontal Displacement ◽  
Penetration Resistance ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Pipe Pile ◽  
Uniform Cross Section ◽  
Pile Model

To study extruding soil caused of close-mouth step cross-section pipe Pile, model experimentals of five static piling tests with two constant cross-section pipe piles and three step cross-scetion pipe piles are performed in lab respectively and some observation points are installed for heave amount and horizontal displacement of soil surface around piles before tests.Results show that penetration resistance improved linearly with increasing of length of pile in soil and there has a turning point which become more and more obviously with increasing of average diameter of step cross-section pipe pile after the pile length in soil is 70cm.Comparing with uniform cross-section pipe pile, penetration resistance per unit volume is more bigger and increases with improving of variable cross-section ratio to step cross-section pipe pile.The swelling-up amount of soil around step cross-section pipe pile increases firstly, then decreases secondly ,and increases finally. Camparing with uniform cross-section pipe pile, the maximum heaves have 51.0% and 44.6% reduce respectively to setp cross-section pipe pile and the position of largest heaves moved from 1.0d to 1.5d.Moreover, the largest horizontal displacements have 24.6% and 26.9% reduce respectively to step cros-section pipe pile and the point of largest horizontal displacement moved from 2.0d to 2.5d.

The Grouting Bored Pile Perfusing Pile Bearing Capacity after Effect Factors of the Finite Element Analysis

2012 ◽  
Vol 461 ◽  
pp. 351-354
Author(s):  
Shao He Li ◽  
Qun Xian Lin
Keyword(s):  
Finite Element ◽  
Comparative Analysis ◽  
Bearing Capacity ◽  
Influence Factors ◽  
Element Model ◽  
Model Parameters ◽  
Single Pile ◽  
Element Analysis ◽  
Bored Pile ◽  
After Effect

This article take the Zhejiang some project engineering geology condition as a background, Through comparative analysis with single pile load, determine the model parameters of ANSYS finite element, The ANSYS finite element model of single pile, Respectively on the Grouting pile and Grouting for grouting of pile modulus change and Grouting in body size and changes of modulus of pile-end soils and a series of comparative analysis of the situation and analysis on bearing capacity of bored pile tip Grouting influence factors and of the main causes, draw some useful conclusions.

Analysis of Principal Component - Application of SVM Model in Prediction of Ultimate Bearing Capacity of Static Pressure Pipe Pile

2012 ◽  
Vol 166-169 ◽  
pp. 1345-1352
Author(s):  
Jian Bin Zhao ◽  
Chao Xu ◽  
Hui Guo
Keyword(s):  
Bearing Capacity ◽  
Static Pressure ◽  
Principal Component ◽  
Ultimate Bearing Capacity ◽  
Support Vector ◽  
Pipe Pile ◽  
Pressure Pipe ◽  
Svm Model ◽  
Geological Conditions ◽  
The Impact

Vertical ultimate bearing capacity of static pressure pipe pile is influenced by comprehensive factors, such as pile body, soil around pile and construction conditions., and the relationship between the impact factors and ultimate bearing capacity of a single pile is highly complexity and non-linear. This paper is based on collecting the data from static load tests in typical geological conditions of Liao-shen area, construction records, and test pile sites. And then combine analysis of principal component with SVM to analysis the prediction of the single pile’s vertical ultimate bearing capacity. This model can reduce the number of SVM input variable dimension to improve speed of training support vector effectively. At the same time it can eliminate the influence factors of multiple correlation. The results show that the proposed principal component analysis SVM model has good predictive accuracy and generalization ability, and opens up new avenue of research for analysis of static pressure pipe pile vertical bearing properties.

Study on Vertical Bearing Capacity of the Riser Composite Pile in Clay

2018 ◽  
Author(s):  
Liang Chao ◽  
Liu Run ◽  
Wan Jun ◽  
Guan Pei ◽  
Li Xiangyun
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
Variable Cross Section ◽  
Small Scale ◽  
Variable Cross ◽  
Pile Diameter ◽  
Composite Pile ◽  
Calculation Results ◽  
S Curve ◽  
Vertical Bearing

In order to meet the development need of small-scale marginal oilfield, it is proposed to use the riser and surface casing to bear the loads replacing or partially replacing the steel pipe pile foundation. In this paper, the vertical bearing behavior of variable cross-section composite pile with the diameter of upper part larger than that of lower part (composed of riser and surface casing) is analyzed by finite element method. Then, the influences of different length combinations and diameter combinations of the composite pile on vertical bearing mechanism are studied, and the characteristics of stress concentration at the variable cross-section are revealed. The calculation results show that the increase in pile diameter, pile length and diameter ratio can effectively improve the bearing capacity of riser composite piles. The vertical ultimate bearing capacity of riser composite piles is greatly affected by upper part and less affected by lower part. The bearing capacity of lower part is gradually exerted, as the plastic zone appears at the end of the upper part, meanwhile, the Q-s curve shows as a broken line, which means that a larger pile top settlement is needed in order to effectively activate the bearing capacity of lower part.

scholarly journals Deformation behaviour of granular column reinforced by geosynthetic encasement

2021 ◽  
Vol 4 (2) ◽  
pp. first
Author(s):  
Lê Quân ◽  
Võ Đại Nhật ◽  
Nguyễn Việt Kỳ ◽  
Phạm Tiến Bách
Keyword(s):  
Bearing Capacity ◽  
Soft Soil ◽  
Thermal Power ◽  
Soil Improvement ◽  
Soft Ground ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Geological Conditions ◽  
Consolidation Settlement ◽  
Granular Column

In Vietnam, the overpopulation and strong economic development require the synchronous development of infrastructure such as roads, urban areas, industrial parks, export processing zones, etc. With such requirements, the development of land fund for infrastructure construction is an indispensable need. Meanwhile, the appropriate land fund is very limited. Therefore, the land fund must be developed for areas with little value for agriculture, such as swamps, estuaries, and coastal areas, etc. These areas often have weak geological conditions; hence, to meet the requirements of infrastructure construction on the soft ground, it is necessary to carry out soil improvement to ensure load bearing capacity, total settlement, and consolidation settlement but still ensuring economic effectiveness. Beside several conventional methods widely used for soft soil improvement in order to increase bearing capacity and accelerate consolidation settlement of the ground, geosynthetic reinforced granular column is one of the new methods that has been applied to improving soft ground in designing practice in the recent years due to the many advantages of this method compared with other methods. In this paper, based on the unit cell model, the authors research on deformation behavior of granular column reinforced by geosynthetic encasement through the analytical analysis by varying external loadings corresponding to column diameter, stiffness of geosynthetic encasement. The settlements of a single geosynthetic encased granular column and load bearing capacity of the composite foundation are calculated on geological conditions of Ash Pond Area of Song Hau 1 Thermal Power Plant located in Hau Giang Province. The relationship between settlement and load bearing capacity with external loadings for different column diameters and geosynthetic stiffnesses are shown schematically. Other considerations related to factor of safety are also presented. The future researches are also proposed.

scholarly journals Numerical Analysis of Bearing Behavior of the Prebored Precast Pile with an Enlarged Base

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zao Ling ◽  
Jiangbin Wu ◽  
Weidong Wang
Keyword(s):  
Numerical Analysis ◽  
Bearing Capacity ◽  
Soft Soil ◽  
Expansion Ratio ◽  
Construction Technology ◽  
Analysis Model ◽  
Obvious Effect ◽  
Soil Thickness ◽  
Finite Element Software ◽  
Cement Soil

Prebored precast pile with an enlarged base (PPEB pile) is a new type of green and environmental protection pile foundation developed in China in recent years, which has complex bearing characteristics and many influencing factors. Based on the static load tests and key parameters’ tests in deep soft soil in Shanghai, a three-dimensional numerical analysis model was established using ABAQUS finite element software. The transfer law of load among the precast pile, cement soil, and soil around the pile and the action mechanism of the enlarged base were analyzed emphatically, and a sensitivity analysis of the main factors affecting the bearing performance was carried out. The calculation results show that the existence of the enlarged base can greatly improve the compressive bearing capacity, increasing the diameter and height of the enlarged base is beneficial to the bearing capacity, and the influence of the diameter expansion ratio is more effective. With the increase of the proportion of nodular piles, the ultimate bearing capacity increases slightly, but the deformation increases obviously. Under the condition of cement soil of the test piles, the spacing of the neighboring nodules of nodular piles has no obvious effect on the bearing capacity, and the 1 m spacing commonly used in engineering applications can be optimized. The increase of cement soil thickness is beneficial to the improvement of pile bearing capacity, but the efficiency is low. Finally, some improvement measures for the construction technology of the PPEB pile were put forward.

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