scholarly journals PREDICTABILITY OF THE INTERNATIONAL GEOTECHNICAL CODE FOR THE ESTIMATING ULTIMATE BEARING CAPACITY OF LARGE-DIAMETER BORED PILES

2013 ◽  
Vol 1 (1) ◽  
pp. 540-550
Author(s):  
Mahmoud F. AWAD-ALLAH ◽  
Noriyuki YASUFUKU
Keyword(s):  
Bearing Capacity ◽  
Large Diameter ◽  
Ultimate Bearing Capacity ◽  
Bored Piles

scholarly journals Ultimate Load Tests on Bearing Behavior of Large-Diameter Bored Piles in Weathered Rock Foundation

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Xiaoyu Bai ◽  
Xueying Liu ◽  
Mingyi Zhang ◽  
Yonghong Wang ◽  
Nan Yan
Keyword(s):  
Bearing Capacity ◽  
Limit State ◽  
Large Diameter ◽  
Diameter Ratio ◽  
Load Test ◽  
Single Pile ◽  
Rock Foundation ◽  
Deformation Characteristics ◽  
Lateral Resistance ◽  
Bored Piles

Based on the vertical compressive static load test and pile mechanics test of three large diameter bored piles (one of the test piles was treated with postgrouting) in granite gneisses foundation, the bearing capacity, deformation characteristics, and influencing factors of the single pile under the limit state are analyzed and compared with the recommended values of survey report and the recommended values of current codes. By comparing the measured and theoretical values of pile axial force, the bearing capacity of cast-in-place pile under normal and limit conditions is analyzed. The experimental results show that the Q-s curve of large-diameter rock-socketed mud wall retaining bored pile with a length-diameter ratio of 25–33 and rock-socketed depth of 5–8 d shows a rapid growth. After grouting treatment, the ultimate compressive bearing capacity of single pile is improved, the maximum settlement is reduced by 6.6%, the rebound rate is reduced by 11.1%, and the settlement effect of controlling pile top is not significant. The bearing capacity and deformation characteristics of the three test piles are less affected by length-diameter ratio and rock-socketed depth. For postgrouting piles, the ratio of frictional resistance of rock-socketed segment and the ratio of pile lateral resistance are less affected by length-diameter ratio and rock-socketed depth, while, for postgrouting piles, the ratio of pile lateral resistance is more affected by rock-socketed depth. The pile end resistance ratio of the three test piles is significantly affected by the rock-socketed depth, whether or not the pile side postgrouting treatment is carried out.

Analysis of Distribution Characteristics and Reliability for Bearing Capacity of Piles

2014 ◽  
Vol 638-640 ◽  
pp. 365-369
Author(s):  
Shu Jun Zhang ◽  
Zhi Jun Xu ◽  
Kai Wang ◽  
Bo Zhang
Keyword(s):  
Bearing Capacity ◽  
Ultimate Bearing Capacity ◽  
Distribution Characteristics ◽  
Driven Piles ◽  
Performance Function ◽  
Shaft Resistance ◽  
Bored Pile ◽  
Tip Resistance ◽  
Bored Piles ◽  
The Impact

This paper aims to study the distribution characteristics of the ratio of measured value and calculated value for ultimate bearing capacity, shaft resistance and tip resistance, and discuss the impact of shaft resistance and tip resistance on ultimate bearing capacity. A new performance function is proposed in terms of the three types of bearing capacity mentioned ahead. Take bored piles and driven piles for example, and the results from analysis indicate that the ratio of the measured value to calculated value of bored piles ranges from 0.75 to 1.45, and mostly is greater than 1.0; The ratio of the measured to predicted bearing capacity of driven piles lies between 0.8 and 1.5, and is larger than the corresponding ratio of bored piles. In addition, the reliability of tip resistance is lager than that of shaft resistance for bored pile, while the reliability of tip resistance is less than that of shaft resistance for driven piles. Meanwhile, the method presented in this paper can offer references to designers for revising and improving the technical code for pile foundations.

Comparison and Analysis of the Calculation Formulas for the Bearing Capacity of Concrete Filled Steel Tubular Columns

2014 ◽  
Vol 1065-1069 ◽  
pp. 1337-1340
Author(s):  
Jin Sheng Han ◽  
Xue Wen Wang ◽  
Li Yi Wang ◽  
Min Ji
Keyword(s):  
Bearing Capacity ◽  
Large Diameter ◽  
Ultimate Bearing Capacity ◽  
Test Results ◽  
Tubular Columns ◽  
Steel Bars ◽  
Calculation Results ◽  
Comparison And Analysis ◽  
Numerous Calculation ◽  
Application Scope

At present, many analysis methods and calculation formulas of the bearing capacity of concrete filled steel tubular columns have been researched. But these numerous calculation formulas of the bearing capacity have varied forms, and the application scope and the calculation precision of them are also quite different, which makes it difficult and confused for engineering designer to choose a suitable formula. Primary calculation formulas of the bearing capacity of concrete filled steel tubular columns are summarized. The calculation results of these formulas are compared with some test results of the concrete filled steel tubular columns with a large diameter. The applicability and the accuracy of these formulas are analyzed. Based on these comparisons and analyses, reasonable suggestion is given to select the suitable formula. Finally, one formula is provided to calculate the ultimate bearing capacity of concrete filled steel tubular columns reinforced with steel bars.

Numerical Simulation Analysis of Bearing Performance of Extra-Long and Large-Diameter Single Pile

2014 ◽  
Vol 1065-1069 ◽  
pp. 943-948
Author(s):  
Zhi Meng Zhao ◽  
Jin Yi Chai ◽  
Cai Xia Fan
Keyword(s):  
Numerical Simulation ◽  
Elastic Modulus ◽  
Bearing Capacity ◽  
Simulation Analysis ◽  
Large Diameter ◽  
Ultimate Bearing Capacity ◽  
Single Pile ◽  
Pile Shaft ◽  
Settlement Ratio ◽  
Pile Length

The effects of pile diameter, the property of pile end bearing stratum, the material parameters of pile shaft and the changes of pile length on the bearing performance of extra-long and large-diameter single pile were examined with the finite element software ABAQUS to make the numerical simulation analysis, by establishing the overall axial symmetry model, which was based on the data of static load test of single pile at the Yellow River Bridge site. The results show that the ultimate bearing capacity of single pile, the stiffness and the end resistance ratio would increase gradually, whereas the compression settlement ratio decreases slowly; the pile end grouting can significantly increase the ultimate loads, and therefore, improve the bearing performance of piles, but it has little effect on the stiffness of pile when loading was smaller; the elastic modulus of pile shaft has no effect on the ultimate bearing capacity of friction piles, little on the end resistance ratio, while the pile compression settlement ratio would gradually decrease and the stiffness would increased with the increase of the elastic modulus of pile shaft, and this increase of stiffness would slow down with the increase of elastic modulus of pile shaft; it is unreasonable to improve the ultimate bearing capacity of extra-long single pile only by means of increasing the pile length.

Efficiency of Pile Groups of Large Diameter Bored Cast-in-Place Pile

2011 ◽  
Vol 261-263 ◽  
pp. 1215-1219 ◽  
Author(s):  
Xiu Bin Gong ◽  
Qing Lai Fan ◽  
Yong Jie Xu
Keyword(s):  
Numerical Analysis ◽  
Bearing Capacity ◽  
Large Diameter ◽  
Three Dimensional ◽  
Ultimate Bearing Capacity ◽  
Efficiency Factor ◽  
Pile Groups ◽  
Pile Spacing ◽  
Vertical Loading

Based on the framework of the FEM, the three-dimensional numerical analysis for evaluating the efficiency of pile groups of large diameter bored cast-in-place pile is conducted in this paper. The effect of the pile numbers and pile spacing on the efficiency of pile groups is obtained by studying the ultimate bearing capacity behavior of different arrangements of pile groups under vertical loading. Then they are compared with the calculated results gained by the formula of the efficiency factor of the pile groups based on superimposed stresses. The findings can serve as a reference for the design of large diameter bored cast-in-place pile.

A Grey Correlation Model for Analyzing Ultimate Bearing Capacity of Large Diameter and Super-Long Pile

2011 ◽  
Vol 138-139 ◽  
pp. 786-792
Author(s):  
Jie Wen Tu ◽  
Ai Ping Tang
Keyword(s):  
Correlation Analysis ◽  
Bearing Capacity ◽  
Large Diameter ◽  
Ultimate Bearing Capacity ◽  
Diameter Ratio ◽  
Correlation Model ◽  
Grey Correlation ◽  
Correlation Degree ◽  
Grey Correlation Analysis ◽  
Length To Diameter Ratio

Large diameter and super-long pile has found abroad application in high buildings, super high buildings, large bridges and port engineering, and its ultimate bearing capacity is increasingly demanding. Its ultimate bearing capacity is affected by many kinds of uncertainty factors, which is a complex grey analysis program. The influencing factors are analyzed by grey system theory such as pile diameter, pile length, socket length, the length to diameter ratio, the socket length to diameter ratio, rock strength and rock coefficient of weathering. The grey correlation analysis is combined with the tested statistical data of 19 large diameter and super-long piles in Zhejiang province based on the grey correlation model. With the objective to overcome the lack of objectivity in calculating correlation degree of the grey correlation analysis, this paper has improved the calculated formula of the correlation degree based on the distance analysis method. The paper has get and compared the corresponding result of the correlation degree and its rank of various influence factors with the improved calculated formula and the original formula respectively. The influence advantage factors found by grey correlation analysis, and the results can provide important reference for the future theoretical research and design application of large diameter and super-long pile, and show that the grey correlation method is effective and reliable.

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