Optimum Design Study on Leveling Variable Stiffness of Composite Foundation with Rammed Soil-Cement Pile

2010 ◽  
Vol 168-170 ◽  
pp. 2631-2635
Author(s):  
Zhen Shuan Zhang ◽  
Yu Deng ◽  
Wei Zhang ◽  
De Sheng Ju

According to the practical project, settlement, reaction and bending moment of composite foundation with rammed soil-cement pile are recalculated, which based on the change of the original area replacement ratio, pile length and foundation thickness. The method of optimum design study on leveling variable Stiffness is investigated.

2012 ◽  
Vol 256-259 ◽  
pp. 612-615
Author(s):  
Gui Lin Sheng ◽  
Ya Ge Zhang

The axial stress and axial displacement distribution curves of reinforced mixing single pile are researched by ANSYS software; and the differences of the single pile ultimate capacity of reinforced mixing pile between different core pile length and area replacing ratio are analyzed; It compared and analyzed envelope diagrams of bending moment and shear of reinforced mixing pile in different core pile length and area replacing ratio under seismic response. Some conclusions which may be of some value for design and construction of reinforced mixing pile composite foundation are drawn


2013 ◽  
Vol 405-408 ◽  
pp. 216-220
Author(s):  
Jing Qin ◽  
Wei Lu ◽  
Yun Zhao

The calculation equations of soil-column area replacement ratio (m) recommended by Chinese code Technical Code for Ground Treatment of Buildings (JGJ79-2012) have many limits in the practice. In this document, general equations of m value are derived by subdividing the composite soil element under the different pile arrangements. The results show that m value is determined by the two parameters: interval number among piles (n) and pile diameter-spacing ratio (d/s). m value greatly decreases with the increase of d/s at the constant n, whereas m slightly decreases with the increase of n at the constant d/s, and the larger n, the smaller drop of m value. Under triangular pile arrangement, the Chinese code recommended equations can be used with less than 10 percent of error ratio of m value when the width of composite foundation is above 10 m, but the general equations should be applied when the width is below 10 m. Under square pile arrangement, the recommended equations can be used when the width of composite subgrade is above 15 m, but the general equations should be applied when the width is below 15 m. The general calculation equations of m value derived in this paper can provide certain reference for theoretical calculation and engineering application.


2013 ◽  
Vol 639-640 ◽  
pp. 644-647
Author(s):  
Rong Yu ◽  
Xin Sheng Ge

It is used as an example that the composite foundation with long-short-piles is used in liquefied soil under a high-rise building .By using the finite element method, the effects of short pile replacement ratio, long pile replacement ratio, raft thickness on side friction of the pile are discussed respectively. The results show that: Short pile replacement ratio changes have an effect on side friction of the long pile from 4m to 15m. With long pile replacement ratio increasing, negative friction and positive friction of the long pile decreases gradually. With the raft thickness increasing, negative friction and positive friction of the long pile decreases gradually. Otherwise, the distance of side friction of the long pile comes up to zero increase gradually. These conclusions are provided as references for future optimum design.


2014 ◽  
Vol 1065-1069 ◽  
pp. 19-22
Author(s):  
Zhen Feng Wang ◽  
Ke Sheng Ma

Based on ABAQUS finite element analysis software simulation, the finite element model for dynamic analysis of rigid pile composite foundation and superstructure interaction system is established, which selects the two kinds of models, by simulating the soil dynamic constitutive model, selecting appropriate artificial boundary.The influence of rigid pile composite foundation on balance and imbalance of varying rigidity is analyzed under seismic loads. The result shows that the maximum bending moment and the horizontal displacement of the long pile is much greater than that of the short pile under seismic loads, the long pile of bending moment is larger in the position of stiffness change. By constrast, under the same economic condition, the aseismic performance of of rigid pile composite foundation on balance of varying rigidity is better than that of rigid pile composite foundation on imbalance of varying rigidity.


2013 ◽  
Vol 740 ◽  
pp. 655-658
Author(s):  
Huan Sheng Mu ◽  
Ling Gao

Through the practice of tamped cement soil pile in treatment of soft soil foundation in Guan to Shenzhou section of Daqing-Guangzhou Expressway, the author expounds the action mechanism of rammed soil cement pile, composite foundation design points and calculation method of bearing capacity characteristic value.


2021 ◽  
Vol 7 (4) ◽  
pp. 730-746
Author(s):  
Amanpreet Kaur ◽  
Harvinder Singh ◽  
J. N. Jha

This paper presents the results of three dimensional finite element analysis of laterally loaded pile groups of configuration 1×1, 2×1 and 3×1, embedded in two-layered soil consisting of soft clay at liquid limit overlying dense sand using Plaxis 3D. Effects of variation in pile length (L) and clay layer thickness (h) on lateral capacity and bending moment profile of pile foundations were evaluated by employing different values of pile length to diameter ratio (L/D) and ratio of clay layer thickness to pile length (h/L) in the analysis. Obtained results indicated that the lateral capacity reduces non-linearly with increase in clay layer thickness. Larger decrease was observed in group piles. A non-dimensional parameter Fx ratio was defined to compare lateral capacity in layered soil to that in dense sand, for which a generalized expression was derived in terms of h/L ratio and number of piles in a group. Group effect on lateral resistance and maximum bending moment was observed to become insignificant for clay layer thickness exceeding 40% of pile length. For a fixed value of clay layer thickness, lateral capacity and bending moment in a single pile increased significantly with increase in pile length only up to an optimum embedment depth in sand layer which was found to be equal to three times pile diameter and 0.21 times pile length for pile with L/D 15. Scale effect on lateral capacity has also been studied and discussed. Doi: 10.28991/cej-2021-03091686 Full Text: PDF


2014 ◽  
Vol 587-589 ◽  
pp. 928-933 ◽  
Author(s):  
Feng Lian ◽  
Zhi Liu ◽  
Jie Xu ◽  
Qiang Wang ◽  
Xian Hu Hu ◽  
...  

Two experimental areas in a highway soft soil ground treatment project in Guangdong Province were designed to investigate the improvement mechanism of geogrid-reinforced and pile-supported embankment(GRPS).The experimental results showed: In End-bearing Pile Area,the differential settlement between pile and soil was bigger than that of Floating Pile Area,so the bearing capacity of soil was exerted to a certain extent in Floating Pile Area. The bearing efficacy of soil below the pile cap was little, so the replacement ratio of composite foundation could be calculated according to the pile cap dimension. The load transfer efficacy of the geogrid was better than that of the soil arch. Five kinds of methods were used to evaluate the soil arch in the fill and it was indicated that the results calculated by the BS8006 method and Carlsson method was close to the experimental data which was smaller than results calculated by Hewlett method and Terzaghi method, bigger than Guido method. Through the analysis of the pile-soil stress ratio, the improvement mechanism of the two types of GRPS were revealed.


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