scholarly journals Similitude Conditions Modeling Geosynthetic-Reinforced Piled Embankments Using FEM and FDM Techniques

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Keith Jennings ◽  
Patrick J. Naughton
Keyword(s):  
Load Transfer ◽  
The Finite Element Method ◽  
Soil Arching ◽  
Absolute Value ◽  
Load Transfer Mechanism ◽  
Pile Cap ◽  
Model Geometry ◽  
Piled Embankment ◽  
Characteristic Trend ◽  
Piled Embankments

The numerical modelling of geosynthetic-reinforced piled embankments using both the finite element method (FEM) and finite difference method (FDM) are compared. Plaxis 2D (FEM) was utilized to replicate FLAC (FDM) analysis originally presented by Han and Gabr on a unit cell axisymmetric model within a geosynthetic reinforced piled embankment (GRPE). The FEM and FED techniques were found to be in reasonable agreement, in both characteristic trend and absolute value. FEM consistently replicated the FDM outputs for deformational, loading, and load transfer mechanism (soil arching) response within the reinforced piled embankment structure with a reasonable degree of accuracy. However the FDM approach was found to give a slightly higher reinforcement tension and stress concentration but lower reinforcement strain at the pile cap than FEM, which was attributed to the greater discretize of the model geometry in the FDM than in FEM.

scholarly journals Analytical methods for stress transfer efficacy in the piled embankment

2020 ◽  
Vol 61 (HTCS6) ◽  
pp. 81-87
Author(s):  
Hung Van Pham ◽  
Phuc Dinh Hoang ◽  
Thinh Duc Ta ◽  
Keyword(s):  
Analytical Methods ◽  
Load Transfer ◽  
Soft Soil ◽  
Stress Transfer ◽  
Soil Improvement ◽  
Soil Arching ◽  
Negative Skin Friction ◽  
Load Transfer Mechanism ◽  
Improvement Method ◽  
Piled Embankment

Soft soil reinforced by rigid inclusions under embankment is a soft soil improvement method, known as a piled embankment. It has been widely studied and applied over the world, since 90’s decade of the last century. The behavior of a piled embankment is mainly based on the formation of soil arching within the embankment and the negative skin friction around inclusion shaft. The paper investigates the mechanical behavior of a piled embankment to make clear the load transfer mechanism of the method. Additionally, some of the analytical methods in determining the stress transfer efficacy are presented.

Load Transfer Mechanism of Embankment Supported by Sparse Piles

2012 ◽  
Vol 178-181 ◽  
pp. 1396-1401
Author(s):  
Hao Zhang ◽  
Ming Lei Shi ◽  
Rui Kun Zhang ◽  
Yu Zhao
Keyword(s):  
Present Method ◽  
Stress Ratio ◽  
Load Transfer ◽  
Vertical Load ◽  
Transfer Property ◽  
Arching Effect ◽  
Load Transfer Mechanism ◽  
Soil Stress ◽  
Load Effects ◽  
Piled Embankment

The load transfer property of embankment fills, cushion, pile (or with cap) and foundation soils are complicated in a piled embankment. In this paper, the vertical load effects of pile and foundation soils at the bottom of embankment were analyzed with consideration of the interaction of each component. The arching effect of embankment fills and the pile-soil interaction were respectively formulated, and then, with continuous displacements and stresses at the bottom of embankment, a calculation method of pile-soil stress ratio was presented. In addition, the influence of the setting of cushion and geosynthetic was analyzed. The present method could definite the load sharing between pile and soil, and may be applied in the engineering design of embankment supported by spares piles.

Load transfer mechanism of reinforced piled embankments

2018 ◽  
pp. 1031-1036
Author(s):  
M.S.S. Almeida ◽  
D.F. Fagundes ◽  
M.C.F. Almeida ◽  
D.A. Hartmann ◽  
R. Girout ◽  
...  
Keyword(s):  
Load Transfer ◽  
Transfer Mechanism ◽  
Load Transfer Mechanism ◽  
Piled Embankments

Analysis of Behavior of Composite Foundation with Sparse Pile to Control Settlement

2012 ◽  
Vol 204-208 ◽  
pp. 674-679
Author(s):  
Jun Hui Zhang ◽  
Zhi Yong Yin ◽  
Jian Long Zheng
Keyword(s):  
Load Transfer ◽  
Computer Code ◽  
Differential Settlement ◽  
Composite Foundation ◽  
Soil Arching ◽  
Arching Effect ◽  
Soil Arching Effect ◽  
Rapid Construction ◽  
Membrane Effect ◽  
Pile Cap

The composite foundation with sparse piles to control settlement has been used to rapid construction and strict deformation of the structure widely currently, which can enhance the efficient of load transfer and decrease the differential settlement used with the geosynthetic. Considering the confine of analytical solution and the traditional method with a changeless modulus of geosynthetic and pile, the effects of the height of fill, the elastic modulus of geosynthetic and pile material on the differential settlement, embankment soil arching effect and tensioned membrane effect etc. are investigated using the computer code ABAQUS in this paper. The results indicate that the modulus of geosynthetic and pile has a notable influence on the differential settlement and the arching effect, which should be considered in the design. At the same time, the maximum tension in geosynthetic occurs near the edge of the pile cap.

Load transfer mechanism and deformation of reinforced piled embankments

2017 ◽  
Vol 45 (2) ◽  
pp. 1-10 ◽  
Author(s):  
Diego F. Fagundes ◽  
Márcio S.S. Almeida ◽  
Luc Thorel ◽  
Matthieu Blanc
Keyword(s):  
Load Transfer ◽  
Transfer Mechanism ◽  
Load Transfer Mechanism ◽  
Piled Embankments

A Numerical Analysis of 3D Soil Arching in Piled Embankments

2014 ◽  
Vol 488-489 ◽  
pp. 346-349
Author(s):  
Min Zhao ◽  
Wei Ping Cao
Keyword(s):  
Tensile Strength ◽  
Numerical Analysis ◽  
Internal Friction ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Deformation Characteristics ◽  
Soil Arching ◽  
Pile Cap ◽  
Embankment Height ◽  
Piled Embankments

3D Soil arching has an important influence on the bearing and deformation characteristics of piled reinforced embankments. The effect of the embankment height, pile-cap clear spacing, cohesion and internal friction angle of the embankment fill on pile efficacy was analyzed by numerical method in this paper. The results indicate that the pile efficacy increases gradually during embankment filling and remains nearly unchanged at the end of embankment filling. The ratio of the embankment height to pile-cap clear spacing greatly influence the pile efficacy. The bigger the ratio, the bigger the pile efficacy. The internal friction angle of the fill material also has somewhat influence while the tensile strength of horizontal reinforcement and cohesion of the embankment fill have little effect on the pile efficacy.

Analysis of Soil Arch under Dynamic Load

2012 ◽  
Vol 193-194 ◽  
pp. 939-948
Author(s):  
Mei Fang Li ◽  
Quan Mei Gong ◽  
Shun Hua Zhou
Keyword(s):  
Dynamic Load ◽  
Load Transfer ◽  
The Finite Element Method ◽  
Negative Effects ◽  
Soil Arching ◽  
Transfer Path ◽  
Numerical Studies ◽  
Calculation Results ◽  
Total Settlement ◽  
Soil Arch

Aroused by the differential stiffness of pile and soil, the upper load on subgrade is apt to be transferred to pile rather than soil among piles in pile supported embankment(soil arching effect), which optimizes the load-transfer path and effectively limits total settlement of the subgrade. In this paper the properties of soil arch under dynamic load have been investigated by performing numerical studies using the Finite Element Method. The influence of stiffness difference between soil and pile on the soil arch is also proposed in this paper. According to the calculation results, the softer the soil between piles is, the larger proportion of load imposes on pile. Dynamic load has negative effects on the static soil arch, but it does not ruin the shape of the arch. Simultaneously, the larger N (the ratio of dynamic modulus of pile to that of soil)is, the weaker the negative effects of dynamic load on static soil arch are. The static soil arch (soil arch formed when the model only bears static load) has optimized the load transformation path, leading more load undertaken by the pile. Besides, When the stiffness difference between pile and soil among piles is relatively small, the height of soil arch increases sharply with the decrease of N; while when the stiffness difference reaches some certain value, the further increasing of N has little influence on soil arch’s height.

A Numerical Analysis of Soil Arching in Piled Embankments

2012 ◽  
Vol 468-471 ◽  
pp. 638-642
Author(s):  
Min Zhao ◽  
Wei Ping Cao
Keyword(s):  
Numerical Analysis ◽  
Stress Concentration ◽  
Concentration Ratio ◽  
Friction Angle ◽  
Relative Displacement ◽  
Soil Arching ◽  
Pile Cap ◽  
Stress Concentration Ratio ◽  
Embankment Height ◽  
Piled Embankments

Soil arching has important influence on the behavior of piled embankments. How to calculate stress concentration ratio is of great concern when designing embankment over soft soils reinforced by rigid concrete piles. A numerical analysis by using a commercial FEM program was conducted to reveal the mechanism of soil arching in piled embankments. And also, the influence of embankment height, pile-soil relative displacement, cohesion and internal friction angle on the equal settlement plane was evaluated. The results indicate that the stress concentration ratio varies with the pile-subsoil relative displacement and has upper and lower bound value. The effect of pile-soil displacement and the strength parameters of embankment material on the equal settlement plane can be neglected. It was also found that the equal settlement plane height is equal to 1.6 times the pile-cap clear spacing. When the ratio of embankment height to the pile-cap clear spacing is greater than 1.6, no apparent differential settlement will occur on the embankment surface.

scholarly journals Soil Arching of Piled Embankment in Equal Settlement Pattern: A Discrete Element Analysis

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1627
Author(s):  
Kangyu Wang ◽  
Jun Cao ◽  
Xinquan Wang ◽  
Yingjie Ning
Keyword(s):  
Slip Surface ◽  
Discrete Element ◽  
Settlement Pattern ◽  
Differential Settlement ◽  
Test Model ◽  
Soil Arching ◽  
Element Analysis ◽  
Arching Effect ◽  
Pile Cap ◽  
Piled Embankment

Soil arching, which occurs in the piled embankments, plays an important role in stress redistribution between the relatively soft subsoil and the stiffer piles. The formation of the soil arching depends on the differential settlement of the embankment fill above the pile and the subsoil. The soil arching effect is barely investigated in the literature from the perspective of differential settlement of piles and soils. Based on the discrete element method (DEM), this paper develops a classic trapdoor test model to investigate the differential settlement in piled embankment during the downward movement of the trapdoor, and to explore the formation mechanism of soil arching in equal settlement pattern by changing the width of the pile cap and the height of the embankment. Due to symmetry, only one section of the laboratory test model is simulated herein. It was found that the soil arching formed under the equal settlement pattern remained unchanged after a certain degree of development, and the height of the equal settlement did not change at 0.7(s-a), where s is the pile spacing, and a is the width of the pile cap. The height of the embankment (H) and the width of the pile cap (a) have a significant influence on the formation of the equal settlement pattern when the width of the trapdoor is kept constant. Both the decrease in “H” and the increase in “a” facilitate the differential settlement of the soil between the piles and the pile-soil, enabling the slip surface to develop upward gradually, thereby hindering the formation of the equal settlement pattern.

scholarly journals DEM Simulation of the Load Transfer Mechanism of a GRPS Embankment with a Fixed Geogrid Technique

2021 ◽  
Vol 11 (19) ◽  
pp. 8814
Author(s):  
Jun Zhang ◽  
Yafei Jia ◽  
Yewei Zheng ◽  
Chenxi Miao
Keyword(s):  
Contact Force ◽  
Load Transfer ◽  
Differential Settlement ◽  
Force Chain ◽  
Soil Arching ◽  
Load Bearing ◽  
Load Transfer Mechanism ◽  
Membrane Effect ◽  
Surcharge Load ◽  
Grps Embankment

As a new technique, a fixed geogrid in a geogrid-reinforced and pile-supported (GRPS) embankments has been used to reduce the total and differential settlement. To investigate the load transfer mechanism of the fixed geogrid technique of a GRPS embankment, three discrete element method (DEM) models of pile-supported embankments were established, including an unreinforced embankment, a geogrid reinforced embankment, and a fixed geogrid reinforced embankment. The efficacy of the pile, the evolution law of the contact force chain and the axial force of the reinforcement, and the microscopic load-bearing structure of the soil were investigated. Numerical simulation results showed that the embankment self-weight and surcharge load were transferred to the pile through the soil arching and tensile membrane effect. The settlement could be effectively reduced via the addition of the reinforcement, and the fixed geogrid technique was more conducive to improving the load-bearing ratio of the pile than the traditional reinforcement technique. Compared with the traditional technique of a GRPS embankment, the fixed geogrid technique had a better effect on reducing the total and differential settlement. With the increase in the surcharge load and the settlement of the soft subsoil, the reinforcement transferred a greater load to the pile. The results also showed that the stress of the embankment fill was concentrated at the pile top in all three models. The GRPS embankment with a fixed geogrid technique had a lower soil stress concentration than the other two cases. The contact force chain and stress in the embankment also showed that the reformation of the microscopic load-bearing system of the embankment fill was the internal mechanism that caused the development of the soil arching and the redistribution of stress. Furthermore, the evolution of the fabric parameters in the arching area could reflect the evolution of the soil arching structure. In the fixed geogrid case, the proportion of the load transferred to the pile from the soil arching effect was reduced, and the vertical load transferred to the pile top by the tensile membrane effect accounted for 22–28% in this study. Under the combined effect of the tensile membrane and the soil arching, the efficacy of the pile could increase by 10%.

Sign in / Sign up

Export Citation Format

Share Document