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.

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

2012 ◽  
Vol 204-208 ◽  
pp. 664-669
Author(s):  
Jun Hui Zhang ◽  
Zhi Yong Yin ◽  
Jian Long Zheng
Keyword(s):  
Elastic Modulus ◽  
Significant Influence ◽  
Computer Code ◽  
Differential Settlement ◽  
Composite Foundation ◽  
Soil Arching ◽  
Maximum Settlement ◽  
Arching Effect ◽  
Soil Arching Effect ◽  
Pile Cap

The embankment soil arching effect of the composite foundation with sparse piles to control settlement is caused by the differential settlement between the embankment fill and the piles. So, the settlement is an important behaviour of the composite foundation. The effects of the height of embankment, the elastic modulus of geosynthetic and pile material, the stiffness of cushion and substratum, the pile cap and the distance of piles on the settlement are investigated using the computer code ABAQUS in this paper. The results indicate that the maximum settlement and differential settlement decrease with the elastic modulus of geosynthetic, the stiffness of cushion and substratum. The maximum settlement decreases and the differential settlement increases with the elastic modulus of pile material. At the same time, the differential settlement of the embankment surface decreases with the height of fill and there will be an equal settlement plane when the fill reaches certain height. In addition, the distance of piles has a more significant influence on settlement than the dimension of pile cap.

Study on Load-Bearing Mechanism of Stabilizing Pile-Groups by FEM and its Application

2014 ◽  
Vol 638-640 ◽  
pp. 656-670
Author(s):  
Huan Feng Qiu ◽  
Shao Jun Fu
Keyword(s):  
Computer Code ◽  
Soil Mass ◽  
Design Parameters ◽  
Pile Groups ◽  
Soil Pressure ◽  
Soil Arching ◽  
Fine Grained ◽  
Arching Effect ◽  
Soil Arching Effect ◽  
Pile Diameter

The behaviour of pile-groups subjected to lateral soil pressure is a key consideration in establishing the design parameters of pile-groups. In this paper, one representative section of the Chongqing Jiangdong slope is taken as an example. The existence of an arching zone around pile groups for granular and fine-grained soils is first examined using the finite element computer code CORE-3D. Pile load-displacement curves and the arching effect are considered together to explain how the stresses are transferred from the soil to the piles. The key parameters controlling the soil arching effect are centre-to-centre pile spacing (S), thickness of stable soil mass (H), depth (L) of pile embedment, pile diameter (D) and these were studied extensively. An empirical equation summarising the results is presented and the results have been adopted by the designer in practice.

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%.

scholarly journals Full-scale model study on variations of soil stress in geosynthetic-reinforced pile-supported track bed with water level change and cyclic loading

2019 ◽  
Vol 56 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Han-Lin Wang ◽  
Ren-Peng Chen ◽  
Wei Cheng ◽  
Shuai Qi ◽  
Yu-Jun Cui
Keyword(s):  
Cyclic Loading ◽  
Water Level ◽  
High Water ◽  
Scale Model ◽  
Soil Arching ◽  
Arching Effect ◽  
Soil Arching Effect ◽  
Soil Stress ◽  
Pile Cap ◽  
Level Lowering

This study presents a full-scale model investigation on variations of soil stress in a geosynthetic-reinforced pile-supported track bed at various water levels and loading cycles, with four testing procedures: water level rising, cyclic loading at high water level, water level lowering, and cyclic loading at low water level. The soil arching effect was revealed, characterized by higher stress above the pile cap. With the water level rising and loading cycles increasing at high water level, this effect becomes more pronounced, until a peak value of dynamic stress concentration ratio is reached. The stable state of soil arching is obtained earlier near the crown of soil arching, but this arching effect develops more significantly at the foot of soil arching. With the water level lowering and loading at low water level, the soil arching effect remains steady, with slightly changed dynamic stresses in the track bed. The geogrid shows a significant impact on the load transfer mechanism for the quasi-static stress: the quasi-static pile-cap stress presents higher values below the geogrid, whereas the opposite trend is observed for the water-bag (subsoil) area. Nevertheless, this mechanism is not obvious with respect to the dynamic stress, with the values showing no distinct difference above and below the geogrid.

scholarly journals A Theoretical Solution for Pile-Supported Embankment with a Conical Pile-Head

2019 ◽  
Vol 9 (13) ◽  
pp. 2658 ◽  
Author(s):  
Chengfu Zhang ◽  
Minghua Zhao ◽  
Shuai Zhou ◽  
Zeyu Xu
Keyword(s):  
Load Transfer ◽  
Cell Model ◽  
Theoretical Solution ◽  
Model Parameters ◽  
Pile Head ◽  
Soil Arching ◽  
Arching Effect ◽  
Soil Arching Effect ◽  
Comparative Results ◽  
Pile Supported Embankment

This paper, with a focuses on the pile-supported embankment with a conical pile-head, proposes a theoretical solution which incorporates all the load transfer mechanisms, namely the soil arching effect, the pile–soil interaction, and the support from the substratum, whilst an improved cylindrical unit cell model is introduced to analyze the soil arching effect. The theoretical solution has been verified via numerical analysis and a literature method. The comparative results indicate that the proposed theoretical solution can effectively evaluate the pile-supported embankment with a conical pile-head. Furthermore, parametric studies have also been conducted to analyze the effect of model parameters on the load sharing ratio (ne), the pile–soil stress ratio (n), and the pile shaft friction.

Field Study of Improvement Mechanism of Geogrid-Reinforced and Pile-Supported Embankment

2014 ◽  
Vol 587-589 ◽  
pp. 928-933 ◽  
Author(s):  
Feng Lian ◽  
Zhi Liu ◽  
Jie Xu ◽  
Qiang Wang ◽  
Xian Hu Hu ◽  
...  
Keyword(s):  
Load Transfer ◽  
Soft Soil ◽  
Composite Foundation ◽  
Replacement Ratio ◽  
Floating Pile ◽  
Pile Cap ◽  
Soil Arch ◽  
Better Than ◽  
End Bearing Pile ◽  
Pile Supported Embankment

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.

scholarly journals Pile-Spacing Calculation of Anti-Slide Pile Based on Soil Arching Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-6 ◽  
Author(s):  
Guangfu Chen ◽  
Liangchao Zou ◽  
Qing Wang ◽  
Guodong Zhang
Keyword(s):  
Load Capacity ◽  
Limit Equilibrium ◽  
Interaction Mechanism ◽  
Soil Arching ◽  
Pile Spacing ◽  
Arching Effect ◽  
Soil Arching Effect ◽  
Engineering Designs ◽  
Practical Engineering ◽  
The Difference

Anti-slide pile is one of the most frequently used measures in landslide control globally. Pile-spacing has always been determined by the load capacity of single piles or according to engineering empirical experience. Many engineering practices and laboratory experiments show that the soil arching effect exists in landslide control with anti-slide piles. In this study, we aim to calculate pile-spacing in terms of the soil arching effect. We investigated the pile-soil interaction mechanism and propose that, at the limit, the pile-back soil arch resists landslide thrust only. According to Mohr–Coulomb strength theory and limit equilibrium theories, we derived a new pile-spacing calculation equation. We verified the derived pile-spacing calculation equation with real projects. The calculated results are similar to those of practical engineering designs, in which the difference is within 10%. The equation can be used in anti-slide pile preliminary design. This study can be a reference for pile-spacing calculation based on the soil arching effect.

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