Modelling effects of pile diameter

2016 ◽  
Vol 53 (1) ◽  
pp. 173-178 ◽  
Author(s):  
W.D. Liam Finn ◽  
J. Dowling
Keyword(s):  
Small Diameter ◽  
Field Tests ◽  
Technical Note ◽  
American Petroleum Institute ◽  
Finite Element Program ◽  
Model Soil ◽  
Pile Diameter ◽  
Element Program ◽  
Load Tests ◽  
Diameter Effect

The most commonly used program for the analysis of piles under static lateral loading is LPILE. The program uses the nonlinear Winkler springs recommended by the American Petroleum Institute (API) to model soil–pile interaction. The p–y (load–displacement) curves were developed from field tests, with pile diameters in the range 0.324–0.67 m. When these p–y curves are used to analyze load tests on piles with larger diameters, the computed load–deflection curves underestimate the stiffnesses of the test piles. This effect is referred to as the pile diameter effect. In this technical note, a very different approach is presented to evaluate the pile diameter effect. Both LPILE and a continuum-based finite element program VERSAT-P3D were calibrated to closely simulate the results of two lateral load tests on small-diameter piles at two different sites. VERSAT-P3D modelled the volume of the pile and LPILE did not. Each program was used to develop p–y curves for increasingly larger pile diameters up to 2.0 m. An important finding for practice is that there was no pile diameter effect for displacements up to 60 mm. LPILE can be used with confidence in practice in this displacement range. Thereafter, the load–deflection curves from LPILE became softer and the pile diameter effect became evident.

scholarly journals Favorable of grouted micropiles for the load transfer in weak sandy soils

2018 ◽  
Vol 162 ◽  
pp. 01018
Author(s):  
Ahmed Al-Obaidi ◽  
Ansam Al-Karawi
Keyword(s):  
Load Transfer ◽  
Small Diameter ◽  
Axial Loading ◽  
Type A ◽  
Ultimate Capacity ◽  
Finite Element Program ◽  
Axial Capacity ◽  
Type D ◽  
Element Program ◽  
Pressure Grouting

Micropiles are defined as small diameter piles, implemented as a cast-in-place replacement or injected grout. Generally assumed with a diameter less than 300 mm. The axial capacity of micropiles develops primarily through the bond between gravity grouted (Type A) or post grouted (Type B, C or D) and soil in bonded zone of the micropile. Because of this, micropiles are useful in a variety of applications. Micropiles (Type D) indicate a two-step process of grouting, neat cement grout is placed under gravity head, then, additional grout is injected via a sleeved grout pipe at a specified pressure. In this research, a numerical model was developed to simulate the properties of the micropile (Type D), in addition to micropile (Type A). A general finite element program ABAQUS was selected for the numerical analysis method and for generating the solution. The parameters that affect the load transfer and ultimate capacity of the micropile foundation, which includes micropile length, diameter, grouted length and weak soil type, were investigated. The main results show that the pressure grouting micropile provides better load transfer mechanism as it makes surrounding soil strength to be fully mobilized upon axial loading. Micropiles (Type D)show more favorable in a capacity where the increment range is up to 50% as compared with groundgrouted micropiles (Type A). In addition, the results indicate that the ultimate capacity of micropile increases as the grouted length increases.

scholarly journals Tests on Model Piled Rafts in Sand: Measured Settlements Compared with Finite Element Predictions

2021 ◽  
Author(s):  
Joshua Omer ◽  
Hasan Haroglu
Keyword(s):  
Finite Element ◽  
Load Transfer ◽  
Strain Gauges ◽  
Valuable Insight ◽  
Finite Element Program ◽  
Soil Stiffness ◽  
Piled Raft ◽  
Pile Diameter ◽  
Element Program ◽  
Single Piles

AbstractLaboratory tests were carried out on non-piled rafts, single piles, surface contacting and non surface-contacting piled rafts which were made of aluminum and instrumented with strain gauges and deflection gauges. The foundations were installed in dry sand contained in a large metal tank to minimize boundary effects. Maintained loads were applied to each foundation until failure was closely approached. In parallel, analyses were performed using PLAXIS™ 3-D finite element program to compare the calculated and measured load-settlement trends hence assess the influence of soil stiffness on the foundation behaviour. The results confirmed that group efficiency of non-surface contacting piled increased with increasing pile–pile spacing and approached unity at a spacing equivalent to 8D (D = pile diameter). The data obtained from the strain gauges provided valuable insight into the load-transfer characteristics of different foundations and subsequently proved that the capacity of a surface contacting piled raft is significantly enhanced compared to that of either a non-piled raft or a non-surface contacting piled raft.

Investigation on Behavior of Rock-Socketed Retaining Piles for Deep Excavation

2011 ◽  
Vol 462-463 ◽  
pp. 825-830
Author(s):  
Xiao Li Liu ◽  
H. Zhou
Keyword(s):  
Shear Force ◽  
Bending Moment ◽  
Force Distribution ◽  
Rock Layer ◽  
Deep Excavation ◽  
Finite Element Program ◽  
Deep Excavations ◽  
Pile Diameter ◽  
Dimensional Finite Element ◽  
Element Program

In the soil-rock mixed areas where the soils overlie on the rock layer, the rock-socketed retaining piles have been widely used for deep excavations. Up to date, little attention has been paid to performance of the rock-socketed piles used for deep excavation. Therefore, using the two-dimensional finite element program, Plaxis2D, a typical deep excavation engineering supported by rock-socketed piles with the whole embedded portion in rock is analyzed to investigate behavior of the rock-socketed retaining piles in detail. Computation results have shown that for rock-socketed retaining piles used in deep excavations, there exists an ultimate or a maximum rock-socketed depth which can be estimated by the pile diameter. For the ultimate rock-socketed depth, in the final excavation step, the first zero bending moment point of the rock-socketed part of the pile generally locates near the top surface of the rock layer. When the excavated surface is located at the top surface of the rock layer, the corresponding shear force distribution of the rock-socketed pile has an extremum at the same position.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

scholarly journals The impact of drilling and slitting construction on damage field: evolution characteristics in low-permeability coal seam

2021 ◽  
Vol 37 ◽  
pp. 205-215
Author(s):  
Heng Chen ◽  
Hongmei Cheng ◽  
Aibin Xu ◽  
Yi Xue ◽  
Weihong Peng
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Damage Mechanics ◽  
Effective Strain ◽  
Secondary Development ◽  
Distribution Area ◽  
Finite Element Program ◽  
Element Program ◽  
Mining Face ◽  
The Impact

ABSTRACT The fracture field of coal and rock mass is the main channel for gas migration and accumulation. Exploring the evolution law of fracture field of coal and rock mass under the condition of drilling and slitting construction has important theoretical significance for guiding efficient gas drainage. The generation and evolution process of coal and rock fissures is also the development and accumulation process of its damage. Therefore, based on damage mechanics and finite element theory, the mathematical model is established. The damage variable of coal mass is defined by effective strain, the elastoplastic damage constitutive equation is established and the secondary development of finite element program is completed by FORTRAN language. Using this program, the numerical simulation of drilling and slitting construction of the 15-14120 mining face of Pingdingshan No. 8 Mine is carried out, and the effects of different single borehole diameters, different kerf widths and different kerf heights on the distribution area of surrounding coal fracture field and the degree of damage are studied quantitatively. These provide a theoretical basis for the reasonable determination of the slitting and drilling arrangement parameters at the engineering site.

Mechanical Property Analysis and Numerical Simulation of Honeycomb Sandwich Structure’s Core

2013 ◽  
Vol 631-632 ◽  
pp. 518-523 ◽  
Author(s):  
Xiang Li ◽  
Min You
Keyword(s):  
Numerical Simulation ◽  
Elastic Constants ◽  
Sandwich Structure ◽  
Optimization Design ◽  
Simulation Analysis ◽  
Finite Element Program ◽  
Honeycomb Sandwich ◽  
Calculation Results ◽  
Element Program ◽  
Typical Satellite

Owing to the lack of a good theory method to obtain the accurate equivalent elastic constants of hexagon honeycomb sandwich structure’s core, the paper analyzed mechanics performance of honeycomb sandwich structure’s core and deduced equivalent elastic constants of hexagon honeycomb sandwich structure’s core considering the wall plate expansion deformation’s effect of hexagonal cell. And also a typical satellite sandwich structure was chose as an application to analyze. The commercial finite element program ANSYS was employed to evaluate the mechanics property of hexagon honeycomb core. Numerical simulation analysis and theoretical calculation results show the formulas of equivalent elastic constants is correct and also research results of the paper provide theory basis for satellite cellular sandwich structure optimization design.

Finite Element Analysis on the Deformation of Energy-Saving Wire-Mesh Frame Wallboard

2014 ◽  
Vol 501-504 ◽  
pp. 731-735
Author(s):  
Li Zhang ◽  
Kang Li
Keyword(s):  
Finite Element ◽  
Energy Saving ◽  
Theoretical Basis ◽  
Steel Wire ◽  
Wire Mesh ◽  
Design Parameters ◽  
Element Analysis ◽  
Finite Element Program ◽  
Element Program ◽  
Influence Degree

This paper analyzes the influence degree of related design parameters of wire-mesh frame wallboard on deformation through finite element program, providing theoretical basis for the design and test of steel wire rack energy-saving wallboard.

Transferability of the Gurson Damage Model Parameters with Charpy and Tensile Tests with Different Constrain Level

2009 ◽  
Vol 65 ◽  
pp. 19-31
Author(s):  
Ruben Cuamatzi-Melendez ◽  
J.R. Yates
Keyword(s):  
Strain Rate ◽  
Damage Model ◽  
Rolling Direction ◽  
Fracture Initiation ◽  
Tensile Tests ◽  
Model Parameters ◽  
Gurson Model ◽  
Finite Element Program ◽  
Element Program ◽  
Gurson's Model

Little work has been published concerning the transferability of Gurson’s ductile damage model parameters in specimens tested at different strain rates and in the rolling direction of a Grade A ship plate steel. In order to investigate the transferability of the damage model parameters of Gurson’s model, tensile specimens with different constraint level and impact Charpy specimens were simulated to investigate the effect of the strain rate on the damage model parameters of Gurson model. The simulations were performed with the finite element program ABAQUS Explicit [1]. ABAQUS Explicit is ideally suited for the solution of complex nonlinear dynamic and quasi–static problems [2], especially those involving impact and other highly discontinuous events. ABAQUS Explicit supports not only stress–displacement analyses but also fully coupled transient dynamic temperature, displacement, acoustic and coupled acoustic–structural analyses. This makes the program very suitable for modelling fracture initiation and propagation. In ABAQUS Explicit, the element deletion technique is provided, so the damaged or dead elements are removed from the analysis once the failure criterion is locally reached. This simulates crack growth through the microstructure. It was found that the variation of the strain rate affects slightly the value of the damage model parameters of Gurson model.

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