Experimental Investigation of Pile Installation by Vertical Jet Fluidization in Sand

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Larissa de Brum Passini ◽  
Fernando Schnaid
Keyword(s):  
Flow Rate ◽  
Initial Density ◽  
Model Tests ◽  
Laboratory Model ◽  
Embedment Depth ◽  
Pile Installation ◽  
Pile Diameter ◽  
Fluid Properties ◽  
Constitutive Parameters ◽  
Vertical Jet

The paper examines the mechanism of pile installation by vertical jet fluidization in saturated sand in order to define the constitutive parameters that control installation geometry and pile depth of embedment. A series of laboratory model tests representative of offshore torpedo piles was carried out using downwardly directed vertical water jets in both medium and dense sands. Measurements from model tests at three different scales indicate that the geometry of fluidized cavities is not influenced by the initial density of the sand and that the perturbed zone is constrained to a distance of about two pile diameters from the pile centerline during pile installation. Following the laws of dimensional analysis, an expression for the embedment of fluidized piles is derived and shows that penetration depth is a function of pile weight and geometry, fluidized water jet flow rate and velocity, as well as the soil and fluid properties. Penetration is shown to increase with increasing flow rate and pile weight and decreasing soil relative density. Although the results have to be validated by tests at larger scales to prove compatibility with the full-scale behavior, model tests indicate maximum embedment depth of the order of 50 times the pile diameter.

On the response of fluidized piles from laboratory model tests in granular soils

2014 ◽  
Vol 1 (2) ◽  
pp. 69-81 ◽  
Author(s):  
F. Schnaid ◽  
L. Passini ◽  
F. Stracke ◽  
S. Mezzomo
Keyword(s):  
Limit Equilibrium ◽  
Horizontal Stress ◽  
Design Guidelines ◽  
Model Tests ◽  
Equilibrium Analysis ◽  
Laboratory Model ◽  
Limit Equilibrium Analysis ◽  
Pile Installation ◽  
Water Jets ◽  
Constitutive Parameters

Design guidelines of foundation anchors and piles embedded in fluidized sand comprises understanding of installation processes, defining constitutive parameters and establishing analysis techniques. These fundamental aspects have been investigated by a series of laboratory model tests designed to evaluate the mechanism taking place during pile installation through the influence of downwardly-directed vertical water jets in the geometry of fluidized cavities in saturated sands. Measurements indicate fluidization geometry to be controlled by combined effects of jet velocity and the ratio of particle and jet diameters which can be conveniently expressed by the Froude number of particles. Characteristics of the fluidized zone geometry prior and after fluidization indicate considerable reduction of relative density of fluidized samples. Limit equilibrium analysis using geotechnical parameters approaching critical state provided indicative horizontal stress levels to estimate the uplift skin friction of model steel piles.

Transition of soil friction during suction pile installation

2002 ◽  
Vol 39 (5) ◽  
pp. 1118-1125 ◽  
Author(s):  
Y Cho ◽  
S Bang ◽  
T Preber
Keyword(s):  
Soil Properties ◽  
Friction Angle ◽  
Soil Strength ◽  
Model Tests ◽  
Laboratory Model ◽  
Suction Pressure ◽  
Pile Installation ◽  
Nondimensional Parameter ◽  
Pile Penetration ◽  
The Relationship

A series of laboratory model tests on the suction pile installation in sand have been conducted to obtain the relationship between the applied suction pressure inside the pile and the resulting pile penetration. The relationships have been used to estimate the mobilized soil strength during the pile installation. This reduction in the soil strength due to the applied suction pressure is described as a function of a nondimensional parameter to characterize the variation and transition of the soil strength during the pile installation. The nondimensional parameter includes all pertinent pile and soil properties that are thought to affect the behavior of the suction pile during installation.Key words: suction pile, suction pressure, mobilized effective soil friction angle.

scholarly journals Characterization of venturi injector using dimensional analysis

2019 ◽  
Vol 23 (7) ◽  
pp. 484-491 ◽  
Author(s):  
Luiz R. Sobenko ◽  
José A. Frizzone ◽  
Antonio P. de Camargo ◽  
Ezequiel Saretta ◽  
Hermes S. da Rocha
Keyword(s):  
Dimensional Analysis ◽  
Flow Rate ◽  
Injection Rate ◽  
Operating Conditions ◽  
Functional Tests ◽  
Injection Flow Rate ◽  
Injection Flow ◽  
Hydraulic Conditions ◽  
Fluid Properties ◽  
Pi Theorem

ABSTRACT Venturi injectors are commonly employed for fertigation purposes in agriculture, in which they draw fertilizer from a tank into the irrigation pipeline. The knowledge of the amount of liquid injected by this device is used to ensure an adequate fertigation operation and management. The objectives of this research were (1) to carry out functional tests of Venturi injectors following requirements stated by ISO 15873; and (2) to model the injection rate using dimensional analysis by the Buckingham Pi theorem. Four models of Venturi injectors were submitted to functional tests using clean water as motive and injected fluid. A general model for predicting injection flow rate was proposed and validated. In this model, the injection flow rate depends on the fluid properties, operating hydraulic conditions and geometrical characteristics of the Venturi injector. Another model for estimating motive flow rate as a function of inlet pressure and differential pressure was adjusted and validated for each size of Venturi injector. Finally, an example of an application was presented. The Venturi injector size was selected to fulfill the requirements of the application and the operating conditions were estimated using the proposed models.

Laboratory model tests about the sand embankment supported by piles with a cap beam

2017 ◽  
Vol 13 (1) ◽  
pp. 64-76 ◽  
Author(s):  
Zhen-Dong Cui ◽  
Qiang Yuan ◽  
Jia-Qiang Yang
Keyword(s):  
Model Tests ◽  
Laboratory Model

scholarly journals The Past and Present of Discharge Capacity Modeling for Spillways—A Swedish Perspective

Fluids ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 10 ◽  
Author(s):  
James Yang ◽  
Patrik Andreasson ◽  
Penghua Teng ◽  
Qiancheng Xie
Keyword(s):  
Discharge Capacity ◽  
Best Practice ◽  
Primary Source ◽  
Hydraulic Modeling ◽  
Model Tests ◽  
Laboratory Model ◽  
Model Quality ◽  
Cfd Simulations ◽  
Discharge Data ◽  
The Past

Most of the hydropower dams in Sweden were built before 1980. The present dam-safety guidelines have resulted in higher design floods than their spillway discharge capacity and the need for structural upgrades. This has led to renewed laboratory model tests. For some dams, even computational fluid dynamics (CFD) simulations are performed. This provides the possibility to compare the spillway discharge data between the model tests performed a few decades apart. The paper presents the hydropower development, the needs for the ongoing dam rehabilitations and the history of physical hydraulic modeling in Sweden. More than 20 spillways, both surface and bottom types, are analyzed to evaluate their discharge modeling accuracy. The past and present model tests are compared with each other and with the CFD results if available. Discrepancies do exist in the discharges between the model tests made a few decades apart. The differences fall within the range −8.3%–+11.2%. The reasons for the discrepancies are sought from several aspects. The primary source of the errors is seemingly the model construction quality and flow measurement method. The machine milling technique and 3D printing reduce the source of construction errors and improve the model quality. Results of the CFD simulations differ, at the maximum, by 3.8% from the physical tests. They are conducted without knowledge of the physical model results in advance. Following the best practice guidelines, CFD should generate results of decent accuracy for discharge prediction.

Basic Study on Mechanism of Cave-in in Road through Laboratory Model Tests

2016 ◽  
Vol 18 (5) ◽  
pp. 11-19 ◽  
Author(s):  
Gichul Kweon ◽  
Sanglok Kim ◽  
Seokwoo Hong
Keyword(s):  
Model Tests ◽  
Laboratory Model ◽  
Basic Study

A model test and numerical investigation on the shear deformation patterns of deep wall–soil–tunnel interaction

2006 ◽  
Vol 43 (12) ◽  
pp. 1306-1323 ◽  
Author(s):  
Yong-Joo Lee ◽  
Richard H Bassett
Keyword(s):  
Finite Element ◽  
Shear Deformation ◽  
Urban Areas ◽  
Shear Failure ◽  
Model Tests ◽  
Numerical Analyses ◽  
Laboratory Model ◽  
Failure Patterns ◽  
Physical Tests ◽  
Deformation Patterns

In congested urban areas, tunnel excavations have become necessary due to a lack of space. In many cases, such excavations are needed in areas adjacent to existing loaded piles. Therefore, a careful assessment of the wall–soil–tunnel interaction is required. These circumstances are relatively new, however, and only limited information is currently available. The complicated soil behaviour, particularly for the shear failure pattern between the wall and tunnel observed in both physical tests and numerical analyses, has not been clearly identified by other researchers. The authors have conducted laboratory model tests on an idealized granular medium using close-range photogrammetric techniques to measure detailed displacement patterns. The results have been compared with those from numerical analyses. This paper presents shear failure patterns for a number of geometries and shows good agreement between the physical tests and the finite element analyses.Key words: tunnel excavation, shear deformation patterns, wall–soil–tunnel interaction, model tests, photogrammetry, finite element analysis.

Numerical Simulations Concerning the Tendency of Soil Plugging in Open-Ended Steel-Piles

2009 ◽  
Author(s):  
Sascha Henke ◽  
Ju¨rgen Grabe
Keyword(s):  
Finite Element Method ◽  
Granular Soil ◽  
Soil Density ◽  
Soil Plug ◽  
Pile Installation ◽  
Pile Diameter ◽  
Rigid Pile ◽  
Steel Piles ◽  
Plug Formation

The development of soil plug inside open-ended steel-piles is investigated using Finite-Element method. The penetration of a rigid pile with various diameter into granular soil is simulated numerically to better understand the mechanisms which occur during pile installation inside the open-ended piles. The numerical results are analyzed for a better understanding of the influence of the installation method on soil plugging. The received results are compared to experimental results out of literature. Concluding, a parametric study is fulfilled to examine the role of soil density and pile diameter concerning the tendency of plug formation inside a jacked pile.

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