scholarly journals Analysis of model helical piles subjected to axial compression

2020 ◽  
Vol 72 (09) ◽  
pp. 759-769
Keyword(s):  
Axial Compression ◽  
Model Tests ◽  
Numerical Analyses ◽  
Design Parameters ◽  
Laboratory Model ◽  
Good Correspondence ◽  
Plate Spacing ◽  
Plate Number ◽  
Helical Piles ◽  
Theoretical Results

An investigation into axial compression capacity of single helical piles placed in dry sand through laboratory model tests and numerical analyses is presented. The compressive bearing capacities were compared with existing theoretical results given in the literature. Laboratory model tests were performed to determine some design parameters of helical piles such as the plate number, plate diameter, and plate spacing. A good correspondence between experimental, numerical, and theoretical results was established.

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.

scholarly journals Research Results of the Potato Digger Technological Process

2018 ◽  
Vol 12 (5) ◽  
pp. 14-19 ◽  
Author(s):  
V. M. Alakin ◽  
G. S. Nikitin
Keyword(s):  
Design Parameters ◽  
Operating Speed ◽  
Working Process ◽  
Projectile Motion ◽  
Operating Process ◽  
Cutoff Angle ◽  
The Stability ◽  
Theoretical Results ◽  
Optimum Working

A potato digger equipped with a four­bladed beater operating in connection with rotary separating surface has low material and energy consumption, higher separating efficiency, as well as lower degree of tuber damaging. The potato digger design should include a four­bladed intake­and­feed beater to prevent potato heap transportation faults in front of the first section. (Research purpose) Increasing the technological and economic efficiency of a potato digging­and­ separating unit through the determination of the optimum values of the design parameters and operating process of the intake­and­feed beater. (Materials and methods) the authors have made an overview of general principles of ensuring the stability of the potato heap movement provided by the four­bladed intake­and­feed beater. The dependency of the minimum beater speed on the operating speed of the potato digger has been found to exclude a probability of its overloading. The methodology of calculating the potato heap velocity and the cutoff angle between the material and the beater blades has been worked out by analyzing potato heap lifting to the upper points of the working units of the rotary separator’s first section. Operating speed of the beater has been determined through the differential equation for the speed of a potato heap moving along the blade surface. (Results and discussion) Preliminary potato heap speed and cutoff angle have been found through the equation of dynamics describing the projectile motion of an object thrown at an angle. The operating values of the angles are dependent on the potato digger working speed and can be selected from the triangle of speeds. The authors have determined the dependence of the optimal beater speed on the working speed of a potato digger. Its value should exceed the minimum speed of the beater. (Conclusions) Theoretical results allow proposing the best design features and optimum working process parameters of a four­bladed beater receiving a potato heap, transporting it and lifting on the rotary separating surface.

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

Calculation of Meshing Efficiency of Helical Gear Based on Double Integral Method

2016 ◽  
Vol 693 ◽  
pp. 458-462
Author(s):  
D.G. Chang ◽  
F. Shu ◽  
X.B. Chen ◽  
Y.J. Zou
Keyword(s):  
Experimental Data ◽  
Coordinate System ◽  
Theoretical Basis ◽  
Integral Method ◽  
Helical Gear ◽  
Design Parameters ◽  
Double Integral ◽  
Rectangular Coordinate System ◽  
Helical Gears ◽  
Theoretical Results

The meshing efficiency of helical gear transmission is calculated by using the method of double integral. The external involute helical gear meshing is taken and the model of helical gears is simplified by the idea of differential. The instantaneous efficiency equation of a meshing point is derived, and further more the rectangular coordinate system of meshing zone of helical gears is established. The average meshing efficiency of helical gears is achieved by using double integral method. Then, the influence of design parameters is studied and the efficiency formula is verified by comparing the theoretical results with relevant experimental data, which can provide a theoretical basis for decide the design parameters.

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

Stability analysis of a copper tailings dam via laboratory model tests: A Chinese case study

2011 ◽  
Vol 24 (2) ◽  
pp. 122-130 ◽  
Author(s):  
Guangzhi Yin ◽  
Guangzhi Li ◽  
Zuoan Wei ◽  
Ling Wan ◽  
Guohong Shui ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Model Tests ◽  
Laboratory Model ◽  
Tailings Dam ◽  
Copper Tailings ◽  
Chinese Case

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.

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