The kinematic behaviour of drag anchors in sand

1996 ◽  
Vol 33 (4) ◽  
pp. 584-594 ◽  
Author(s):  
S R Neubecker ◽  
M F Randolph
Keyword(s):  
Key Words ◽  
Limit Equilibrium ◽  
Predictive Tool ◽  
Kinematic Data ◽  
Theoretical Simulation ◽  
Centrifuge Model ◽  
Essential Step ◽  
General Rules ◽  
Kinematic Behaviour ◽  
Calcareous Sands

The kinematic behaviour of drag achors during embedment in sand is examined in this paper. A series of centrifuge model anchor tests has been performed in silica and calcareous sands in which both force and kinematic data were obtained during the course of anchor embedment. In this paper, the kinematic data have been examined to determine general rules for the kinematic behaviour of a drag anchor during embedment. These rules provide an essential step towards a theoretical simulation of a complete anchor embedment history and hence a predictive tool for the ultimate holding capacity of a drag anchor. Key words: drag anchor, kinematics, sand, limit equilibrium, ultimate holding capacity.

The static equilibrium of drag anchors in sand

1996 ◽  
Vol 33 (4) ◽  
pp. 574-583 ◽  
Author(s):  
S R Neubecker ◽  
M F Randolph
Keyword(s):  
Equilibrium Solution ◽  
Limit Equilibrium ◽  
Three Dimensional ◽  
Limit Equilibrium Method ◽  
Solution Procedure ◽  
Static Equilibrium ◽  
Static Limit ◽  
Centrifuge Model ◽  
Calcareous Sands ◽  
Good Agreement

This paper examines the static equilibrium of drag anchors during embedment in sand. A limit equilibrium method is developed to allow the anchor holding capacity to be predicted given a specific anchor geometry and position relative to the free surface of the sand. The method is based on the earlier approach of Le Lievre and Tabatabaee, but is extended to include a three-dimensional soil wedge, which is consistent with experimental observation. The solution procedure is also extended to be more applicable for anchors at a preultimate stage by incorporating a force behind the anchor fluke. To calibrate the method, a series of centrifuge model anchor tests has been performed in silica and calcareous sands. The static capacity of the anchor during embedment is compared with the static limit equilibrium solution and good agreement is demonstrated. Key words: drag anchor, statics, sand, limit equilibrium, ultimate holding capacity.

APROXIMACIÓN A UNA CONCEPCIÓN TEÓRICO-METODOLÓGICA DE LOS PROCESOS DE PROFESIONALIZACIÓN PEDAGÓGICA EN LA EDUCACIÓN SUPERIOR.

2013 ◽  
Vol 1 (3) ◽  
Author(s):  
Olga Gloria Barbón Pérez ◽  
Julia Añorga Morales
Keyword(s):  
Higher Education ◽  
Key Words ◽  
Educación Superior ◽  
Comprehensive Understanding ◽  
Educacion Superior ◽  
Essential Step ◽  
Palabras Clave ◽  
Theoretical Conception ◽  
Design And Practice ◽  
Conscious Activity

El esclarecimiento de algunas de las concepciones que constituyen la base de los procesos de profesionalización pedagógica es un paso esencial para el éxito de los mismos. El presente artículo tiene como propósito aunar reflexiones que posibiliten un acercamiento hacia una concepción teórico-metodológica de los procesos de profesionalización pedagógica en la Educación Superior.El diseño y la puesta en práctica de los procesos de profesionalización pedagógica en la Educación Superior no pueden ser improvisados. Exigen, como actividad consciente, la consideración de determinados presupuestos teóricos y metodológicos que lo sustenten, y de su consideración como proceso pedagógico especial. Palabras clave: concepción teórica, concepción metodológica, profesionalización pedagógica.   ABSTRACT   Gaining on clarity concerning some of the conceptions that lie under the pedagogical professionalization processes is an essential step towards their own success. The article focuses on gathering insights that help get a more comprehensive understanding of a theoretic-methodological conception of the pedagogical professionalization processes in higher education. Both design and practice of these processes can not be improvised. They demand, as any other conscious activity, to take into account theoretical and methodological grounds and their consideration as a especial pedagogical process.   Key words: theoretical conception, methodological grounds, pedagogical professionalization.   Clarifying some of the concepts that form the basis of the processes of pedagogical professionalization is an essential step for their success.  This paper aims to join some reflections that enable the approaching to a theoretical-methodological conception of the processes of pedagogical professionalization in Higher Education.  Designing and implementing the processes of pedagogical professionalization cannot be improvised.  They demand, as a conscious activity, the consideration of certain supporting assumptions in theory and method, and their consideration as a special pedagogical process.   Keywords: theoretical conception, methodological conception, pedagogical professionalization. Recibido: Julio 2013 Aprobado: Agosto 2013

Design of reinforced fill systems over voids

1995 ◽  
Vol 32 (6) ◽  
pp. 939-945 ◽  
Author(s):  
Sherif W. Agaiby ◽  
Colin J.F.P. Jones
Keyword(s):  
Life Span ◽  
Key Words ◽  
Limit Equilibrium ◽  
Geosynthetic Reinforcement ◽  
Continuum Analysis ◽  
Limit Equilibrium Methods ◽  
Design Charts ◽  
Insight Into

Embankment fill structures are often laid on formations that may develop cavities during their life-span. The use of geosynthetic reinforcement to mitigate the consequences of the formation of such cavities provides an appealing solution to the problem. To properly analyse the problem of reinforced fill overlying cavities, the reinforcement–fill interaction has to be properly addressed and modelled for a realistic solution to be reached. Typically, this problem has been approached by researchers using limit-equilibrium methods. Limited continuum analyses results are available for the problem. This paper presents the results of a systematic parametric continuum analysis that was carried out to study this problem. The parameters that govern the behaviour of reinforced fill systems were identified and varied within their typical ranges. The objective of the study is to provide a comprehensive set of design charts that give insight into the behaviour of reinforced fill systems and highlight the effect of each of the parameters that govern this behaviour. The charts are presented in simple formats that aid the engineer to estimate the expected settlements, reinforcement tension, and width of affected zone for different conditions, as well as obtain a feel for the interaction taking place between the various elements of the system. Key words : reinforced fill, tension membranes, geosynthetics, coral formations, karstic formations, sinkholes.

Selection of operative centrifuge radius to minimize stress error in calculations

1991 ◽  
Vol 28 (1) ◽  
pp. 160-161 ◽  
Author(s):  
Brian Cooke
Keyword(s):  
Stress Distribution ◽  
Key Words ◽  
Gravity Field ◽  
Vertical Stress ◽  
Centrifugal Acceleration ◽  
Centrifuge Model ◽  
Definition Of ◽  
Centre Of Rotation ◽  
Selection Of ◽  
Stress Error

In a centrifuge model, the vertical stress distribution is nonlinear because of the variation of the model's "gravity" field with the centrifuge radius from the top to the bottom of the model. Thus in calculating the centrifugal acceleration, and hence the scale of the model, care must be taken to use the definition of centrifuge radius that minimizes the stress error in the model profile. This paper demonstrates that this optimum radius is measured from the centre of rotation to a point 0.59 times the model height from the bottom of the model. Key words: centrifuge, stress, error.

Centrifuge model tests on backfill stability

1986 ◽  
Vol 23 (3) ◽  
pp. 341-345 ◽  
Author(s):  
Robert J. Mitchell
Keyword(s):  
Key Words ◽  
Model Tests ◽  
Unconfined Compression ◽  
Cemented Sand ◽  
Mine Backfill ◽  
Geotechnical Centrifuge ◽  
Centrifuge Model ◽  
Centrifuge Tests ◽  
Behavioural Effects ◽  
Centrifuge Model Tests

The 6 m diameter, 30 g-tonne geotechnical centrifuge at Queen's University is described. Results from eight model tests, carried out on plain cemented sand samples representing mine backfills, are presented. These data show that the stable prototype backfill heights obtained from centrifuge tests exceed the failure heights predicted from unconfined compression testing by factors averaging about 1.8. This factor is explained by a combination of geometrical and behavioural effects. Still photographs of typical backfill failures in the centrifuge are included and these indicate that unacceptable ore dilution and recovery costs would be associated with the prototype failures in plain cemented tailings backfills. Key words: geotechnical centrifuge, mine backfill, model tests, cemented sand.

Multislice calculations for quasi-periodic and non-periodic objects

1990 ◽  
Vol 48 (4) ◽  
pp. 138-139
Author(s):  
R. Herrera ◽  
A. Gómez
Keyword(s):  
Electron Diffraction ◽  
Computer Simulations ◽  
Periodic Table ◽  
Amorphous Materials ◽  
Space Group ◽  
Essential Step ◽  
Shape Effects ◽  
Atomic Scattering ◽  
Diffraction Patterns ◽  
Periodic Continuation

Computer simulations of electron diffraction patterns and images are an essential step in the process of structure and/or defect elucidation. So far most programs are designed to deal specifically with crystals, requiring frequently the space group as imput parameter. In such programs the deviations from perfect periodicity are dealt with by means of “periodic continuation”.However, for many applications involving amorphous materials, quasiperiodic materials or simply crystals with defects (including finite shape effects) it is convenient to have an algorithm capable of handling non-periodicity. Our program “HeGo” is an implementation of the well known multislice equations in which no periodicity assumption is made whatsoever. The salient features of our implementation are: 1) We made Gaussian fits to the atomic scattering factors for electrons covering the whole periodic table and the ranges [0-2]Å−1 and [2-6]Å−1.

Molecular phylogenetics as a predictive tool in plant-based drug discovery in the genus Euphorbia L.

Planta Medica ◽  
2016 ◽  
Vol 81 (S 01) ◽  
pp. S1-S381 ◽  
Author(s):  
M Ernst ◽  
CH Saslis-Lagoudakis ◽  
OM Grace ◽  
N Nilsson ◽  
H Toft Simonsen ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Molecular Phylogenetics ◽  
Predictive Tool
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