scholarly journals Response of tapered piles in cohesionless soil based on model tests

2010 ◽  
Vol 40 ◽  
pp. 85-92 ◽  
Author(s):  
Suman Manandhar ◽  
Noriyuki Yasufuku ◽  
Kiyoshi Omine ◽  
Taizo Kobayashi
Keyword(s):  
Skin Friction ◽  
Model Tests ◽  
High Density ◽  
Cohesionless Soil ◽  
Cohesionless Soils ◽  
Loading Test ◽  
Tapered Pile ◽  
Different Types ◽  
Steel Piles ◽  
Settlement Ratio

This paper describes model tests of different types of tapered piles in cohesionless soils. Chromium plated three steel piles, one straight and two taper-shaped piles of same length and pile tip diameters have been executed for pile loading test in a downward frictional mode. Two different types of model grounds have been prepared for the test. Relative densities of 80 % and 60 % have been modeled to penetrate piles in two different types of sands to observe the effectiveness of skin frictions of different types of piles. The response of tapered piles has shown that the skin friction has increased with increasing the tapering angle at normalized settlement ratio of 0.4. High density ground yields higher skin friction when the maximum tapered pile was penetrated. Slightly increased tapering angle of the pile affects remarkably on the skin friction with compared to conventional straight cylindrical pile even at small 0.1 settlement ratios.

Skin Friction of Taper-Shaped Piles in Sands

2009 ◽  
Author(s):  
Suman Manandhar ◽  
Noriyuki Yasufuku ◽  
Kazutaka Shomura
Keyword(s):  
Skin Friction ◽  
Confining Pressure ◽  
Load Test ◽  
Main Theme ◽  
Ground Model ◽  
Depth Of Penetration ◽  
Tapered Pile ◽  
Different Types ◽  
Pile Load Test ◽  
Free Falling

The main theme of this paper is to evaluate the skin friction and unit skin friction of different types of pile on a defined model ground. The typical silica sands were selected to make model ground at high relative densities of 80% and 60% respectively at confining pressure of 50 kPa to perform the pile load test on selected two different model ground. Model ground has been prepared by free falling of sand through sieve on the chamber to meet the required relative densities. Relative densities have acquired after evaluating desired height and area of nozzle through which dry sands fall. To fulfill the requirement, different types of tapered piles were selected to perform the pile load test. Straight and different types of tapered pile have driven in silica sands respectively at relatively high densities. Experimental results have showed that the skin friction of straight pile is considerably low with compared to tapered pile and wedging effects can be clearly seen towards the depth of penetration. In conclusion, it is clearly seen that the skin friction of tapered pile can be improved with increasing tapering angles. Higher the angle the greater the skin friction. Further, lateral stresses around the pile increases laterally during loading. Lateral stresses are increased with increase on amounts of pile expansion. The skin frictions of tapered piles have pressing effect and soil tamping effect.

Comportement de pieux d'essais instrumentés sous charge horizontale

1993 ◽  
Vol 30 (1) ◽  
pp. 1-11
Author(s):  
R. Frank ◽  
H. Zervogiannis ◽  
S. Christoulas ◽  
V. Papadopoulos ◽  
N. Kalteziotis
Keyword(s):  
Pile Foundation ◽  
Bending Moment ◽  
Standard Penetration Test ◽  
American Petroleum Institute ◽  
Full Scale ◽  
Test Method ◽  
Cohesionless Soil ◽  
Penetration Test ◽  
Cohesionless Soils ◽  
Final Design

This paper describes the behaviour of two test piles (one bored and postgrouted and one simply bored, both 31.7 m long and 0.75 m in diameter) subjected to horizontal loads. These full-scale pile tests were carried out for the actual design of the pile foundation of a pier of the Evripos cable-stayed bridge. This bridge will link the Euboea Island to mainland Greece. The two piles have already been subjected to bearing capacity tests under axial loadings. The inclinometer measurements, taken during the present tests, yielded, in particular, the deformed shape of the piles as well as the bending moments. Conclusions could be drawn for the final design of the pile foundation with respect to horizontal loadings. Furthermore, various calculation methods using p–y reaction curves for cohesionless soils have been checked: the Ménard pressuremeter method, the method of the American Petroleum Institute recommendations, and the Standard penetration test method of Christoulas. These pile tests show that simple measurements, taken on construction sites, can yield interesting results on the actual behaviour of horizontally loaded piles. Key words : pile, horizontal loading, full-scale test, horizontal loads, bending moment, subgrade reaction modulus, p–y curve, cohesionless soil, Standard penetration test, pressuremeter test.

A high-density nanowire electrode on paper for biomedical applications

RSC Advances ◽  
2015 ◽  
Vol 5 (12) ◽  
pp. 8680-8687 ◽  
Author(s):  
P. Mostafalu ◽  
S. Sonkusale
Keyword(s):  
Biomedical Applications ◽  
High Density ◽  
Different Types ◽  
Paper Substrates

Different types of nanowires made from platinum, nickel and copper are fabricated and patterned with microscale resolution on paper substrates and employed for biomedical applications.

scholarly journals Comparative Analysis of Capabilities of Different Types of Cone-Beam Tomography in an Experimental Study of Root Canals of Teeth Filled with High-Density Materials (part 2)

2021 ◽  
pp. 51-61
Author(s):  
A. Yu. Vasil'ev ◽  
V. V. Petrovskaya ◽  
E. A. Nichipor ◽  
V. G. Alpatova ◽  
N. N. Potrakhov ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Experimental Study ◽  
Cone Beam Computed Tomography ◽  
Comparative Assessment ◽  
High Density ◽  
Cone Beam ◽  
Root Canals ◽  
Different Types ◽  
Before And After ◽  
Cone Beam Tomography

During the course of this experimental study tomograms of extracted teeth were analyzed before and after filling the root canals with an endodontic material and fragments of broken metal instruments for root canal treatment. During the first stage of the experiment, untreated extracted teeth were scanned using conebeam computed tomography and microfocus cone-beam computed tomography. A comparative assessment of capabilities of the two methods of cone-beam computed tomography based on examination of untreated root canals was carried out. The second part of the study is dedicated to visualization of root canals that contain foreign high-density materials.

scholarly journals Comparative studies of the deformation techniques for the singular-drift problem in the complex Langevin method

2018 ◽  
Vol 175 ◽  
pp. 07019 ◽  
Author(s):  
Yuta Ito ◽  
Jun Nishimura
Keyword(s):  
Low Temperature ◽  
Dirac Operator ◽  
Matrix Model ◽  
Comparative Studies ◽  
Deformation Parameter ◽  
High Density ◽  
Large N ◽  
Singular Drift ◽  
Different Types ◽  
Data Points

In application of the complex Langevin method to QCD at high density and low temperature, the singular-drift problem occurs due to the appearance of near-zero eigenvalues of the Dirac operator. In order to avoid this problem, we proposed to de-form the Dirac operator in such a way that the near-zero eigenvalues do not appear and to extrapolate the deformation parameter to zero from the available data points. Here we test three different types of deformation in a simple large-N matrix model, which under-goes an SSB due to the phase of the fermion determinant, and compare them to see the consistency with one another.

Topology of Flow Separation on Three-Dimensional Bodies

1991 ◽  
Vol 44 (7) ◽  
pp. 329-345 ◽  
Author(s):  
Gary T. Chapman ◽  
Leslie A. Yates
Keyword(s):  
Skin Friction ◽  
Flow Separation ◽  
Three Dimensional ◽  
Phenomenological Approach ◽  
Three Dimensional Flow ◽  
The Past ◽  
Different Types ◽  
Primary Separation ◽  
Actual Flow

In recent years there has been extensive research on three-dimensional flow separation. There are two different approaches: the phenomenological approach and a mathematical approach using topology. These two approaches are reviewed briefly and the shortcomings of some of the past works are discussed. A comprehensive approach applicable to incompressible and compressible steady-state flows as well as incompressible unsteady flow is then presented. The approach is similar to earlier topological approaches to separation but is more complete and in some cases adds more emphasis to certain points than in the past. To assist in the classification of various types of flow, nomenclature is introduced to describe the skin-friction portraits on the surface. This method of classification is then demonstrated on several categories of flow to illustrate particular points as well as the diversity of flow separation. The categories include attached, two-dimensional separation and three different types of simple, three-dimensional primary separation, secondary separation, and compound separation. Hypothetical experiments are utilized to illustrate the topological terminology and its role in characterizing these flows. These hypothetical experiments use colored oil injected onto the surface at singular points in the skin-friction portrait. Actual flow-visualization information, if available, is used to corroborate the hypothetical examples.

Sand Displacement and Compaction around Model Friction Piles

1964 ◽  
Vol 1 (2) ◽  
pp. 81-93 ◽  
Author(s):  
E I Robinsky ◽  
C F Morrison
Keyword(s):  
Skin Friction ◽  
Strain Gage ◽  
Direct Relationship ◽  
Pile Capacity ◽  
Soil Movement ◽  
Tapered Pile

By means of radiography techniques the displacement and compaction of sand around strain gage instrumented model piles has been studied. Tests reveal a possible explanation for the low transfer of load through “skin friction” developed by a straight-sided pile, and the high transfer of load developed by the tapered pile. The limits of “visible” soil movement (displacement envelopes) have been determined for nine different pile conditions and a direct relationship has been found to exist between the magnitude of the displacement envelope and pile capacity, indicating interdependence of transfer of load through the pile point and pile wall.

Three-dimensional stability analysis for slurry-filled trench wall in cohesionless soil

1996 ◽  
Vol 33 (5) ◽  
pp. 798-808 ◽  
Author(s):  
Jiin-Song Tsai ◽  
Jia-Chyi Chang
Keyword(s):  
Stability Analysis ◽  
Stability Problem ◽  
Slip Surface ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Soil Mass ◽  
Cohesionless Soil ◽  
Cohesionless Soils ◽  
Slurry Trench ◽  
The Stability

On the basis of the limiting equilibrium and arching theory, a three-dimensional analysis is proposed for slurry-supported trenches in cohesionless soils. This analytical approach is developed by considering the trench stability problem as a vertical soil cut within a fictitious half-silo with a rough wall surronding. Arching effects are considered not only in the vertical direction but also in the horizontal direction. A shell-shaped slip surface of the sliding soil mass is defined by Mohr-Coulomb criterion. The factor of safety is defines as the ratio of the resisting force induced by slurry pressure to the horizontal force required to maintain the stability of the trench wall. Results of the proposed method have been compared with those of two existing analytical methods for a typical trench stability problem. Key words: stability analysis, slurry trench wall, cohesionless soil.

scholarly journals Impact of slopes on the lateral resistance of steel piles

2021 ◽  
Author(s):  
James Cumming
Keyword(s):  
Finite Element ◽  
Retaining Wall ◽  
Cohesionless Soils ◽  
Passive Resistance ◽  
Finite Element Software ◽  
Ground Anchors ◽  
Lateral Resistance ◽  
Steel Piles ◽  
Laterally Loaded ◽  
Soldier Pile

A soldier pile and lagging wall is one of the most common types of retaining wall. Solider pile walls develop lateral resistance through the stiffness of the piles and the passive resistance of the soil acting upon the embedded portion of the piles. Ground anchors can also be used when additional lateral resistance is required. Using Broms’ methods, a parametric study was completed to investigate the performance of laterally loaded short and long steel piles installed in a variety of cohesive and cohesionless soils. The results were compared to those generated using RocScience finite element software. RocScience software was then used to evaluate the lateral resistance of piles installed at various distances from the crest of a 2:1 slope. Finally, two soldier pile walls, to be installed within a sloping railway embankment, were designed.

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