Cyclic deformation of granular material subjected to moving-wheel loads

This paper describes a new testing method to examine the mechanical behavior of railroad ballast subjected to repeated train passages on ballasted track. Two types of cyclic loading tests, namely a single-point loading test and a moving-wheel loading test, were performed with small-scale models of ballasted track. Next, a “multi-ring shear apparatus” was developed as a type of torsional simple shear apparatus, and the applicability of a newly proposed multi-ring shear test to an element test of railroad ballast subjected to moving-wheel loads was examined by comparing the results of multi-ring shear tests with those of small-scale model tests. As a result, it was recognized that cumulative strain obtained from multi-ring shear tests is almost equivalent to the one derived from small-scale model tests. Moreover, it was revealed that the difference between loading methods has a considerable influence on the cyclic plastic deformation of railroad ballast because settlement in a moving-wheel loading test was much larger than the one in a single-point loading test. These results lead to the conclusion that a multi-ring shear test has an excellent applicability to the estimation of deformation behavior of granular materials subjected to moving-wheel loads.

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Experimental Study on Effect of Disc Form on Soil Failure State of Expanded Piles under Horizontal Force

Materials Science Forum ◽

10.4028/www.scientific.net/msf.980.291 ◽

2020 ◽

Vol 980 ◽

pp. 291-300

Author(s):

Yong Mei Qian ◽

Yu Chen Song ◽

Yu Jie Jin ◽

Thato Molomo Pius Moshoeshoe

Keyword(s):

Test Method ◽

Scale Model ◽

Small Scale ◽

Horizontal Force ◽

Paper Test ◽

Loading Test ◽

Undisturbed Soil ◽

Soil Failure ◽

Failure State ◽

Small Scale Model

In this paper, test method of half-section small-scale model with indoor undisturbed soil is used to study the effect of difference disc forms on bearing mechanism of concrete disc piles and soil failure state around piles under horizontal force. The model piles with different disc cross-section forms were designed under the condition of undisturbed soil, and loading test was carried out to analyze soil failure state around the pile. The results show that: under the action of horizontal force, soil around the pile is cracked along the midline; asymmetric bearing disc is more reasonable than symmetrical bearing disc. The minimum load difference between the disc end fillet and the disc tip fillet is less than 5%. The curved end of bearing disc has little effect on the horizontal bearing capacity of concrete expanded disc pile.

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STUDY OF POSITIVE PRESSURE VENTILATION IN ROOM FIRES USING A SMALL-SCALE MODEL

Heat Transfer Research ◽

10.1615/heattransres.2018025564 ◽

2019 ◽

Vol 50 (3) ◽

pp. 243-261

Author(s):

T. Y. Yeung ◽

W. K. Chow

Keyword(s):

Positive Pressure Ventilation ◽

Scale Model ◽

Positive Pressure ◽

Small Scale ◽

Room Fires ◽

Small Scale Model

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Wave Energy Hyperbaric Device for Electricity Production

Volume 5: Ocean Space Utilization; Polar and Arctic Sciences and Technology; The Robert Dean Symposium on Coastal and Ocean Engineering; Special Symposium on Offshore Renewable Energy ◽

10.1115/omae2007-29743 ◽

2007 ◽

Cited By ~ 7

Author(s):

Segen F. Estefen ◽

Paulo Roberto da Costa ◽

Eliab Ricarte ◽

Marcelo M. Pinheiro

Keyword(s):

Power Generation ◽

Wave Energy ◽

Experimental Results ◽

Electricity Production ◽

Scale Model ◽

Small Scale ◽

Regular Waves ◽

Hyperbaric Chamber ◽

Small Scale Model

Wave energy is a renewable and non-polluting source and its use is being studied in different countries. The paper presents an overview on the harnessing of energy from waves and the activities associated with setting up a plant for extracting energy from waves in Port of Pecem, on the coast of Ceara State, Brazil. The technology employed is based on storing water under pressure in a hyperbaric chamber, from which a controlled jet of water drives a standard turbine. The wave resource at the proposed location is presented in terms of statistics data obtained from previous monitoring. The device components are described and small scale model tested under regular waves representatives of the installation region. Based on the experimental results values of prescribed pressures are identified in order to optimize the power generation.

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