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Measuring the angle of repose of granular systems using hollow cylinders

Liu, Zhichao (2011) Measuring the angle of repose of granular systems using hollow cylinders. Master's Thesis, University of Pittsburgh.

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    Abstract

    The angle of repose of granular systems was investigated using hollow cylinders of different diameters and lengths and bases of different degree of roughness. The cylinders contained homogeneous samples of sand and gravel as well mixtures of sand and gravel with the sand either thoroughly mixed with the gravel or in layered systems. From the laboratory experiments, the following conclusions can be made: (a) the angle of repose of the granular systems was influenced by the degree of roughness of the base on which the grains came to rest. The rougher the base was, the higher was the angle of repose; (b) the mode of failure of the conical pile of grains was different depending if the base was rough or smooth. For a rough base, the failure took place on the face of the conical shape. For a smooth base, the failure took place at the base of the conical shape; (c) the lifting velocities of the cylinders were varied between a slow velocity (2 to 3 cm/sec) and a high velocity (7 to 8 cm/sec). The angle of repose was found to be smaller when the high velocity of cylinder lifting was used regardless of the bases¡¯ roughness; (d) the angle of repose was found to decrease in value as the amount of material contained in the cylinders increased in value; (e) the experiments on mixtures of sand and gravel indicated that their angle of repose decreased in value as the percentage of sand in the mixture increased in value; (f) the experiments on layered granular systems (gravel on top of sand) indicated that, regardless of the lifting velocity of the cylinders, the angle of repose of the layered systems decreased in value as the height of the sand layer in the composite increased in value; and (g) the results of the tests helped to explain the angle of repose found in real rock slopes.


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    Item Type: University of Pittsburgh ETD
    ETD Committee:
    ETD Committee TypeCommittee MemberEmail
    Committee ChairVallejo, Luis E.vallejo@pitt.edu
    Committee MemberIannacchione, Anthonyati2@pitt.edu
    Committee MemberGarcia, C. Isaaccigarcia@pitt.edu
    Title: Measuring the angle of repose of granular systems using hollow cylinders
    Status: Unpublished
    Abstract: The angle of repose of granular systems was investigated using hollow cylinders of different diameters and lengths and bases of different degree of roughness. The cylinders contained homogeneous samples of sand and gravel as well mixtures of sand and gravel with the sand either thoroughly mixed with the gravel or in layered systems. From the laboratory experiments, the following conclusions can be made: (a) the angle of repose of the granular systems was influenced by the degree of roughness of the base on which the grains came to rest. The rougher the base was, the higher was the angle of repose; (b) the mode of failure of the conical pile of grains was different depending if the base was rough or smooth. For a rough base, the failure took place on the face of the conical shape. For a smooth base, the failure took place at the base of the conical shape; (c) the lifting velocities of the cylinders were varied between a slow velocity (2 to 3 cm/sec) and a high velocity (7 to 8 cm/sec). The angle of repose was found to be smaller when the high velocity of cylinder lifting was used regardless of the bases¡¯ roughness; (d) the angle of repose was found to decrease in value as the amount of material contained in the cylinders increased in value; (e) the experiments on mixtures of sand and gravel indicated that their angle of repose decreased in value as the percentage of sand in the mixture increased in value; (f) the experiments on layered granular systems (gravel on top of sand) indicated that, regardless of the lifting velocity of the cylinders, the angle of repose of the layered systems decreased in value as the height of the sand layer in the composite increased in value; and (g) the results of the tests helped to explain the angle of repose found in real rock slopes.
    Date: 24 June 2011
    Date Type: Completion
    Defense Date: 22 February 2011
    Approval Date: 24 June 2011
    Submission Date: 24 February 2011
    Access Restriction: No restriction; Release the ETD for access worldwide immediately.
    Patent pending: No
    Institution: University of Pittsburgh
    Thesis Type: Master's Thesis
    Refereed: Yes
    Degree: MSCE - Master of Science in Civil Engineering
    URN: etd-02242011-215113
    Uncontrolled Keywords: granular systems; angle of repose; cylinder experiments
    Schools and Programs: Swanson School of Engineering > Civil and Environmental Engineering
    Date Deposited: 10 Nov 2011 14:31
    Last Modified: 22 Feb 2012 13:21
    Other ID: http://etd.library.pitt.edu/ETD/available/etd-02242011-215113/, etd-02242011-215113

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