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" Experimental Study of Recession of Predominantly Sandy Bluffs and the Influence of Soil Strength on Erosion Processes "
Ghazian Arabi, Mahsa
Farhadzadeh, Ali
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Latin Dissertation
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| Language of Document
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English
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| Record Number
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1107662
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| Doc. No
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TLpq2452943541
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| Main Entry
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Farhadzadeh, Ali
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Ghazian Arabi, Mahsa
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| Title & Author
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Experimental Study of Recession of Predominantly Sandy Bluffs and the Influence of Soil Strength on Erosion Processes\ Ghazian Arabi, MahsaFarhadzadeh, Ali
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| College
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State University of New York at Stony Brook
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| Date
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2020
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| student score
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2020
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| Degree
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Ph.D. C.E.
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| Page No
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107
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| Abstract
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This research consists of two components: (1) Quantifying the erodibility of low fine content soils of various mechanical properties, and (2) Understanding the recession of beach-bluff systems of varying soil properties under breaking wave and surge actions. For the first component, the initiation of erosion tests were conducted on soil mixtures, with five different fine contents, two relative densities, and two initial water contents, under unidirectional steady current condition. The results indicate that the critical shear stress increased with the fine content. Also, the samples with an optimum initial water content demonstrated a higher erosion resistance than those with an initial water content dry of optimum. Furthermore, the relative density drastically reduced the soil erodibility such that the critical shear stress remained relatively insensitive to the soil composition for the denser soils. The higher relative density combined with the optimum initial water content led to the greatest resistance against erosion. An empirical relationship was developed by modifying the critical Shields parameter to include soil composition and the other characteristics. The second component included wave flume experiments on the beach and bluff systems with the constituent materials having the same characteristics as those used in the erodibility tests. The experiments were designed to assess the effects of fine content, relative density, and initial water content, on the erosion and recession of the beach-bluff system. Hence, the beach and bluff were constructed in the flume and exposed to varying water levels and waves. The analysis of the profile data, extracted from the images using image processing techniques, indicate that the increase of the fine content significantly reduced the beach erosion and bluff recession rates. The dominant failure mode for bluffs composed of the looser material and those containing lower amount of fine-grained material was the shear failure. On the other hand, for the bluffs with a higher fine content, and those with the denser soil, the failure mode was the tensile failure. The analysis resulted in the establishment of an empirical relationship for the recession rate as a function of fine content, relative density, and water content.
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Civil engineering
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Environmental science
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Soil sciences
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