Assessing surface seals of soils on slopes

Past research has observed that infiltration on surface soil which is subjected to frequent rainfall does not start as soon as precipitation begins. This phenomenon is attributed to the formation of a thin dense layer called surface seal on the surface soil. The surface seal is created by interac...

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Bibliographic Details
Main Author: Liu, Chenying
Other Authors: Leong Eng Choon
Format: Final Year Project (FYP)
Language:English
Published: 2017
Subjects:
Online Access:http://hdl.handle.net/10356/71021
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author Liu, Chenying
author2 Leong Eng Choon
author_facet Leong Eng Choon
Liu, Chenying
author_sort Liu, Chenying
collection NTU
description Past research has observed that infiltration on surface soil which is subjected to frequent rainfall does not start as soon as precipitation begins. This phenomenon is attributed to the formation of a thin dense layer called surface seal on the surface soil. The surface seal is created by interaction forces between water and soil particles such as compaction, attachment, dispersion and so on. Surface seal formation plays a significant role in the process of slope erosion. The presence of the surface seal leads to the decrease of infiltration and increase in surface runoff which greatly enhances the possibility of erosion occurring. The objective of this project is to ascertain the existence of surface seal on the surface of a residual soil slope by analyzing and summarizing data and parameters obtained from field tests and laboratory experiments which were conducted on the surface soils. Infiltrometer tests were carried out at twelve locations at the crest, the face and the toe of a residual soil slope. Quick draw tensiometer test was also performed at the same location to provide corroboration of infiltration rate. Flexible wall falling-head permeability test was used to determine the saturated permeability of the soil in the laboratory. Pressure plate test was used to determine the soil-water characteristic curve (SWCC) of the soil samples. Specific gravity and hydrometer test was used to obtain α and n parameters in the van Genuchten SWCC equation. Permeability differences were used to determine the presence of a surface seal. The conclusion is drawn that surface seal appears to exist only at the crest of the slope. Van Genuchten parameters obtained from soil textures are consistent with those estimated from SWCC. Recommendations for future research are given at the end of the report.
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format Final Year Project (FYP)
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spelling ntu-10356/710212023-03-03T17:19:15Z Assessing surface seals of soils on slopes Liu, Chenying Leong Eng Choon School of Civil and Environmental Engineering DRNTU::Engineering::Civil engineering::Geotechnical Past research has observed that infiltration on surface soil which is subjected to frequent rainfall does not start as soon as precipitation begins. This phenomenon is attributed to the formation of a thin dense layer called surface seal on the surface soil. The surface seal is created by interaction forces between water and soil particles such as compaction, attachment, dispersion and so on. Surface seal formation plays a significant role in the process of slope erosion. The presence of the surface seal leads to the decrease of infiltration and increase in surface runoff which greatly enhances the possibility of erosion occurring. The objective of this project is to ascertain the existence of surface seal on the surface of a residual soil slope by analyzing and summarizing data and parameters obtained from field tests and laboratory experiments which were conducted on the surface soils. Infiltrometer tests were carried out at twelve locations at the crest, the face and the toe of a residual soil slope. Quick draw tensiometer test was also performed at the same location to provide corroboration of infiltration rate. Flexible wall falling-head permeability test was used to determine the saturated permeability of the soil in the laboratory. Pressure plate test was used to determine the soil-water characteristic curve (SWCC) of the soil samples. Specific gravity and hydrometer test was used to obtain α and n parameters in the van Genuchten SWCC equation. Permeability differences were used to determine the presence of a surface seal. The conclusion is drawn that surface seal appears to exist only at the crest of the slope. Van Genuchten parameters obtained from soil textures are consistent with those estimated from SWCC. Recommendations for future research are given at the end of the report. Bachelor of Engineering (Civil) 2017-05-12T08:06:17Z 2017-05-12T08:06:17Z 2017 Final Year Project (FYP) http://hdl.handle.net/10356/71021 en Nanyang Technological University 111 p. application/pdf
spellingShingle DRNTU::Engineering::Civil engineering::Geotechnical
Liu, Chenying
Assessing surface seals of soils on slopes
title Assessing surface seals of soils on slopes
title_full Assessing surface seals of soils on slopes
title_fullStr Assessing surface seals of soils on slopes
title_full_unstemmed Assessing surface seals of soils on slopes
title_short Assessing surface seals of soils on slopes
title_sort assessing surface seals of soils on slopes
topic DRNTU::Engineering::Civil engineering::Geotechnical
url http://hdl.handle.net/10356/71021
work_keys_str_mv AT liuchenying assessingsurfacesealsofsoilsonslopes