Unsaturated Volcanic Tephra and Its Effect for Soil Movement in El Salvador

José Alexander Chávez Hernández; José Alexander Chávez Hernández; Jiři Šebesta; Lubomir Kopecky; Reynaldo López Landaverde; José Landaverde

doi:doi:10.11648/j.earth.20130202.15

Unsaturated Volcanic Tephra and Its Effect for Soil Movement in El Salvador

José Alexander Chávez Hernández, José Alexander Chávez Hernández, Jiři Šebesta, Lubomir Kopecky, Reynaldo López Landaverde, José Landaverde

Published in Earth Sciences (Volume 2, Issue 2)

Published: 2 April 2013

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Abstract

In El Salvador during the rainy season or when major earthquakes affect the area, processes like mass move-ments, liquefaction, erosion and floods affect the territory leaving environmental, social and economic damages. The vol-canic tephras called "Tierra Blanca Joven" (TBJ) which is a product of the last plinian eruption of the Ilopango Caldera are the more problematic region in the Metropolitan Area of San Salvador. In El Salvador during the summer and rainy season the groundwater level remains low in most of the areas, this means that the soils in the country are unsaturated and there are capillary forces that act on the soil structure making that an “apparent cohesion” (suction) improve the strength of the soil; this circumstance makes that the slopes are almost vertical and temporally stable, but will collapse when wetted or during seismic events. To that problematic is possible to add that the majority of the water pipelines are in bad condition and when they fail is possible to expect the collapse of entire streets or houses. Wetting of the soil is likely to occur following construction development, because evaporation is reduced by covering the ground surface with a structure. For unsaturated soils the use of two independent stress variables: net stress and suction are needed. Suction values of TBJ “G” unit of the proximal facie were obtained using pressure plate, tensiometer and filter paper to obtain a Soil-Water Retention Curve (SWRC); the use of this curve into finite elements software can help to obtain the shear strength and permeability properties. For monitoring, the use of Quickdraw tensiometers (suction) and TMS3 (soil moisture content) is proposed, because it could be a way to build a field methodology for early warning system for the slopes for urban planning and risk assessment.

Published in	Earth Sciences (Volume 2, Issue 2)
DOI	10.11648/j.earth.20130202.15
Page(s)	58-65
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2013. Published by Science Publishing Group

Keywords

Tierra Blanca Joven, Erosion, Mass Movement, Unsaturated, Suction, Tensiometer, Soil Moisture Sensor

References

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APA Style

José Alexander Chávez Hernández, José Alexander Chávez Hernández, Jiři Šebesta, Lubomir Kopecky, Reynaldo López Landaverde, et al. (2013). Unsaturated Volcanic Tephra and Its Effect for Soil Movement in El Salvador. Earth Sciences, 2(2), 58-65. https://doi.org/10.11648/j.earth.20130202.15

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ACS Style

José Alexander Chávez Hernández; José Alexander Chávez Hernández; Jiři Šebesta; Lubomir Kopecky; Reynaldo López Landaverde, et al. Unsaturated Volcanic Tephra and Its Effect for Soil Movement in El Salvador. Earth Sci. 2013, 2(2), 58-65. doi: 10.11648/j.earth.20130202.15

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AMA Style

José Alexander Chávez Hernández, José Alexander Chávez Hernández, Jiři Šebesta, Lubomir Kopecky, Reynaldo López Landaverde, et al. Unsaturated Volcanic Tephra and Its Effect for Soil Movement in El Salvador. Earth Sci. 2013;2(2):58-65. doi: 10.11648/j.earth.20130202.15

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@article{10.11648/j.earth.20130202.15,
  author = {José Alexander Chávez Hernández and José Alexander Chávez Hernández and Jiři Šebesta and Lubomir Kopecky and Reynaldo López Landaverde and José Landaverde},
  title = {Unsaturated Volcanic Tephra and Its Effect for Soil Movement in El Salvador},
  journal = {Earth Sciences},
  volume = {2},
  number = {2},
  pages = {58-65},
  doi = {10.11648/j.earth.20130202.15},
  url = {https://doi.org/10.11648/j.earth.20130202.15},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.earth.20130202.15},
  abstract = {In El Salvador during the rainy season or when major earthquakes affect the area, processes like mass move-ments, liquefaction, erosion and floods affect the territory leaving environmental, social and economic damages. The vol-canic tephras called "Tierra Blanca Joven" (TBJ) which is a product of the last plinian eruption of the Ilopango Caldera are the more problematic region in the Metropolitan Area of San Salvador. In El Salvador during the summer and rainy season the groundwater level remains low in most of the areas, this means that the soils in the country are unsaturated and there are capillary forces that act on the soil structure making that an “apparent cohesion” (suction) improve the strength of the soil; this circumstance makes that the slopes are almost vertical and temporally stable, but will collapse when wetted or during seismic events. To that problematic is possible to add that the majority of the water pipelines are in bad condition and when they fail is possible to expect the collapse of entire streets or houses. Wetting of the soil is likely to occur following construction development, because evaporation is reduced by covering the ground surface with a structure. For unsaturated soils the use of two independent stress variables: net stress and suction are needed. Suction values of TBJ “G” unit of the proximal facie were obtained using pressure plate, tensiometer and filter paper to obtain a Soil-Water Retention Curve (SWRC); the use of this curve into finite elements software can help to obtain the shear strength and permeability properties. For monitoring, the use of Quickdraw tensiometers (suction) and TMS3 (soil moisture content) is proposed, because it could be a way to build a field methodology for early warning system for the slopes for urban planning and risk assessment.},
 year = {2013}
}

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TY  - JOUR
T1  - Unsaturated Volcanic Tephra and Its Effect for Soil Movement in El Salvador
AU  - José Alexander Chávez Hernández
AU  - José Alexander Chávez Hernández
AU  - Jiři Šebesta
AU  - Lubomir Kopecky
AU  - Reynaldo López Landaverde
AU  - José Landaverde
Y1  - 2013/04/02
PY  - 2013
N1  - https://doi.org/10.11648/j.earth.20130202.15
DO  - 10.11648/j.earth.20130202.15
T2  - Earth Sciences
JF  - Earth Sciences
JO  - Earth Sciences
SP  - 58
EP  - 65
PB  - Science Publishing Group
SN  - 2328-5982
UR  - https://doi.org/10.11648/j.earth.20130202.15
AB  - In El Salvador during the rainy season or when major earthquakes affect the area, processes like mass move-ments, liquefaction, erosion and floods affect the territory leaving environmental, social and economic damages. The vol-canic tephras called "Tierra Blanca Joven" (TBJ) which is a product of the last plinian eruption of the Ilopango Caldera are the more problematic region in the Metropolitan Area of San Salvador. In El Salvador during the summer and rainy season the groundwater level remains low in most of the areas, this means that the soils in the country are unsaturated and there are capillary forces that act on the soil structure making that an “apparent cohesion” (suction) improve the strength of the soil; this circumstance makes that the slopes are almost vertical and temporally stable, but will collapse when wetted or during seismic events. To that problematic is possible to add that the majority of the water pipelines are in bad condition and when they fail is possible to expect the collapse of entire streets or houses. Wetting of the soil is likely to occur following construction development, because evaporation is reduced by covering the ground surface with a structure. For unsaturated soils the use of two independent stress variables: net stress and suction are needed. Suction values of TBJ “G” unit of the proximal facie were obtained using pressure plate, tensiometer and filter paper to obtain a Soil-Water Retention Curve (SWRC); the use of this curve into finite elements software can help to obtain the shear strength and permeability properties. For monitoring, the use of Quickdraw tensiometers (suction) and TMS3 (soil moisture content) is proposed, because it could be a way to build a field methodology for early warning system for the slopes for urban planning and risk assessment.
VL  - 2
IS  - 2
ER  -

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Author Information

José Alexander Chávez Hernández

Department of Geotechnics, Faculty of Civil Engineering, Czech Technical University in Prague, ?VUT, Prague, Czech Republic
José Alexander Chávez Hernández

Department of Geotechnics, Faculty of Civil Engineering, Czech Technical University in Prague, ?VUT, Prague, Czech Republic
Jiři Šebesta
Lubomir Kopecky

Department of Mechanics, Faculty of Civil Engineering, ?VUT, Prague, Czech Republic
Reynaldo López Landaverde

Departamento de Recursos Naturales y Medio Ambiente, Facultad de Ciencias Agronómicas, Universidad de El Salvador, San Salvador, El Salvador
José Landaverde

Departamento de Geotecnia, Escuela de Civil, Facultad de Ingeniería y Arquitectura, Universidad de El Salvador, San Salvador, El Salvador

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APA Style

José Alexander Chávez Hernández, José Alexander Chávez Hernández, Jiři Šebesta, Lubomir Kopecky, Reynaldo López Landaverde, et al. (2013). Unsaturated Volcanic Tephra and Its Effect for Soil Movement in El Salvador. Earth Sciences, 2(2), 58-65. https://doi.org/10.11648/j.earth.20130202.15

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ACS Style

José Alexander Chávez Hernández; José Alexander Chávez Hernández; Jiři Šebesta; Lubomir Kopecky; Reynaldo López Landaverde, et al. Unsaturated Volcanic Tephra and Its Effect for Soil Movement in El Salvador. Earth Sci. 2013, 2(2), 58-65. doi: 10.11648/j.earth.20130202.15

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AMA Style

José Alexander Chávez Hernández, José Alexander Chávez Hernández, Jiři Šebesta, Lubomir Kopecky, Reynaldo López Landaverde, et al. Unsaturated Volcanic Tephra and Its Effect for Soil Movement in El Salvador. Earth Sci. 2013;2(2):58-65. doi: 10.11648/j.earth.20130202.15

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@article{10.11648/j.earth.20130202.15,
  author = {José Alexander Chávez Hernández and José Alexander Chávez Hernández and Jiři Šebesta and Lubomir Kopecky and Reynaldo López Landaverde and José Landaverde},
  title = {Unsaturated Volcanic Tephra and Its Effect for Soil Movement in El Salvador},
  journal = {Earth Sciences},
  volume = {2},
  number = {2},
  pages = {58-65},
  doi = {10.11648/j.earth.20130202.15},
  url = {https://doi.org/10.11648/j.earth.20130202.15},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.earth.20130202.15},
  abstract = {In El Salvador during the rainy season or when major earthquakes affect the area, processes like mass move-ments, liquefaction, erosion and floods affect the territory leaving environmental, social and economic damages. The vol-canic tephras called "Tierra Blanca Joven" (TBJ) which is a product of the last plinian eruption of the Ilopango Caldera are the more problematic region in the Metropolitan Area of San Salvador. In El Salvador during the summer and rainy season the groundwater level remains low in most of the areas, this means that the soils in the country are unsaturated and there are capillary forces that act on the soil structure making that an “apparent cohesion” (suction) improve the strength of the soil; this circumstance makes that the slopes are almost vertical and temporally stable, but will collapse when wetted or during seismic events. To that problematic is possible to add that the majority of the water pipelines are in bad condition and when they fail is possible to expect the collapse of entire streets or houses. Wetting of the soil is likely to occur following construction development, because evaporation is reduced by covering the ground surface with a structure. For unsaturated soils the use of two independent stress variables: net stress and suction are needed. Suction values of TBJ “G” unit of the proximal facie were obtained using pressure plate, tensiometer and filter paper to obtain a Soil-Water Retention Curve (SWRC); the use of this curve into finite elements software can help to obtain the shear strength and permeability properties. For monitoring, the use of Quickdraw tensiometers (suction) and TMS3 (soil moisture content) is proposed, because it could be a way to build a field methodology for early warning system for the slopes for urban planning and risk assessment.},
 year = {2013}
}

Copy | Download

TY  - JOUR
T1  - Unsaturated Volcanic Tephra and Its Effect for Soil Movement in El Salvador
AU  - José Alexander Chávez Hernández
AU  - José Alexander Chávez Hernández
AU  - Jiři Šebesta
AU  - Lubomir Kopecky
AU  - Reynaldo López Landaverde
AU  - José Landaverde
Y1  - 2013/04/02
PY  - 2013
N1  - https://doi.org/10.11648/j.earth.20130202.15
DO  - 10.11648/j.earth.20130202.15
T2  - Earth Sciences
JF  - Earth Sciences
JO  - Earth Sciences
SP  - 58
EP  - 65
PB  - Science Publishing Group
SN  - 2328-5982
UR  - https://doi.org/10.11648/j.earth.20130202.15
AB  - In El Salvador during the rainy season or when major earthquakes affect the area, processes like mass move-ments, liquefaction, erosion and floods affect the territory leaving environmental, social and economic damages. The vol-canic tephras called "Tierra Blanca Joven" (TBJ) which is a product of the last plinian eruption of the Ilopango Caldera are the more problematic region in the Metropolitan Area of San Salvador. In El Salvador during the summer and rainy season the groundwater level remains low in most of the areas, this means that the soils in the country are unsaturated and there are capillary forces that act on the soil structure making that an “apparent cohesion” (suction) improve the strength of the soil; this circumstance makes that the slopes are almost vertical and temporally stable, but will collapse when wetted or during seismic events. To that problematic is possible to add that the majority of the water pipelines are in bad condition and when they fail is possible to expect the collapse of entire streets or houses. Wetting of the soil is likely to occur following construction development, because evaporation is reduced by covering the ground surface with a structure. For unsaturated soils the use of two independent stress variables: net stress and suction are needed. Suction values of TBJ “G” unit of the proximal facie were obtained using pressure plate, tensiometer and filter paper to obtain a Soil-Water Retention Curve (SWRC); the use of this curve into finite elements software can help to obtain the shear strength and permeability properties. For monitoring, the use of Quickdraw tensiometers (suction) and TMS3 (soil moisture content) is proposed, because it could be a way to build a field methodology for early warning system for the slopes for urban planning and risk assessment.
VL  - 2
IS  - 2
ER  -

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