Details
Original language | English |
---|---|
Pages (from-to) | 3-13 |
Number of pages | 11 |
Journal | Soil and Tillage Research |
Volume | 125 |
Publication status | Published - Sept 2012 |
Externally published | Yes |
Abstract
The deformation behavior of soils is strongly affected by coupled mechanical and hydraulic stresses especially under cyclic loading. Contrary to static loading tests cyclic loading caused plastic deformation increments with ongoing loading cycles even for stresses in the re-compression range associated with alterations in the hydraulic stress state. The aim of this study was to proof the interference of hydraulic properties on the mechanical deformation behavior (cyclic compressibility) depending on soil structure and cyclic loading time. Cyclic loading tests with changing boundary conditions in terms of initial matric potential, loading time and magnitude on structured and homogenized silty soil samples were performed. Furthermore, pore water pressures during cyclic loading and the air conductivity of soil cores before and after cyclic loading were measured. The results indicated differences in the stress-strain response accompanied by typical hydraulic stress regimes. These were classified into five categories representing a typical development of pore water pressures according to soil structure and loading time. Predominantly at short-time cycles a built-up of pore water pressures with increasing number of cycles occurred resulting in a high cyclic compressibility of the homogenized soil. The loss of soil strength could be linked to the beginning of partial liquefaction processes induced by heavy soil loading of 150. kPa and by a higher initial matric potential. In contrast, the less compressible structured soil showed a better internal redistribution of pore water and faster dissipation of stress-induced pore water pressures compared to the homogenized soil. Finally, the influence of soil structure plays an important role in understanding hydro-mechanical relationships, especially since the reversal of pore water pressures back to the hydraulic equilibrium state was restricted by the time between repeated loading events.
Keywords
- Compaction effects, Cyclic loading, Hydraulic stresses, Loading time, Stress-strain relations
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)
- Agronomy and Crop Science
- Agricultural and Biological Sciences(all)
- Soil Science
- Earth and Planetary Sciences(all)
- Earth-Surface Processes
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In: Soil and Tillage Research, Vol. 125, 09.2012, p. 3-13.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Effect of hydraulic and mechanical stresses on cyclic deformation processes of a structured and homogenized silty Luvic Chernozem
AU - Mordhorst, Anneka
AU - Zimmermann, Iris
AU - Peth, Stephan
AU - Horn, Rainer
PY - 2012/9
Y1 - 2012/9
N2 - The deformation behavior of soils is strongly affected by coupled mechanical and hydraulic stresses especially under cyclic loading. Contrary to static loading tests cyclic loading caused plastic deformation increments with ongoing loading cycles even for stresses in the re-compression range associated with alterations in the hydraulic stress state. The aim of this study was to proof the interference of hydraulic properties on the mechanical deformation behavior (cyclic compressibility) depending on soil structure and cyclic loading time. Cyclic loading tests with changing boundary conditions in terms of initial matric potential, loading time and magnitude on structured and homogenized silty soil samples were performed. Furthermore, pore water pressures during cyclic loading and the air conductivity of soil cores before and after cyclic loading were measured. The results indicated differences in the stress-strain response accompanied by typical hydraulic stress regimes. These were classified into five categories representing a typical development of pore water pressures according to soil structure and loading time. Predominantly at short-time cycles a built-up of pore water pressures with increasing number of cycles occurred resulting in a high cyclic compressibility of the homogenized soil. The loss of soil strength could be linked to the beginning of partial liquefaction processes induced by heavy soil loading of 150. kPa and by a higher initial matric potential. In contrast, the less compressible structured soil showed a better internal redistribution of pore water and faster dissipation of stress-induced pore water pressures compared to the homogenized soil. Finally, the influence of soil structure plays an important role in understanding hydro-mechanical relationships, especially since the reversal of pore water pressures back to the hydraulic equilibrium state was restricted by the time between repeated loading events.
AB - The deformation behavior of soils is strongly affected by coupled mechanical and hydraulic stresses especially under cyclic loading. Contrary to static loading tests cyclic loading caused plastic deformation increments with ongoing loading cycles even for stresses in the re-compression range associated with alterations in the hydraulic stress state. The aim of this study was to proof the interference of hydraulic properties on the mechanical deformation behavior (cyclic compressibility) depending on soil structure and cyclic loading time. Cyclic loading tests with changing boundary conditions in terms of initial matric potential, loading time and magnitude on structured and homogenized silty soil samples were performed. Furthermore, pore water pressures during cyclic loading and the air conductivity of soil cores before and after cyclic loading were measured. The results indicated differences in the stress-strain response accompanied by typical hydraulic stress regimes. These were classified into five categories representing a typical development of pore water pressures according to soil structure and loading time. Predominantly at short-time cycles a built-up of pore water pressures with increasing number of cycles occurred resulting in a high cyclic compressibility of the homogenized soil. The loss of soil strength could be linked to the beginning of partial liquefaction processes induced by heavy soil loading of 150. kPa and by a higher initial matric potential. In contrast, the less compressible structured soil showed a better internal redistribution of pore water and faster dissipation of stress-induced pore water pressures compared to the homogenized soil. Finally, the influence of soil structure plays an important role in understanding hydro-mechanical relationships, especially since the reversal of pore water pressures back to the hydraulic equilibrium state was restricted by the time between repeated loading events.
KW - Compaction effects
KW - Cyclic loading
KW - Hydraulic stresses
KW - Loading time
KW - Stress-strain relations
UR - http://www.scopus.com/inward/record.url?scp=84865956097&partnerID=8YFLogxK
U2 - 10.1016/j.still.2012.06.008
DO - 10.1016/j.still.2012.06.008
M3 - Article
AN - SCOPUS:84865956097
VL - 125
SP - 3
EP - 13
JO - Soil and Tillage Research
JF - Soil and Tillage Research
SN - 0167-1987
ER -