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The change of matric suction due to heavy vehicle crossing
Publikationstyp
Conference Paper
Publikationsdatum
2014-07
Sprache
English
Author
Institut
Volume
2
Start Page
1431
End Page
1437
Citation
6th International Conference on Unsaturated Soils (UNSAT 2014)
Contribution to Conference
Scopus ID
Classical soil mechanics for unsaturated soils mainly deals with quasi static loading conditions because most laboratory tests, such as triaxial tests, are time consuming due to equilibration processes. Under natural conditions, however, cyclic and even dynamic loading of the unsaturated soil may occur with the soil response of suction and saturation being not in equilibrium in most cases. A relevant factor for the equilibration time of suction and saturation under field conditions is the soil permeability which also influences the buildup of excess pore water pressures reducing soil suction due to fast loading. This contribution deals with the change of matric suction due to cyclic loading induced by heavy vehicles passing. In two field tests, the change of matric suction due to the repeated passing of heavy vehicles has been measured dynamically with a high sampling rate. The totally different subsoils, encountered at the two test sites, allow interesting comparisons for the behaviour of unsaturated soils under dynamic loading. Generally, matric suction was temporarily reduced and exchanged by excess pore water pressures due to heavy vehicle passages. Nevertheless, the measured results in the two field tests also showed clear differences which may be attributed to the permeability of the two entirely different soils. An accumulation of pore water pressures and an increase in the degree of saturation caused by repeated cycles of loading and unloading could lead to a loss of matric suction and therefore decrease soil strength. Accordingly, it has to be discussed if a cyclic change of matric suction may be of importance for an accumulation of settlements, which is relevant for all kinds of pavements. © 2014 Taylor & Francis Group.