Physical and mechanical properties of sandy soil due to repeated water infiltration

Abstract

This paper presents the deformation characteristics of sandy soil specimens developed in wetting and drying processes. A series of triaxial tests was carried out on Toyoura sand and some silty sands, when the tested material is subject to wetting/drying cycles, under the constant confining pressure of 50kPa. During these processes, small cyclic loading tests were performed in order to obtain small strain stiffness of the materials. Throughout the test, volumetric, axial and radial strains were measured and the amount of water flowing in/out of the specimen was monitored. It was found that the deformation of silty sand was highly affected by the wetting/drying cycles, whereas Toyoura sand did not show noticeable changes. For silty sand, volumetric strains were developed positively throughout the first wetting process as well as the successive drying and repeated drying/wetting stages. The presence of fines appeared to play an important role in collapse behaviour of sandy soil, even though the fines content was only 3%. Small strain stiffness seemed to be also affected by the wet/dry condition, but the change in small strain stiffness could not be well explained by the change of density and suction of the material, which indicates that the internal structure of the material was altered due to the collapse occurred in the first wetting cycle. [This abstract is not included in the PDF]