Effect of Grain Size Distribution of Sandy Soil on Shearing Behaviors at Soil–Structure Interface

Abstract

For the geotechnical construction and maintenance, assessing the shearing behavior at the soil-structure interface is significant. This study presents an experimental investigation about the effect of the grain size distribution of a sandy soil on the shearing behaviors at the soil-structure interface, using a modified direct shear apparatus. Five soil samples with different coefficients of uniformity were prepared.The normalized roughness of the structure surface (the ratio between the maximum roughness of the structure plate and the mean grain size of the soil), the relative density, the maximum, the mean and the minimum grain sizes of all samples were controlled the same. During the tests, the shear force, the shear displacement and the vertical displacement were monitored. The results show that at a given shear displacement and normal stress, the sample with lower coefficient of uniformity Cu presents higher shear stress and more pronounced dilative behavior. The increase of Cu leads to the decrease of the friction angle for the soil-structure interface (at both peak and ultimate states) and the decrease of the maximum vertical deformation of the soil sample during the shearing process. As Cu increases, the main force chain at the soil-structure interface turns from the contact between the coarser grains to that mainly formed by the finer grains, resulting in the decrease of the shearing resistance. In comparison with the previous relevant studies, the decreasing trend of the friction angle with the increase of Cu is strongly supported.

Effect of Grain Size Distribution on Drained Shear Behavior of Poorly Graded Sand

“…When the fines content is less than the TFC (50 %), with lower Cu, sand presents higher strength and volumetric behavior changes from contraction to dilation. Similar results have been obtained by [6]. When the fines content is larger than the TFC (50%), an opposite trend is seen because, with lower Cu, soil strength decreases and contractive behavior becomes more obvious.…”

3D DEM simulations of monotonic interface behaviour between cohesionless sand and rigid wall of different roughness

“…The interface between granular material and structure has been investigated using various testing devices and methods [53], e.g. direct shear apparatus [2,7,8,17,19,40,42,43,46,48,49,64,71,73], torsional ring shear apparatus [21,33,37,69], ring shear device [3,23], simple shear apparatus [57,58], plane strain apparatus [49], Couette apparatus [1,33], wear tester [16], three-dimensional simple shear apparatus [11], ring simple shear apparatus [31] and in experiments with piles [61], anchors [65] and silos [49]. The experimental results showed a pronounced effect of the wall roughness, grain size, grain distribution, pressure level, initial density, specimen size and velocity on the peak wall friction angle and wall shear zone thickness.…”

Interfacial studies on different pile materials and their roughness characterisation using 3D optical profilometer

“…For understanding interfacial frictional characteristics between pile and soil, it is crucial to quantify the roughness behaviour of pile materials in fine-grained soils through Absolute roughness R a , Total height R t and Normalised roughness R n [5,6,17,23,32,33]. Figure 6 shows the graphical representation of the two-dimensional roughness parameter for a Travel length L and step size Δx.…”