Optimizing the Compaction Characteristics and Strength Properties of Gravelly Soils in terms of Fine Contents

Abstract

Gravelly soils are widely adopted as civil construction materials in engineering practice. Although the influence mechanism of fine contents (FCs) on the mechanical behavior of gravelly soils has been emphasized in the previous studies, few discuss the compaction and strength properties concurrently. Besides, FCs of gravelly soils were discussed separately in many cases regardless of the variation in water content. In this study, modified Proctor compaction test and medium-sized triaxial test were performed to investigate the mechanical properties of gravelly soils containing different magnitudes of fine contents. It is shown that an optimum FC exists for gravelly soils although the value of the optimum FC varies with grading curves of the coarse-grained portion. By adjusting FC in the gravelly soils, not only could the maximum dry density ρdmax be improved but also the optimum saturation degree Sropt rises significantly, and synchronously, the minimum air void ratio v a min decreases notably. Besides, fine particles are just right to fill with the voids formed by the coarse-grained skeleton for the optimum FC sample. The soil structure corresponding to the optimum FC status can be termed as a densely filled skeleton structure, which is the densest and most stable. As fine contents increase or decrease from the optimum value, soil structure will loosen and deteriorate the mechanical properties. In addition, the increase in water content has quite different effects on strength properties of gravelly soils with different FCs in a triaxial test due to the opposite effects of pore water softening and negative pore pressure strengthening. Such results are expected to provide guidance for the preparation of gravelly soils in engineering practices.

An Inclusive Study on the Effect of Strain Rate on the Stress-Strain Behavior and the Undrained Shear Strength of Clay Soils in Kombolcha, Ethiopia

“…The trials were conducted with increasing strain rate of 0.5% (0.38mm/min), 0.75% 1% (0.76mm/min), 1.25% (0.95mm/min) and 1.5% (1.14mm/min) of specimen height with confining pressure of 50kPa, 100kPa, and 150kPa in order to assess the better strain rate for Kombolcha clay soils. A failure envelope was used to determine the shear strength parameters of the test samples [31][32][33].…”

GIS mapping used as supplementary tool to experimentally investigated subgrade soil for robust pavement design in rural area of Ethiopia

“…Soils are highly inconstant and adaptable in nature that needs to be investigated and explored of their actual behavior before designing followed by construction (Wendel et al , 2020; Zhao et al , 2021). Soil which forms the subgrade for roads and highway projects performs like the foundation of a building to provide stability and durability to the construction (Hopkins et al , 2006; Lollo, 2016; Surendra and Sanjeev, 2017; Jean-Sebastien and Tom, 2020).…”

Experimental Study on the Effect of Compaction Work and Defect on the Strength of Soil‐Rock Mixture Subgrade

“…Soil-rock mixture is a complex discontinuous medium material, which was composed of stones, soils as filling components, and pores. It has the characteristics of complex geological origin, diverse composition, and extremely uneven soil and rock particles across multiple orders of magnitude scales and structures [1][2][3][4]. Because soil-rock mixture is easy to get, it is often used for roadbed filling in construction [5].…”

“…In addition to rock content, the influence of rock particle size, water content, and other parameters on the engineering characteristics of soil-rock mixture is also considerable [4,19,20]. e change of water content will affect the shear strength of soil, thus affecting the bonding strength of soilrock interface.…”