Scale dependence of direct shear tests

Zhou, Qiang; Shen, Hayley H.; Helenbrook, Brian T.; Zhang, Hongwu

doi:10.1007/s11434-009-0516-5

Cited by 28 publications

(9 citation statements)

References 19 publications

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“…He believed that the scale effect does not depend only on the grain size of the test material. Examining variability, shape, rotation, slip grains, the average volume of the sample, the distribution of shear stress and development of shear zones, the author showed that the largest factor influencing the bulk friction is the rotation of grains during the test [18].…”

Section: Literature Reviewmentioning

confidence: 99%

Scale Effect in Direct Shear Tests on Recycled Concrete Aggregate

Soból

Sas

Szymański

2015

Studia Geotechnica Et Mechanica

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Abstract:The depletion of natural resources is forcing researchers to explore the possibilities of new aggregates, such as recycled concrete aggregate (RCA). In this article, the mechanical properties and the influence of the size of the direct shear box on the obtained parameters were examined. The study was conducted in two apparatus: medium (120 × 120 mm) and large (250 × 250 mm). In each of these devices, a total of 6 tests were performed: 3 for dry sample and 3 at optimum moisture content. From the results, the conclusions described below have been drawn.

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Section: Literature Reviewmentioning

confidence: 99%

Scale Effect in Direct Shear Tests on Recycled Concrete Aggregate

Soból

Sas

Szymański

2015

Studia Geotechnica Et Mechanica

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“…The choice of DEM parameters is of great importance in reproducing the mechanical properties of granular materials, especially when the results of simulation tests are compared with those of actual laboratory tests quantitatively. Nevertheless, a large amount of DEM simulations reported in the literatures were conducted using empirically evaluated constants [15][16][17][18][24][25][26][27]31]. Since the objective of the present study was to qualitatively investigate the effects of wetting on the responses of granular materials, the parameters were also tentatively chosen on an empirical basis.…”

Section: The Techniques For Dem Simulationsmentioning

confidence: 99%

“…The rapid development of computational capacity and numerical techniques such as the discrete element method (DEM) [13][14][15][16][17][18][19] have provided an effective approach for investigation of microscopic responses of granular materials during wetting. As a conventional topic in unsaturated soil mechanics, the suction effect during wetting has been investigated by many authors using DEM [20][21][22][23][24], and the results obtained have shown that DEM is a rather powerful tool in reproducing the behavior of unsaturated soils.…”

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confidence: 99%

Discrete element simulations of two wetting effects on granular materials

Liu

2011

Chin. Sci. Bull.

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To explore the microscopic responses of granular materials to wetting, the inter-particle lubrication effect and particle breakage in an odometer were simulated using a two-dimensional discrete element method. The lubrication effect was modeled by reduction of the inter-particle friction coefficient and particle breakage was initiated by decreasing the particle strength. Once the strength of the particles decreased to a threshold value, the particles began to break so that new contacts could be established to transfer the external loads. Numerical simulations successfully reproduced the additional compaction of the material and the intensification of the horizontal stress in addition to the microscopic responses of the granular assemblies. The microscopic interpretation of the earth pressure coefficient at rest and the evolution of the grain number distribution during particle breaking were also investigated. granular materials, discrete element method, wetting, lubrication effect, particle breakage Granular materials are extensively used in civil engineering applications such as the foundations of railways and the shells of rockfill dams. These materials are exposed to changes in climate and the environment, which inevitably leads to changes in their long-term mechanical behavior [1]. One typical environmental factor that deserves special attention when designing a granular structure is the interaction between the particles and water from both underground and surface runoff. Water infiltration into the inter-particle pores and the micro-cracks in particles has at least three effects, i.e. the lubrication effect, loss of matric suction and particle breakage [2,3]. These factors often occur in combination and lead to the so-called wetting-induced collapse [3][4][5]. Alonso et al.[3] distinguished the predominant factors according to the sizes of the particles and pointed out that the wetting-induced collapse is primarily caused by particle breakage for coarse granular materials such as rockfill and gravel, while the loss of matric suction is responsible for the collapse of fine materials with grain sizes ranging from 10 to 0.1 mm, such as sands. Both particle breakage and the loss of suction overwhelm the effect of inter-particle lubrication.The wetting-induced collapse may result in unfavorable deformation and stress deterioration in structures; therefore, this phenomenon has attracted a great deal of attention over the past three decades. Many experimental studies [6][7][8][9] have been conducted and great efforts have been devoted to constitutive modeling of this particular behavior of granular materials with the goal of understanding and explaining phenomena observed in the engineering field and numerically solving the boundary value problems in practice [10][11][12]. Among these experimental and theoretical investigations, a phenomenological approach has generally been employed and the macroscopic responses of materials were described within the framework of continuum mechanics [5,[10][11][12]. Nevertheless,...

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“…e shear resistance of gravelly soils basically originates from sliding of particles and particle rolling, so the formation of the shear band closely depends on specimen size and shear gap dimension which represents the opening between shear box halves. And it is reported that the formation of the shear band is the important cause of the scale effect [19].…”

Section: Introductionmentioning

confidence: 99%

A Systematic Method to Evaluate the Shear Properties of Soil-Rock Mixture considering the Rock Size Effect

Ren

Guo-fan

Qiu

et al. 2018

Advances in Civil Engineering

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The soil-rock mixture (S-RM) is widely applied in the geotechnical engineering due to its better mechanical properties. The shear strength, an essential aspect of S-RM which governs the stability and the deformation, is rather necessary to be revealed properly. The extraordinary issue of S-RM compared to fine-grained soils is the grain size effect on the strength analysis. This paper proposes a systematic method to obtain the realistic shear strength of S-RM by detecting the rock size effect. Firstly, based on fractal theory, the rock size was determined as 5 mm by the multifractal property of granular size distribution. Then, based on 2 selected specimen sizes combining the engineering dimension, shear gaps (T) effect and specimen size effect on the shear strength of S-RM have been investigated. It is shown that the gap of the direct shear test decides the physical mechanism of particles forming the shear resistance of S-RM based on the variation of apparent cohesion and mobilized internal friction angle. Specimen size effect is weakened by the gap effect considering the boundary effect. Realistic and stable shear strength parameters of S-RM have been researched by a reasonable gap (0.2–0.4D, where D is the largest particle size).

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Scale dependence of direct shear tests

Cited by 28 publications

References 19 publications

Scale Effect in Direct Shear Tests on Recycled Concrete Aggregate

Scale Effect in Direct Shear Tests on Recycled Concrete Aggregate

Discrete element simulations of two wetting effects on granular materials

A Systematic Method to Evaluate the Shear Properties of Soil-Rock Mixture considering the Rock Size Effect

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