Effect of grain crushing and bedding plane inclination on Aqaba sand behavior (original) (raw)

Effect of Grain Crushing and Bedding Plane Inclination on Ras en-Naqab Natural Sand Behavior

2009

This pa per p resents an e xperimental investigation f or i nherent ani sotropy an d particle breakage f or n atural Ras en-Naqab sand so uthern J ordan. The nat ural s and s pecimens were subjected to one dim ensional compression to induce breakage. Th e grain size distributions of the s pecimens were re ported before and aft er th e application of the stre sses. The reafter, t he sand s hear st rength parameters were asses sed using direct shear box t ests. E xamining t he obtained results revealed that the amount of breakage due to one dimensional compression is of order higher t han t he amount occ urring d uring di rect shear t est. Peak shear s trength parameters h ave little o r no ch ange w ith in creasing particles b reakage. H owever, d ilatancy component o f shear st rength di minishes w ith i ncreasing the am ount of part icles breakage. Moreover, exa mining t he effect of a ngle of de position shown a cons iderable am ount of dilation occurs on the higher deposition angle regardless the extent of breakage reported.

Particle breakage during shearing of a carbonate sand

Géotechnique, 2004

A series of ring shear tests was conducted to investigate the development of particle breakage with shear strain for a carbonate sand. It was found that at very large displacements the soil reached a stable grading, but that the final grading was dependent on both the applied normal stress and the initial grading. The particle breakage caused a volumetric compression, which again ceased only when the stable grading had been attained, emphasising that critical states as observed at much smaller strains in triaxial tests are not rigorously defined. Despite the severe degradation of the soil particles the mobilised angle of shearing resistance was found not to change significantly.

The role of particle breakage in the mechanics of a non-plastic silty sand

Soils and Foundations, 2013

A detailed investigation was carried out on a silty sand from Boˇstanj, Slovenia, in order to identify the role that particle breakage plays in test interpretations and mechanics. The soil was tested up to a high pressure in the triaxial and oedometer apparatus. Unexpected for a silty sand, the basic patterns of behaviour, in terms of strength and stiffness, were found to be similar to those of many previously investigated clean sands, with unique and parallel Normal Compression and Critical State Lines at higher stress levels and a horizontal asymptote to the Critical State Line at lower stress levels. The stiffness was controlled primarily by the state of the soil relative to the location of these lines. Despite the better grading, there was still very significant particle breakage. However, the breakage was largely confined to the coarse fraction. The grading curves after various tests all showed convergence with the initial grading towards 1 mm, which may therefore represent the comminution limit. It is believed that it is the particle breakage that caused the behaviour to follow a simple Critical State type of framework and why transitional or non-convergent compression behaviour was not found.

Effect of Particle Morphology, Compaction, and Confinement on the High Strain Rate Behavior of Sand

Experimental Mechanics, 2017

The effect of grain shape, size distribution, intergranular friction, confinement, and initial compaction state on the high strain rate compressive mechanical response of sand is quantified using Long Split Hopkinson Pressure Bar (LSHPB) experiments, generating up to 1.1 ms long load pulses. This allowed the dynamic characterisation of different types of sand until full compaction (lowest initial void ratio) at different strain rates. The effect of the grain morphology and size on the dynamic compressive mechanical response of sand is assessed by conducting experiments on three types of sand: Ottawa Sand with quasi-spherical grains, Euroquartz Siligran with subangular grains and Q-Rok with polyhedral grain shape are considered in this study. The adoption of rigid (Ti64) and deformable (Latex) sand containers allowed for quasi-uniaxial strain and quasi-uniaxial stress conditions to be achieved respectively. Additionally, the effect of intergranular friction was studied, for the first time in literature, by employing polymer coated Euroquartz sand. Appropriate procedures for the preparation of samples at different representative initial consolidation states are utilized to achieve realistic range of naturally occurring formations of granular assembly from loose to dense state. The results identify material and confining sample state parameters which have

Roles of Particle Breakage and Drainage in the Isotropic Compression of Sand to High Pressures

Journal of Geotechnical and Geoenvironmental Engineering, 2017

The roles of particle breakage and drainage conditions on the quasi-static compression response of sand were evaluated by comparing the results from drained and undrained isotropic compression tests on dry and saturated specimens up to a mean total stress of 160 MPa. For dry sand specimens, the compression curves from drained and undrained tests were similar due to the high compressibility of air. The isotropic compression curves of the dry sand specimens at mean stresses greater than 30 MPa reflect a transition toward void closure, reaching a minimum void ratio of 0.04 at 160 MPa. Dry sand specimens with different initial relative densities showed similar behavior during isotropic compression in drained conditions for mean stresses greater than approximately 30 MPa. As expected, saturated specimens tested under undrained conditions showed a much stiffer response than in drained conditions, with a bulk modulus greater than that of water. Increasing trends in particle breakage quantified using the breakage factors of Marsal and Hardin with increasing mean stress were observed for the dry sand specimens, but negligible particle breakage was noted for the saturated specimens tested in undrained conditions. To highlight the linkage between particle breakage and the transition to void closure at high mean effective stress, an empirical relationship was developed using Hardin's relative breakage index to match the experimentally-derived compression curves of dry sands under drained conditions.

Effects of particle characteristics on the shear strength of calcareous sand

2017

The paper presents a 3D analysis (3DA) to evaluate the particle shape and size of silica and calcareous sands. The particles of calcareous sand are found to be less spherical than those of silica and crushed calcareous sands. Furthermore, the results indicate that the average sphericity (SPH) holds an inverse relationship to the particle size. However, in each sample the larger particles have higher SPHs than the smaller particles. In addition, the 3DA yields smaller particles than the sieve analysis (SA). Owing to a variety of particle shapes, causing particle interlocking, especially for calcareous sand, the particles cannot pass through the sieves by their shortest dimension. This paper discusses the effects of particle characteristics on the shear strength properties. Although the calcareous sand shows higher peak and residual shear strength properties, it tends to reach a lower shear strength at a small shear strain and a lower dilation than the silica sand. Moreover, the findi...

The Consequence of Particle Crushing in Engineering Properties of Granular Materials

This paper presents experimental investigation for particles breakage for natural sand. The particle breakage was induced by subjecting the sample to one dimensional compression. Grain size analyses were performed before and after induced breakage. Thereafter, the sand shear strength parameters were assessed using direct shear box tests and the coefficient of permeability was assessed using constant head permeameter. Examining the obtained results revealed that the amount of breakage due to one dimensional compression was of order higher than the amount occurring during direct shear test. Peak shear strength parameters decreased with the particles breakage increasing. Moreover, dilation angle of shear strength pronouncedly decreases with the amount of particles breakage increasing. Crushing has obvious effect on the evaluated coefficient of permeability.

Influence of Grain Sizes on Undrained Strength of Sand Mixtures

International Journal of Innovative Technology and Exploring Engineering, 2019

Sand is known as the main material in land reclamation works to develop and widen an area. It is important for the Geotechnical Engineer to ensure the sand used can accommodate the burden imposed from the structures to be built on it. Previous researchers have conducted studies on the strength of sand, whether focusing on the sand itself or with the presence of fines. However, the study of sand grain size effects in sand mixtures in affecting sand behavior is extremely limited. The sizes and angularity of the sand particle are believed to contribute to the behavior of sand mixtures soil. Hence, the study to investigate the effect of sand grain size on sand mixtures in term of undrained strength is being carried out. The sand was sieved to coarse sand, medium sand and fine sand then each size was mixed with kaolin at 0 %, 20 % and 40 %. The undrained strength was obtained from triaxial test on undrained condition. As a result, it is found that the maximum deviator stress, qmax increa...