Grain Size Distribution Of Sand Research Articles

Experimental Analysis of the Changes in Coral Sand Beach Profiles under Regular Wave Conditions

This study utilized 50 laboratory experiments to document the evolution of coral beaches under varying regular wave conditions, including five distinct wave periods and ten wave heights. Both the type of equilibrium beach and the shape of sand bars were used to represent beach evolution. The evolution of coral sand beaches was then compared to quartz sand beaches. The experimental results show that the predicted (modeled) equilibrium profile of a quartz sand beach was not applicable to coral sand beaches. Compared to sand bars on quartz sand beaches, the distance from bar crests to the beach berm in coral sand beaches was greater, whereas the erosional depth of sand troughs was deeper. However, the grain size distribution of sand associated with the coral sand beach under wave action was consistent with Celikoglu’s law. Both an equilibrium beach profile classification model and a sand bar shape prediction model for coral sand beaches were developed based on the experimental data.

Smartphone Digital Image Processing Method for Sand Particle Size Analysis

The grain size distribution of sand provides crucial information for understanding coastal erosion and sediment deposition. The commonly used sieve analysis for grain size distribution analysis has limitations such as time-consuming processes and the inability to obtain information about individual particle shapes and colors. In this study, we propose a grain size distribution analysis method using smartphone digital images, which is simpler and more efficient than the sieve analysis method. During the image analysis process, we effectively detect particles from relatively low-resolution smartphone digital images by extracting particle boundaries through image gradient calculation. Using samples collected from four beaches in Gyeongsangbuk-do, we compare and validate the proposed boundary extraction image analysis method with the analysis method that does not extract boundaries, against sieve analysis results. The proposed method shows an average error rate of 8.21% at <i>D</i><sub>50</sub>, exhibiting a 65% lower error compared to the method without boundary extraction. Therefore, grain size distribution analysis using smartphone digital images is convenient, efficient, and demonstrated accuracy comparable to sieve analysis.

Assessment of a new pluviation system designed to prepare uniform samples of sand

In soil and soil-structure interaction laboratory experiments, the technique applied to prepare the sand deposit remarkably influence the performance of the system, including the stress–strain behavior. Air pluviation techniques represent the most suitable choice when a wide range of densities is required. This study presents the details of a simple and effective air pluviation system designed to be suitable for reconstituting small specimens of sand. Many of the previous studies have focused on traveling the pluviator in the horizontal direction only, without paying much attention to the vertical movement during pluviation. The apparatus described in this paper has the ability to overcome this issue by providing automatic lifting tools to the sand container while the thickness of the sand deposit builds up inside the collecting mold. To understand the influence of grain size distribution of sand on the achieved relative density (RD), three different samples of poorly graded sands were used in the experiments. Parametric studies, including the influence of the height of drop (HD) and deposition intensity (DI) on the relative density, were carried out on the three sand samples. It was observed that the range of obtained RDs depends mainly on the grain size distribution of the sand used. Three distinguished zones were observed in the RD-HD relationship, starting with a linear variation, followed by a nonlinear relationship until achieving a constant RD regardless of the increase of HD value. The uniformity of pluviated sand was assessed using a cone penetration test (CPT). Results of the CPT test showed that denser and more uniform samples could be obtained by raising the container up during the pluviation process.

Experimental Study on the Riverbed Coarsening Process and Changes in the Flow Structure and Resistance in the Gravel Riverbed Downstream of Dams

Following the construction of a reservoir, sediment is intercepted, which greatly reduces the sediment concentration in the discharged flow. This reduction causes riverbed scouring and flow structure adjustments downstream, thereby impacting the river habitat. This study used the generalized flume test with different bed sand compositions and discharge rates to simulate the scouring adjustment process of a sand pebble riverbed channel downstream of a reservoir. The results show that the bed sediment composition affects the water surface gradient, scour depth, turbulence intensity, and sand resistance directly after final scouring. Coarse-grained bed sediment demonstrated the greatest final turbulence intensity and sand resistance, while bed sediments with reduced coarseness exhibited a greater scouring degree; the resistance for sand grains of moderate coarseness showed the greatest change. Sand resistance was exponentially and positively correlated with the median grain size and the fractal dimension of bed sediment mass. The mass fractal dimension expression was suitable for the analysis of bed sand grain-size distribution; it contributed to the calculation of grain resistance with fewer hydraulic parameters. The relationship between the mass fractal dimension and the adjusted grain resistance was also established, which can aid the calculation of the resistance changes in sandy gravel-bed river reaches downstream of reservoirs, enabling the prediction of their effects on aquatic habitats.

Depositional setup and characteristics of the storm deposit by the 2007 Cyclone Sidr on Kuakata Coast, Bangladesh

This study examines the sedimentary characteristics, provenance, and depositional processes of the storm deposits from 2007 Cyclone Sidr that have been identified on the southern coast of Bangladesh. Three sedimentary units up to 70 cm thick have been identified in fifteen geological core collected at a distance of 135–277 m from the coast. Laboratory analyses of grain size, TOC, TN, δ13C, and diatom assemblages were carried out to characterize the deposits. Massive to parallel laminated bluish gray mud underlies the storm overwash deposits. White to light gray, massive to parallel laminated, normal graded 1–17 cm thick sand overlies the mud unit with sharp to erosional contact. The mean grain size and thickness of this sand unit decrease landward with increasing sorting value, where grain size distribution of sand is comparable with modern beach sand. The unimodal sand that dominated the base of the storm deposits grades into bimodal olive-gray sandy silt in the upper part of the deposits. The grain size implies that the sand carried from the beaches and mud likely sourced from the suspended, nearshore sediment of the bay and adjacent rivers. TOC/TN, δ13C values and the presence of brackish mudflat origin diatoms with silty sand laminae in bluish gray mud indicate a tide-influenced environment. Post-storm sand and sandy silt sediments unit contain freshwater and marine-brackish diatoms that have likely been deposited from flooding caused by storm surge water from the bay and overbank flooded river water due to subsequent heavy rainfall. These sediments were sorted according to storm waves and settled over the study area. This study indicates that the low-lying delta coast gets the influences of high water levels both from the bay and the river during a storm. The modern storm deposit will help to characterize the paleo/prehistoric tropical cyclone in geological time for future studies in this area.

Particle breakage of sand subjected to friction and collision in drum tests

This paper presents a laboratory experimental study on particle breakage of sand subjected to friction and collision, by a number of drum tests on granular materials (silica sand No. 3 and ceramic balls) to investigate the characteristics of particle breakage and its effect on the characteristics of grain size distribution of sand. Particle breakage increased in up convexity with increasing duration of drum tests, but increased linearly with increasing number of balls. Particle breakage showed an increase, followed by a decrease while increasing the amount of sand. There may be existence of a characteristic amount of sand causing a maximum particle breakage. Friction tests caused much less particle breakage than collision tests did. Friction and collision resulted in different mechanisms of particle breakage, mainly by abrasion for friction and by splitting for collision. The fines content increased with increasing relative breakage. Particle breakage in the friction tests (abrasion) resulted in a sharper increase but with a smaller total amount of fines content in comparison with that in the collision tests (splitting). For the collision tests, the fines content showed a decrease followed by an increase as the amount of sand increased, whereas it increased in up convexity with increasing number of balls. The characteristic grain sizes D 10 and D 30 decreased in down convexity with increasing relative breakage, which could be described by a natural exponential function. However, the characteristic grain sizes D 50 and D 60 decreased linearly while increasing the relative breakage. In addition, the coefficients of uniformity and curvature of sand showed an increase followed by a decrease while increasing the relative breakage.

Effect of particle size distribution of cohesionless soils on the ultimate carrying capacity of open ended pipe piles under different saturation conditions

This research is performed to study the effect of grain size distribution of cohesionless soils (i.e., fine, medium, and coarse sand) on the ultimate carrying capacity of open-ended pipe pile models of different diameters under different saturation conditions (i.e., fully and partially saturated). Poorly graded clean sand of rounded particles was used as natural soil in the present study. The soil is sieved on standard sieves to obtain fine-, medium-, and coarse-graded soil according to (ASTM D 422-02). Experimental model tests were performed on four open-ended steel pipe piles models with diameters of (25, 30, 35, and 40 mm) embedded within different grain size distribution of sand prepared under fully and partially saturated conditions with specified relative density of 65%. The unsaturated states was achieved by lowering of water table according to matric suction values of soil. The relationship between matric suction and depth of ground water table was measured in suction profile set by using three Tensiometers. The soil water characteristic curve (SWCC) was estimated by applying fitting methods through the program (SoilVision). The results show that the ultimate load carrying capacity of pipe pile under unsaturated conditions is higher than those of saturated condition and increases with increasing of matric suction values. On the other hand, the fine sand shows an increase in ultimate load carrying capacity more than the other grain size distributions under unsaturated conditions for all different types of pipe pile diameters. However, the coarse sand gives a lower resistance at different saturation conditions.

Composite materials with primary lead slag content: Application in gamma radiation shielding and waste encapsulation fields

This paper presents a study on the valorization of primary lead slag as substituent of aggregate in concrete for gamma radiation shielding and as a component of cementitious binders with application in low level radioactive solid waste encapsulation. The first part of the paper outlines the impact of primary lead slag on the compressive strength and gamma radiation shielding properties of concrete. The presence of the primary lead slag as aggregate substituent in concrete, along with steel shot and barite, enhances the density and shielding efficiency against gamma radiation for Ir192, Cs137, Co60 radioactive elements with average gamma energies of 0.37 MeV, 0.662 MeV and 1.25 MeV. The results showed that even the presence of primary lead slag led to a decrease in compressive strength and all the tested concretes exhibited compressive strengths higher than 50 MPa. The utilization of primary lead slag could be recommended as aggregate in heavyweight concrete. The second part of the paper focuses on the experimental investigation of the physic-mechanical properties and low level radioactive solid waste encapsulation capacity of grout based on binders with primary lead slag content. Two binders (30% and 50% lead slag content) were used in cementitious grouts with different binder:sand ratio (1:1, 1:1.5 and 1:2), two types of sand (river sand or crushed concrete sand), different grain size distribution of sand and water/binder ratio of 0.3. It was observed that the grouts exhibit compressive strengths higher than 30 MPa, regardless of the binder:sand ratio. The increase in the binder:sand ratio influenced negatively the flow ability and positively the drying shrinkage. The low level radioactive solid waste encapsulation capacity of studied grout was lower than that of the reference grout with CRT glass waste.

Influence of grain size distribution on dynamic shear modulus of sands

AbstractThe paper presents the results of laboratory tests, that verify the correlation between the grain-size characteristics of non-cohesive soils and the value of the dynamic shear modulus. The problem is a continuation of the research performed at the Institute of Soil Mechanics and Rock Mechanics in Karlsruhe, by T. Wichtmann and T. Triantafyllidis, who derived the extension of the applicability of the Hardin’s equation describing the explicite dependence between the grain size distribution of sands and the values of dynamic shear modulus. For this purpose, piezo-ceramic bender elements generating elastic waves were used to investigate the mechanical properties of the specimens with artificially generated particle distribution. The obtained results confirmed the hypothesis that grain size distribution of non-cohesive soils has a significant influence on the dynamic shear modulus, but at the same time they have shown that obtaining unambiguous results from bender element tests is a difficult task in practical applications.

Effect of Particle Size Distribution of Cohesionless Soil and Pile Diameter on the Behavior of Open Ended Pipe Piles

Pipe piles are normally used in deep foundations to transfer the structure load to stronger layer beneath the ground or to rock formations. More popular applications of pipe piles are marine construction (offshore structures), bridge piers construction and building construction. This research is conducted to study the effect of grain size distribution of cohesionless soil (i.e. fine, medium and coarse sand) on the ultimate load capacity of pipe piles with different diameters under dry and fully saturated state through an experimental model. Also, Degree of soil plugging behaviors for different pipe pile diameters and saturation conditions (i.e. dry, fully saturated conditions) for different particle size distribution was studied. Karbala sand, were used as a natural soil in the present study, it is poorly graded clean sand of rounded particles. The sandy soil is sieved to obtain a fine, medium and coarse graded according to (ASTM D 422-02). The experimental model tests conducted on four open-ended steel pipe piles models with diameters of (25, 30, 35 and 41mm) embedded within different grain size distribution of sand prepared under dry and fully saturated conditions with relative density of 65%. The results shows that, the ultimate load capacity of open-ended pipe piles embedded within medium grain size exerted higher bearing capacity than the other grain size distribution and increased with increasing piles diameters. The increasing values of the ultimate load carrying capacity for different pipe pile diameters under dry conditions are almost greater than that of saturated conditions by about (1.95-2.4) times for fine sand, (2.36-3.04) times for medium sand and (1.62-1.97) times for coarse sand. Furthermore, Plug Length Ratio PLR (which is the proportion of a soil plug length to the pile penetration depth) was measured for different pile diameters, and it was found that the length of soil column increases gradually with the increasing of a piles diameter

Effect of Different Processing on Properties of Silica Sand

This paper will cover some processing routes along with grading and physical/chemical attributes of silica sand. The silica sand in this experiment was divided into four lots, and each of them was processed by the methods of calcining, scrubbing, mulling or rubbing respectively. The test results show that the sand grains which processed by different processing methods are irregular, the acid demand value of sand is lower than that of the base sand, and the grain size distribution of sand is similar to that of the base sand. However, the SiO2 content of processed sand is increased, the impurities content has a downward trend. Compared with the base sand, it can be found that the tensile strength value of molding sand prepared using the processed sands is higher and the bench life is almost no change.

X-ray computed-tomography observations of water flow through anisotropic methane hydrate-bearing sand

We used X-ray computed tomography (CT) to image and quantify the effect of a heterogeneous sand grain-size distribution on the formation and dissociation of methane hydrate, as well as the effect on water flow through the heterogeneous hydrate-bearing sand. A 28 cm long sand column was packed with several segments having vertical and horizontal layers with sands of different grain-size distributions. During the hydrate formation, water redistribution occurred. Observations of water flow through the hydrate-bearing sands showed that water was imbibed more readily into the fine sand, and that higher hydrate saturation increased water imbibition in the coarse sand due to increased capillary strength. Hydrate dissociation induced by depressurization resulted in different flow patterns with the different grain sizes and hydrate saturations, but the relationships between dissociation rates and the grain sizes could not be identified using the CT images. The formation, presence, and dissociation of hydrate in the pore space dramatically impact water saturation and flow in the system.

Online Measurement of the Grain Size Distribution of Sand 0–4 mm used for the production of concrete

AbstractAn apparatus is described for the fast and automatic measurement of the grain size distribution of sand ranging from 0 to 4 mm. A sample of sand continuously introduced at a rate of 30 g/min is separated by the apparatus into seven fractions of 0–0.063, 0.063–0.125, 0.125–0.25, 0.25–0.5, 0.5–1, 1–2, and 2–4 mm. The amount of sand in each of these fractions is determined and the results are given in time intervals of 1 minute. The sand is separated in a separation chamber through which water streams in a horizontal laminar flow. The samples are separated according to their settling velocities. The four coarse fractions descend to the bottom of the chamber. They are collected and weighed under water. The three fine fractions remain suspended in three effluent water streams. The quantity of sand is measured in flow cells by absorption of laser light. Control of the system as well as the collection and processing of the measured data are done by means of an electronic control unit and a microcomputer.

Variability of Sedimentary Textures and Processes on Continental Margin North of Wilmington Canyon: ABSTRACT

Sedimentary properties and processes of a 7,500-km2 corridor seaward of the Baltimore Canyon Trough off New Jersey were studied in detail using over 100 bottom samples consisting of grab samples and box, hydroplastic, and piston cores. The sediments in both canyon and intercanyon areas are primarily bioturbated, olive-gray, sandy silts with local features indicative of gravity-induced mass sediment movements (i.e., graded sequences and load structures). C14-based sediment accumulation rates vary by a factor of three in cores separated by as little as 6 km. These variations seem to be a function of shelf-edge spillover rates. Detailed analyses of the sand grain-size distribution throughout the corridor reveal that the sand component of the slope and rise sediments contains a high percentage of material currently present on the adjacent shelf. The relatively large percentage of sandy sediment in the upper parts of cores from Spencer Canyon suggests its recent role in transporting shelf sediments seaward. Sandy intervals in other slope cores are commonly obscured by intense bioturbation. Cores from the continental rise show an upward decrease in the number of sand layers and lenses. Active transport of sediment to the slope and rise occurred during the late Pleistocene and, although the intensity has declined, the slope is presently the site of deposition for both fine and coarse sediment. End_of_Article - Last_Page 1662------------

Effect of grain-size distribution of sand on the properties of fine-graded concrete

The effect was investigated of the grain-size distribution of 3 sand types on the cement consumption in fine-graded concrete, on its strength properties, frost resistance, and water absorption. The study indicates that a 5 to 10-12% content of sand grains less then 0.14 mm in diameter should be taken as the optimum quantity. Details are given of the tests in which sand was dispersed in fractions which were than blended in the desired proportions. They were then compacted into a cube measuring 10 x 10 x 10 cm on a vibration table to determine porosity in the compacted state. The lowest porosity in the vibro-compacted state was observed in the medium sand, while coarse and fine sand exhibited nearly identical porosity. The compositions of the concrete mixes were calculated, and the compression strengths were determined at 3, 28, and 180 days. Analysis indicated that concrete comprising all 3 sand types and aged 180 days has nearly identical compression and tensile strength, but a difference was observed in the flow rate. The results are also given of 200 alternate freezing and thawing cycles, analysis of change in workability factor, investigations of the physico-mechanical properties, and watertightness factor.

Grain Size Distributions and Depositional Processes

ABSTRACT Extensive textural study of both modern and ancient sands has provided the basis for a genetic interpretation of sand texture. Analysis is based on recognizing sub-populations within individual log-normal grain size distributions. Each log-normal sub-population may be related to a different mode of sediment transport and deposition, thus providing a measure of their importance in the genesis of a sand unit. The three modes of transport reflected are: (1) suspension; (2) saltation; and (3) surface creep or rolling. Each of these is developed as a separate sub-population within a grain size distribution. The number, amount, size-range, mixing, and sorting of these populations vary systematically in relation to provenance, sedimentary process, and sedimentary dynamics. The analysis of th se parameters is the basis for determining the process-response characteristics of individual sand units. A number of processes are uniquely reflected in log-probability curves of grain size distributions of sands and sandstones. These include: (1) current; (2) swash and backwash; (3) wave; (4) tidal channel; (5) fallout from suspension; (6) turbidity current; and (7) aeolian dune. The combination of two or more of these processes also produce characteristic log-probability curve shapes. Ancient sands show some differences from their modern analogues, but these are usually minor. Log-probability plots of ancient sands are directly comparable to those from modern sands. The principal limitation of this study is in comparing sands formed under comparable conditions and obtaining an independent determination of the processes of formation of ancient sands.