Coarse Granular Materials Research Articles

Geotextile Application for a branch line upgrading

Much of the Midwest North American continent consists of fertile clay terrain with little or no outcropping of rock or coarse granular material suitable for aggregate subballast or ballast material. It is not uncommon to experience considerable subgrade pumping due to subballast segregation or failure to use a subballast, and subgrade failures due to insufficient granular depths, on many branch lines in this area. This paper summarizes the engineering and construction of one of these branch line upgrading in the Midwest United States where locally available non-plastic rock tailings plus geotextile were employed over a transported well-graded granular subballast to prevent fouling by a plastic clay subgrade.

サイロの閉そく限界寸法に関する実験的研究 Ｉ 粗粒材料の流動特性

There are many storage systems for coarse granular materials, such as coal and limestone, These systems include open piles, silos, domes, and storehouses. The silo system is better than other existing systems from the view point of environmental protection, effective use of a site, centralized control, and maintaining the quality of storage materials. For the silo system, however, the most important problem in design is to decide the hopper geometry parameters of the outlet provided at the bottom part of the silo. Blockage and arching in a silo never take place when the hopper geometry parameters are designed appropriately. For use in the theoretical analysis of the hopper section, there are a number of test methods for grasping the properties of fine granulars, but a test method suitable for coarse granulars, such as coal and limestone have yet to be established. This report shows the results of the flow characteristics by means of static compaction and the uniaxial compression test methods. Therefore, the flow characteristics of coarse granular materials, and those at the time of long-term storage are studied here.

Initiation of motion conditions for shale sediments

Critical shear stresses for erosion of alluvial shale particles were investigated in a laboratory flume. Tests in the incipient motion conditions of individual particles showed that entrainment of shale bed particles takes place at mean shear stress values 40–50% smaller than other types of non-cohesive and coarse granular material. The low density and platy shape of the shale particles may induce high lift forces, which would account for a decrease in the resistance to erosion of shale channels and greater rates of bed-load transport. Keywords: channel stability, critical shear stress, flume tests, initiation of motion, shale gravels, single particles, weak bed material movement.

The rate of discharge of coarse granular material from a wedge-shaped mass flow hopper

The equations of continuity and momentum balance for a cohesionless Coulomb powder discharging from a wedge-shaped hopper are solved by an iterative procedure, which generates series solutions in inverse cubic powers of distance from the vertex of the hopper. Computed residues indicate that the results are more accurate than existing approximations in the literature. Nevertheless, the gap between theory and experiment is not closed. This points to an inadequacy in the theoretical model.

Renal pathology of fetuses with congenital nephrotic syndrome of the Finnish type. 2. A qualitative and quantitative electron microscopic study.

A qualitative and quantitative transmission electron microscopic study was performed on kidneys of fetuses with congenital nephrotic syndrome of the Finnish type (CNF) and controls obtained from elective pregnancy terminations. The gestational age of the fetuses ranged from 16–22 weeks. A consistent qualitative change of CNF glomeruli was the nearly total loss of epithelial cell foot processes, with smudging of epithelial cytoplasm as broad masses on the glomerular basement membrane. Adjacent to the basement membrane there were increased amounts of fibrillar material in the epithelial cytoplasm. The number of pinocytic droplets was increased both in epithelial and endothelial cytoplasm and some of the capillary loops showed swelling of endothelial cells with poor fenestrations in cases of CNF. Mesangial hyperplasia was focally evident in the most mature CNF glomeruli with an increase of the mesangial matrix. A striking qualitative feature in CNF, only rarely seen in controls, was the occurrence of electron lucent vacuoles and heteromorphic residual bodies in the mesangial cell cytoplasm. The total thickness of the glomerular basement membrane was comparable in CNF and controls but the width of the lamina densa was significantly smaller in CNF than controls. Lamina rara interna of the basement membrane showed irregular widening with accumulation of coarse granular material. Reabsorption droplets of proximal tubular cytoplasm were significantly increased in CNF. With the dilatation of the tubule the droplets almost totally disappeared. Based on the results of the study it is suggested that the basic pathogenetic defect in CNF lies in faulty development of the lamina densa of the glomerular basement membrane and, secondary to this, various glomerular and tubular changes occur. In addition to evidence of extensive foot process fusion, mesangial cell cytoplasmic vacuoles represent a diagnostically important qualitative change in the glomeruli of fetal CNF.

The thickness of the shear zone of flowing granular materials

Measurements have been made of the velocity profiles in the flow of coarse granular materials from parallel sided bins. It has been established that in the upper part of the bin the material is in plug flow except for narrow shear zones adjacent to the walls. The width of these zones was found to be of the order of 5 times the particle diameter and was essentially independent of height, flow rate and wall roughness. The observed velocity profiles could not be explained by conventional theories and a purely geometric explanation is proposed.

Viruslike particles associated with lesions in larval pacific oysters ( Crassostrea gigas)

A recent report (Leibovitz et al., 1979) described a serious disease of hatchery-reared larval Pacific oysters, Crassostrea gigas. Subsequent electron microscope analysis of the diseased oyster larvae demonstrated hexagonal viruslike particles associated with the previously reported prominent velar lesions. The particles were found only in the velar epithelium and measured 228 ± 7 nm SD in diameter. Serial sections showed that particle-containing cells were vacuolated, poorly defined, and contained intracytoplasmic inclusions observable at the light microscope level. Electron microscopy showed both complete and incomplete particles. Complete particles were usually associated with electron-lucent vacuoles while incomplete particles were associated with masses of coarse granular material. The indications of viral replication and association of particles with lesions prompt further studies to define the role of a viral agent in the etiology of this disease.

Cytology of the Superficial Keratinised Cells in Experimental Keratitis Sicca

Keratoconjunctivitis sicca was produced in 2 rabbits by the surgical extirpation of the tear-secreting glands and the nictitating membrane in one eye. Flat mounts of the superficial corneal epithelium were prepared by the in vivo replica technique. Histomorphological and cytological studies of the keratinised cells showed the irregularly arranged, crumpled and piled-up cells. The cells contained coarse granular and fibrillar material in the cytoplasm and large granules in the nuclei. The reaction for -S-S- bridges was positive in these cells. They showed birefringence under polarisation microscopy but possessed some ribonucleoproteins.

The rate of discharge of coarse granular materials from conical mass flow hoppers

The problem of predicting the rate of discharge of a granular material from a conical mass flow hopper has been examined. From the momentum equations upper and lower limits for the discharge rates have been obtained and are presented in the form of graphs. The difference between these limits is sufficiently small that their mean gives an estimate of the discharge rate which is accurate enough for design purposes. Measurements of discharge rates using three hoppers and four materials show that the theory predicts the discharge rate within 8% for coarse material, but that for particles less than about 500 μm the measured flow rate is less that that predicted; this is believed to be due to the fact that for such particles the effect of differences of air pressure are not negligible, as has been assumedinthe theory.

The ability of debris, heavily freighted with coarse clastic materials, to flow on gentle slopes

ABSTRACTObservations of many debris‐flow deposits on gently‐sloping alluvial fans have disclosed that debris commonly is heavily loaded with coarse clastic material and contains large isolated blocks. The paper describes how debris charged with coarse granular material can transport large blocks, yet flow on gentle slopes.Experimental results of mixing sand‐sized particles with a slurry of clay plus water indicate that 45–55 vol. % of a single size, and up to 64% of two selected sizes, can be added before interlocking occurs. Theoretical analysis of multi‐size classes suggest that 89 to more than 95 vol. % debris can be clastic materials without significant particle interlocking.The clay fraction, even if minor, plays a critical role in determining strength properties of debris. The mixture of clay plus water provides a cohesive slurry that supports fine‐grained particles within the debris, as well as reduces the effective normal stresses between the particles. The increased unit weight of the clay plus water plus fine‐grained particles allows the support of coarser grained particles. The pyramiding upon the clay‐water slurry continues until the entire debris mass is supported in a virtually frictionless position because of the reduced effective normal stress and the lack of particle interlocking.Thus, the ability of debris flows to support large blocks can be understood in terms of the high unit weight of the displaced debris plus the strength of the fluid phase; that is, the blocks float in the debris as a result of a small density difference between the blocks and the debris, plus the cohesive strength of the clay‐water slurry.Also, the ability of coarse clastic debris to flow on gentle slopes probably is a result of poor sorting of debris‐flow materials which contain minor amounts of clay. The poor sorting allows the debris to have a high density yet have essentially no interlocking of clasts. The high density of the debris reduces effective normal stresses between clasts, thereby reducing apparent friction of the mixture.

Aerial Photographic Interpretation of Soft Ground (Part 1)

(II) A trial of interpretation of soft ground by the morphometric analysis of micro-geomorphology.1) A study based on the methods and techniques of “micro-landform” analysis on aerial photographs mentioned previously is carried out in case of the alluvial lowlands in the lower Tenryu River Region, close to Hamamatsu City, on the Pacific coast of Central Japan, before the discussin on the morphometric analysis of micro-geomorphology. From this study, the methods of the systematic classification of “micro-landform units” are proved to be useful to infer but surface materials also the surface layer type of soft ground.2) However the surface distribution ranges and types of soft ground are ascertained, the depth or thickness of the soft ground is not determined. As mentioned by Belcher (1960), it is difficult to interpret the thickness or depth of materials from aerial photographs. In order to examine the possibility of interpretation of the thickness of soft muddy layers which compose soft ground from aerial photographs, it is necessary to study the relationship between the thickness of the layers and the micro-geomorphological features seen on the photographs. For this purpose the writer tried to measure the distribution pattern of the “micro-landform units” by a simple morphometric analysis using aerial photographs. The morphometric data are compared with the geologic data obtained from bore hole excavations, in case of the alluvial lowlands formed by the Tenryu and the Ota Rivers.The distribution pattern of the “micro-landform units” is measured by “Micro-Relief Ratio (MR) ” defined byMR=Total area of micro-relief in a unit area/Unit area (1 sq. km.) ×100 (%) .Where, micro-relief means areas of shight elevation such as former channel bars, natural levees, etc., as well as abandoned low water channels.The value of MR shows the distribution density of coarse granular materials on the surface of alluvial lowlands, and the relative area formed by muddy deposits. From Fig 2-2., the total value of MR in a lowland area is thought to be a approximate index showing the geomorphic development processes, the stability of the depositional environment and the ratio of the volume of fine grained materials to the total volume of materials transported by the rivers in the recent years. Consequently, one can expect that the smaller velues of MR indicate thicker fine grained deposits.Based on these hypotheses, the relationship between MR and the thickness of muddy deposits including peat layers (UM & LM) is analyzed and discussed. Furthermore, the relationship between the “Damage Percentage (DP) ” of wooden houses caused by To-Nankai Earthquake in 1944 and MR is discussed.3) The correlation between the thickness of muddy deposits (Tm) and the value of MR is not so distinct as shown in Fig. 2-11 a & b. But, generally speaking, Tm increases exponentially with decreasing MR. The maximum thickness of UM appears at the value of MR between 8% and 32%, and the total thickness of UM and LM exceeds more than 30m. or 40m. at the value of MR of less than 20%. When the mean value of MR was calculated in the 1km. zone crossing the lowlands (MR mean), it is the area where MRmean is less than 20% or 30% that one can expect the coexistence of both surface layer type (UM) and deep layer type (LM) of soft ground. And in such areas, for instance natural levee zone and lagoonal delta of the Ota River, one can also expect that the total thickness of soft muddy deposits is greater than 30m. or 40m (see Fig. 2-10) .

Aerial Photographic Interpretation of Soft Ground (Part 1)

(II) A trial of interpretation of soft ground by the morphometric analysis of micro-geomorphology.1) A study based on the methods and techniques of “micro-landform” analysis on aerial photographs mentioned previously is carried out in case of the alluvial lowlands in the lower Tenryu River Region, close to Hamamatsu City, on the Pacific coast of Central Japan, before the discussin on the morphometric analysis of micro-geomorphology. From this study, the methods of the systematic classification of “micro-landform units” are proved to be useful to infer but surface materials also the surface layer type of soft ground.2) However the surface distribution ranges and types of soft ground are ascertained, the depth or thickness of the soft ground is not determined. As mentioned by Belcher (1960), it is difficult to interpret the thickness or depth of materials from aerial photographs. In order to examine the possibility of interpretation of the thickness of soft muddy layers which compose soft ground from aerial photographs, it is necessary to study the relationship between the thickness of the layers and the micro-geomorphological features seen on the photographs. For this purpose the writer tried to measure the distribution pattern of the “micro-landform units” by a simple morphometric analysis using aerial photographs. The morphometric data are compared with the geologic data obtained from bore hole excavations, in case of the alluvial lowlands formed by the Tenryu and the Ota Rivers.The distribution pattern of the “micro-landform units” is measured by “Micro-Relief Ratio (MR) ” defined byMR=Total area of micro-relief in a unit area/Unit area (1 sq. km.) ×100 (%) .Where, micro-relief means areas of shight elevation such as former channel bars, natural levees, etc., as well as abandoned low water channels.The value of MR shows the distribution density of coarse granular materials on the surface of alluvial lowlands, and the relative area formed by muddy deposits. From Fig 2-2., the total value of MR in a lowland area is thought to be a approximate index showing the geomorphic development processes, the stability of the depositional environment and the ratio of the volume of fine grained materials to the total volume of materials transported by the rivers in the recent years. Consequently, one can expect that the smaller velues of MR indicate thicker fine grained deposits.Based on these hypotheses, the relationship between MR and the thickness of muddy deposits including peat layers (UM & LM) is analyzed and discussed. Furthermore, the relationship between the “Damage Percentage (DP) ” of wooden houses caused by To-Nankai Earthquake in 1944 and MR is discussed.3) The correlation between the thickness of muddy deposits (Tm) and the value of MR is not so distinct as shown in Fig. 2-11 a & b. But, generally speaking, Tm increases exponentially with decreasing MR. The maximum thickness of UM appears at the value of MR between 8% and 32%, and the total thickness of UM and LM exceeds more than 30m. or 40m. at the value of MR of less than 20%. When the mean value of MR was calculated in the 1km. zone crossing the lowlands (MR mean), it is the area where MRmean is less than 20% or 30% that one can expect the coexistence of both surface layer type (UM) and deep layer type (LM) of soft ground. And in such areas, for instance natural levee zone and lagoonal delta of the Ota River, one can also expect that the total thickness of soft muddy deposits is greater than 30m. or 40m (see Fig. 2-10) .

A Direct Recording Instrument for Size Analysis of Coarse Granular Material

I HAVE constructed a modified form of Emery's sedimentation tube1, by the help of which a direct picture of the size distribution of particles of coarse granular material can be obtained without recourse to calculations, computations and graphical representations. The new instrument consists mainly of a special form of long settling tube and a constant-speed revolving drum as shown in Fig. 1. The successive cumulative heights of the sedimentation column, over the entire period of analysis, are recorded on a photographic paper wrapped over the cylindrical drum. This photographic record at the successive stages of analysis presents a direct picture of the size-distribution character of the particles of the material analysed.

Some observations on the effect of particle shape on the movement of coarse sediments

During a study in which information was gathered to improve the design of unlined canals in coarse granular materials, an opportunity was afforded to study the effect of particle shape on the movement of coarse sediments. This paper summarizes the various measurements and analyses that were made on samples of bed material from several canal sections in the San Luis Valley in Southern Colorado. Some comparisons are made to show the resistance to movement of various shaped particles according to sphericity and Zingg type. It is pointed out that flat particles tend to become imbricated, and they resist movement more than spherical particles of equal weight. Some observations are made on the effect of dilatancy on scour and sediment movement.

Post-Glacial Drainage Changes in the Darnley Bay Area, N. W. T., Canada

POST-GLACIAL DRAINAGE CHANGES IN THE DARNLEY BAY AREA, N. W. T. , CANADA* J. Ross Mackay University of British Columbia Darnley Bay is north of Great Bear Lake and midway between the Mackenzie and Coppermine Rivers which flow north into the Arctic Ocean. The three rivers which drain the area, namely the Brock, Hornaday , and Horton Rivers, are inaccurately shown on the latest 8 mile topographic sheet which was published in 1945, but a new and accurate map prepared from aerial photographs will shortly be available. Darnley Bay was discovered by Dr. John Richardson in 1826 but part of the inland area is still largely unknown. The mouth of the Horton River was discovered by Richardson and the river itself explored by Vilhjalmur Stefansson and Rudolph Anderson in 1909-12. ^ A, J. Stone, an American naturalist collecting for the American Museum of Natural History, discovered the Hornaday River in 1898. Until recent years the large size of the Hornaday River was unsuspected and it was considered to be a small stream rising from a lake 10 miles south of Darnley Bay, when in reality the river is about 200 miles long and the lake does not exist. The southern party of the 1913-18 Canadian Arctic Expedition explored the Brock River for 23 miles from its mouth. ^ Air photographs show it to be some 80 miles in length. The purpose of this paper is to discuss some of the post-glacial drainage changes which have occurred in the drainage basins of the Brock, Hornaday and Horton Rivers in the Darnley Bay area. Field work was done in the summer of 1951 and liberal use has been made of photo interpretation in extending the study to include a larger area. General Description The Darnley Bay region is in the barren grounds or tundra beyond the tree limit which lies close to the Horton River. Permanently frozen ground or permafrost is usually within five feet of the surface, except in areas of coarse granular materials. The area straddles the western boundary of the Canadian Shield which is shown on present geologic maps as reaching the coast at the southern end of Darnley Bay just east of the mouth of Brock River. In reality, the boundary should be shifted to the northeast because there is an area of Tertiary (?) sediments which are exposed northeast of Brock River and outcrop in an area of over 100 square miles. 5 The entire region was glaciated, and morainic material blankets most of the bedrock within 30 to 40 miles of Darnley Bay (excluding Parry Peninsula) but large areas of bedrock are exposed at the surface farther inland. Evidences for two directions of ice movement approximately at ?Based on field investigations carried out for the Geographical Branch, Department of Mines and Technical Surveys, Ottowa, with whose permission this paper is published. Thanks are due to Keith Fraser for his assistance in the field. 18 Yearbook of the Association Vol. 15 CAPE PARRY MILES Figure 1. Map of Darnley Bay area showing glacial lineatlon in ground moraine and bedrock with inset map to show general location 1953 of Pacific Coast Geographers 19 ,CAPE PARRY FRANKLIN BAY DARNLEY BAY CHANNEL A IIIBIIIIH.Î*·M >» MILES Figure 2. Map showing the principal post-glacial drainage channels. Dashed boundaries have been used to delimit drainage channels about which there is some uncertainty. 20Yearbook of the AssociationVol. 15 right angles to each other occur in the terrain. A general east-west trend is apparent across Parry Peninsula changing to a northeastsouthwest trend on the east side of Darnley Bay. This movement coincides with that of no known ice center. The other principal direction is found south and southeast of Darnley Bay where the ice moved from south to north, with a westerly component. This direction is a continuation of the projected trend from the Great Bear Lake area. Poet-Glacial Stream Capture As déglaciation progressed, the streams followed in general the regional slope of the land and drainage was in a chaotic state. It is possible to reconstruct much of the early drainage pattern from the evidences given by large, dry, abandoned valleys and also by misfit streams. The former drainage channels...