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Monkul, Mehmet Murat, i Jerry A. Yamamuro. "Influence of silt size and content on liquefaction behavior of sands". Canadian Geotechnical Journal 48, nr 6 (czerwiec 2011): 931–42. http://dx.doi.org/10.1139/t11-001.
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This study investigates the fines content influence on liquefaction potential of a single base sand mixed with three different essentially nonplastic silts through strain-controlled monotonic undrained triaxial compression tests. Confining stress (30 kPa) and deposition method (dry funnel deposition) were kept the same, while fines content was varied, to solely focus on how different silts and their contents influence the undrained response of the sand under comparable conditions. It was found that if the mean grain diameter ratio (D50-sand/d50-silt) of the sand grains to silt grains is sufficiently small, the liquefaction potential of the sand increases steadily with increasing fines content for the studied range (0%–20%). As D50-sand/d50-silt increases, the liquefaction potential of the silty sand might actually be less than the liquefaction potential of the clean sand. Test results also revealed that commonly used comparison bases (i.e., void ratio, intergranular void ratio, relative density) are not sufficient for assessing the influence of fines on liquefaction potential of silty sands. Finally, relative size of the silt grains should also be considered in geotechnical engineering practice in addition to content and plasticity of fines to characterize the influence of silt on liquefaction potential of sands.
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Gazi, Md Yousuf, SM Mainul Kabir i Md Badrul Imam. "Silt content approximation of Neogene Surma group mudrocks, Sitakund anticline, Bengal basin". Bangladesh Journal of Scientific Research 30, nr 1-2 (25.03.2018): 35–43. http://dx.doi.org/10.3329/bjsr.v30i1-2.36118.
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Petrography of the Neogene mudrocks in this study incorporates laser particle size analysis, thin sections and scanning electron microscopy (SEM). Ten representative mudrock samples were collected from outcrops of the Sitakund structure. From the studies, it is evident that mudrocks of Sitakund structure are characteristically silty. The silt content, as estimated by laser grain size analysis, of the mudrocks ranges from 39 to 77% with average of 58%. Significant amount of granular silt with the platy clay minerals is also evident from the SEM micrographs. The silts are mainly quartz, feldspar and micas. The high silt content in the Neogene mudrocks implies an enormous flux of silty sediments with a very high rate of sedimentation allowing little time for a more selective sorting. This supports the geologic history that the uplifting and erosion of Himalaya was at the peak during Miocene and the Ganges mega delta received highest rate of sedimentation and growth rendering shale consistently silty.Bangladesh J. Sci. Res. 30(1&2): 35-43, December-2017
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Wang, Ke Dao, i Jin Hua Wang. "Tendency of Beach Surface between Maojiagang Two Moles". Advanced Materials Research 621 (grudzień 2012): 292–95. http://dx.doi.org/10.4028/www.scientific.net/amr.621.292.
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After Maojiagang two moles was established, beach surfaces between two moles have occurred obvious silt up, rush to silt tendency and have occurred obvious change. The speed that beach surface silts up has occurred obvious change: In first year, it is rapid that beach surface silt up; Second year, beach surface silts up obvious slack off , and reaches balance step by step; After 3 years, beach surface silt up was obvious seasonal change elevation change.
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Shu, Shi, Xiaohuan Zhou, Yujie Gong, Haohui Wang, Yan Tang i Junhao Chen. "Strength and Contaminant Toxicity Leaching Characteristics of MgO-Solidified Silt". Processes 12, nr 6 (25.05.2024): 1086. http://dx.doi.org/10.3390/pr12061086.
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Abstract: In this study, MgO as an environmentally friendly silt-solidifying material was first mixed with silt and then carbonized by injection with CO2. The strength and contaminant leaching characteristics of the MgO-solidified silt were studied using unconfined compressive strength and toxicity leaching tests, and the results were compared with those of cement-solidified silt. The unconfined compressive strength of the silt reached 111 kPa with 9% MgO content and a 14 d curing time. The CO2 injection further increased the unconfined compressive strength of the MgO-solidified silt by approximately 25%: the values for MgO-solidified silts without and with a CO2 injection were approximately 60% and 80%, respectively, of those of the cement-solidified silts with the same additive additions. The leaching concentrations of nutrient salts and heavy metal pollutants in the silt decreased with increased MgO content. Compared with the dredged silt, MgO solidification with carbonization reduced the leaching of total nitrogen and total phosphorus by more than 10% and 50%, respectively: these values were approximately 5% points higher than those of cement-solidified silt. Of the heavy metals, the leaching concentration of Ni was reduced the most. This study provides a theoretical basis and technical support for low-carbon treatment and green resource utilization of dredging silt.
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Polito, Carmine P., i James R. Martin. "A Reconciliation of the Effects of Non-Plastic Fines on the Liquefaction Resistance of Sands Reported in the Literature". Earthquake Spectra 19, nr 3 (sierpień 2003): 635–51. http://dx.doi.org/10.1193/1.1597878.
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The literature presents several seemingly contradictory reports concerning the effects of non-plastic (i.e., silty) fines content on the liquefaction resistance of sands. These seemingly contradictory trends were reconciled in light of the results of a recent study by the authors that linked cyclic resistance and relative density. It was shown that the trend of decreasing cyclic resistance with increasing silt content reported in the literature could be explained by considering the soil's relative density. The same argument was made for the trend of decreasing and then increasing cyclic resistance with increasing silt content. The concept that cyclic resistance is controlled by the sand skeleton void ratio of the soil was also reconciled with the results of the authors’ previous study. The trend of increasing cyclic resistance (without a corresponding initial decrease) with increasing silt content that has been reported in the literature does not appear to occur in non-plastic silts.
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Fraser, T. A., i C. R. Burn. "On the nature and origin of "muck" deposits in the Klondike area, Yukon Territory". Canadian Journal of Earth Sciences 34, nr 10 (1.10.1997): 1333–44. http://dx.doi.org/10.1139/e17-106.
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Organic-rich "muck" deposits, which blanket auriferous gravels in the Klondike area, Yukon Territory, comprise two principal stratigraphic units: (i) a silty Late Pleistocene deposit, and (ii) Holocene organics lying unconformably on the silt. The deposits are found predominantly in valley bottoms and, if undisturbed, are normally perennially frozen. Field and laboratory investigations of particle size, mineralogy, and morphology, as well as organic matter and sedimentary structures, indicate that the silt is both primary (massive) and redeposited (bedded) loess (by weight 87% medium and coarse silt and fine sand). Radiocarbon dates indicate that the loess was deposited during Late Wisconsinan McConnell glaciation, beginning after 27 000 14C years BP. The loess was likely derived from the floodplain of the Yukon River during periods of low flow. Turf in growth position and organic matter in the silt similar to that of loessal grasslands near Kluane Lake suggest a grassland environment for the area during McConnell glaciation. A mummified carcass in the silts indicates that some of these sediments have been frozen since shortly after deposition. Ice wedges are commonly found in the upper portion of the silt, but these wedges rarely extend into the overlying organic material. Separate, smaller ice wedges are found in the Holocene unit. Radiocarbon dates indicate that peat growth began at the start of the Holocene, as in other unglaciated portions of Yukon, when the climate became abruptly wetter.
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Rogers, C. Brent, Ronald E. Talbert, John D. Mattice, Terry L. Law i Robert E. Frans. "Residual Fluometuron Levels in Three Arkansas Soils under Continuous Cotton (Gossypium hirsutum) Production". Weed Science 34, nr 1 (styczeń 1986): 122–30. http://dx.doi.org/10.1017/s0043174500026588.
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Evidence has shown that fluometuron {N,N-dimethyl-N′-[3-(trifluoromethyl)phenyl]urea} persists beyond the end of the growing season when used in continuous cotton (Gossypium hirsutumL.) production. Samples were taken from three soils following cotton production in 1980, 1981, and 1982. All three soils had been in production under the same herbicide use regime, fluometuron preemergence followed by fluometuron plus MSMA (monosodium methanearsonate), since either 1976 or 1977. The fluometuron remaining in each soil was quantified using a greenhouse bioassay and a chemical extraction technique followed by high-performance liquid chromatography determinations. The fluometuron concentrations determined by bioassay and chemical extraction methods had partial correlation coefficients of 0.62, 0.91, and 0.72 for a Sharkey silty clay, a Dundee silt loam, and a Loring silt loam, respectively. Predictive equations were determined for each soil to relate chemical extraction findings to plant response. Bioassay analysis indicated nearly 2 ppmw of fluometuron in the Sharkey silty clay in October 1980, with 1 ppmw in the Dundee silt loam, and approximately 0.27 ppmw in the Loring silt loam with annual application rates of 4.0, 2.9, and 3.5 kg/ha, respectively. Fluometuron concentrations as determined by chemical analysis were 0.83, 0.34, and 0.14 ppmw, respectively. Fluometuron concentrations declined over the winter in all three soils. Samples taken in March of 1981, 1982, and 1983 showed little difference in carryover levels in the Sharkey silty clay but more yearly variation in the other two soils. Fluometuron was found in all three soils to depths of 60 cm, but more than 55% of the fluometuron was found in the upper 15 cm of each soil. A controlled laboratory study conducted with the three soils showed that both cold and dry conditions reduced fluometuron dissipation rates. In the laboratory under conditions favorable for dissipation, fluometuron had a half-life of 26 days in the Dundee silt loam, 43 days in the Loring silt loam, and 73 days in the Sharkey silty clay. In the field, dissipation was very rapid in the Loring silt loam compared to the Dundee silt loam and the Sharkey silty clay.
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Nougar, Benali, Abdelkader Brahimi, Djamel Edddine Bouri, Abdallah Krim, Omar Safer, Kamel Menad i Ahmed Arab. "Application of the hypoplastic model for validating direct shear tests to investigate the impact of fines on the behavior of chlef sand". Journal of Engineering and Exact Sciences 10, nr 4 (27.05.2024): 18878. http://dx.doi.org/10.18540/jcecvl10iss4pp18878.
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This study was carried out to describe the mechanical behavior of different materials in terms of shear strength, cohesion and friction. For this purpose, an experimental shear tests were carried out. The soils used for the preparation of the samples were the Chlef sand, Chlef silt and M’zilla clay and a mixture composed of 50% of silt and 50% of clay. The soils were prepared by mixing Chlef sand with fines content of silt, clay or clay silt ranging from 0, 10, 20, 30 and 40%. The tests were conducted on sand samples prepared at a relative density of 20% representing a loose state and subjected to three normal stresses of 100, 200 and 400 kPa. All the tests were conducted at constant displacement rate of 1.00 mm/min. From the obtained results, it can be seen that the clean sand showed the highest shear strength at a small strains. At large strains, sands with 30% clay rather than 30% clay silt showed the highest shear strengths respectively. More contracted sands have the greatest increased maximum shear strengths. The sand with clayey silt, at a fine content of 20%, develops the most increased cohesion, among the other silty-clayey sands, together with the most reduced shear strength in elastic behavior. The sand with 40% of silt content develops a greater internal friction angle, however, the other silty sands, showed reduced shear strength, at the same behavior. To validate these findings, numerical simulations were performed on sand-silt mixtures using the hypoplastic model. The results indicated that the hypoplastic model accurately predicts the shear behavior of sand-silt mixtures in direct shear test, providing realistic insights into the effects of fines on the mechanical properties of the soil. Keywords: Sand, Silt, Clay, Fines Content, Shear Strength, Friction, Cohesion.
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Sezer, Alper, Eyyub Karakan i Nazar Tanrinian. "Shear modulus and damping ratio of a nonplastic silt at large shear strains". E3S Web of Conferences 92 (2019): 08007. http://dx.doi.org/10.1051/e3sconf/20199208007.
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Site response analyses and solution of dynamic soil-structure interaction problems need determination of variation of shear modulus and damping ratio with shear strain. Since many studies in literature concern evaluation of behavior of sands and silty sands, a series of cyclic triaxial tests were performed to determine the variation of shear modulus and damping ratio of a nonplastic silt with shear strain. Stress controlled cyclic triaxial tests on silt specimens of initial relative densities ranging among 30%, 50% and 70% were performed. Tests were carried out on identical samples under different CSR levels, and the confining pressure was selected as 100 kPa. Variation of shear modulus and damping ratio of silts with cyclic stress ratio amplitude, relative density and number of cycles were investigated. It was understood that soil relative density and cyclic stress ratio amplitude has a significant influence on shear modulus and damping ratio of silts. It was also observed that, as the cyclic stress ratio amplitude is increased, greater shear modulus and lower damping ratio values were obtained.
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Usman, Ediar, i I. W. Lugra. "Sediment Distribution related to Gold and Silver Placer Deposits in Offshore of Sambas Besar Estuary, Sambas Regency, West Kalimantan". Indonesian Journal on Geoscience 6, nr 1 (28.03.2011): 29–42. http://dx.doi.org/10.17014/ijog.6.1.29-42.
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DOI: 10.17014/ijog.v6i1.113Result of grain size analysis of the sea floor sediments from the study area indicates four sediment types, those are silt, sandy silt, silty sand, and sand. The silt unit has the widest distribution that is around 127.2 km2, sandy silt 12.65 km2, sand 1.176 km2, and silty sand 0.44 km2. Result of gold and silver content analysis from some selected samples indicates that the highest gold and silver amount are at PMK-08 location in northern part of the study area with gold content of 0.21 ppm and silver 13.36 ppm; both are silt sediment types. The highest gold and silver content occur within medium - coarse sediments containing subrounded grains of quartz and pyrite, at northern part of the study area. The presence of silver and gold is suggested to be controlled by a north-south longshore current pattern. The source of sediments from Sambas Besar River follows the longshore current, e.g. in northern estuary from south to north, and at southern estuary from north to south direction.
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Waroszewski, Jaroslaw, Tobias Sprafke, Cezary Kabala, Elżbieta Musztyfaga, Beata Łabaz i Przemysław Woźniczka. "Aeolian silt contribution to soils on mountain slopes (Mt. Ślęża, southwest Poland)". Quaternary Research 89, nr 3 (23.10.2017): 702–17. http://dx.doi.org/10.1017/qua.2017.76.
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AbstractThis paper evaluates the possible contribution of aeolian silt to soils of Mt. Ślęża (southwest Poland). Silt loam textures are common across Lower Silesia and are often confused with silt clay loam, especially at the outer boundaries with thin loess deposits. Eight study sites with different thicknesses of silt loam mantles that are covered and/or mixed with underlying sediments were examined in the field. To test our hypothesis, we analyzed the particle size and geochemistry of representative horizons. Concentrations of major and trace elements as well as their cross ratios confirmed the aeolian origin of silt loam materials and clearly distinguished them from basal sediments. There is a clear relationship between the presence and depth of aeolian mantles and mixing zones with the type of underlying material. Furthermore, the incorporation of aeolian silt to regoliths/soils was a main agent initiating and stimulating clay translocation leading to the formation of an argic horizon below the silt mantles. Mixing aeolian silt with acid granite regoliths and further illuviation resulted in the formation of alisols, while silt contributions to serpentine sediments resulted in development of skeletic luvisols. Soils receiving very weak input of aeolian silts remain as leptosols/cambisols.
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Sentani, A., Soedarsono i E. K. Soeridjal. "Fluid Behaviour Analysis on Liquefaction Using Korinofaction Device". IOP Conference Series: Earth and Environmental Science 955, nr 1 (1.01.2022): 012013. http://dx.doi.org/10.1088/1755-1315/955/1/012013.
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Abstract Earthquakes can be followed by liquefaction, which is a response of saturated soil when it is subjected to shock or stress that cause loss of soil strength or bearing capacity as an impact of the increasing of soil pore water and the loss of the soil stress’s effectiveness. This research using Korinofaction that work to cause cyclic loads or vibrations that come from DC servo motor with an adjustable speed and force. The earthquake’s strength is measured by the number of rpm measured on the digital tachometer. Korinofaction is equipped with plumbing system to observe fluid behaviour during liquefaction. The results of research showed that silty sand and silt was liquefied in VIII Modified Mercalli Intensity earthquake and cause the occurrence of water flow on the surface due to increase soil pore stress. The flow rate that triggers liquefaction in the silty sand is 6,769 × 10-5 m 3/ second ’ and silt is 5,0 × 10-5 m 3/ second . The water flow that flows in the silty sand had permeability of 4,76 × 10-4 Cm/second while on the silt is 6,09 × 10-4 Cm/second . After liquefaction, gradient hydraulic of silty sand is 4,76 mm and silt is 6,09 mm. Based on this research liquefaction caused mobilized debris flow and muddy debris flow.
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Hu, Ronghua, Ming Zhang i Jiaqi Wang. "An Investigation into the Influence of Sample Height on the Consolidation Behaviour of Dredged Silt". Applied Sciences 13, nr 18 (18.09.2023): 10419. http://dx.doi.org/10.3390/app131810419.
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This study delves into the effects of sample height on consolidation behaviour, utilising the automatic air pressure consolidometer. Extensive tests were conducted on three varieties of dredged silt samples of varying heights from Qianwan, Shenzhen, China. The salient findings can be summarised as follows: (1) Compression curves for samples of different dimensions transitioned through three distinct phases: minimal load disturbance, elastic deformation, and plastic deformation. Notably, the void ratio during the latter two phases diminished as sample height increased. (2) A rising sample height corresponded to a reduced stable strain and compression index. Furthermore, the consolidation coefficient notably diminished with an escalation in the sample height, whereas the structural yield stress remained largely unaffected. (3) Given the disparate formation processes, stress histories, and material compositions between dredged and marine silts, the permeability coefficient of dredged silt was found to be superior to that of marine silt. Within the typical preloading pressure scope (50~300 kPa), the consolidation coefficient of dredged silt was lower compared to marine silt. However, as the consolidation pressure significantly surpassed this threshold, the coefficient disparity between the two silts narrowed.
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Yamamuro, Jerry A., Fletcher M. Wood i Poul V. Lade. "Effect of depositional method on the microstructure of silty sand". Canadian Geotechnical Journal 45, nr 11 (listopad 2008): 1538–55. http://dx.doi.org/10.1139/t08-080.
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The results from a laboratory experimental study on silty sand are presented. A scanning electron microscope (SEM) was used to investigate the effect of depositional method and silt content on the grain contact structure of silty sand. Triaxial specimens containing Nevada sand with various quantities of nonplastic silt were isotropically consolidated to 25 kPa and then preserved through epoxy impregnation. Specimens were formed using both dry funnel deposition and water sedimentation. A procedure was developed that allowed the microstructure to be quantified in terms of potentially stable and unstable grain contacts. As silt content increased, the percentage of stable grain contacts decreased. Specimens formed by dry funnel deposition contained a higher percentage of potentially unstable grain contacts than those reconstituted by water sedimentation, possibly reflecting a more compressible particle structure. This effect became more pronounced as silt content increased. A description of the specimen preservation technique as well as the methodology used to both prepare and analyze SEM specimens for grain contact analysis are presented.
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Strehl, Eberhard. "Glazilimnische Kames in Schleswig-Holstein". E&G Quaternary Science Journal 48, nr 1 (1.01.1998): 19–22. http://dx.doi.org/10.3285/eg.48.1.02.
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Abstract. In the area of Weichselian glaciation in Schleswig-Holstein in the past years several occurrences of compared with their ein irons highly situated undisturbed basin sediments were found during geological mapping. Mostly occur silty clays, fine sand striped silts and silt striped fine sands, which during the ice decay were originally deposited in blanks in the glacier ice (dead ice), and became hills after the complete down melting of the glacier due to relief inversion. Three typical occurrences are described.
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Ringelberg, D. B., D. M. Cole, K. L. Foley, C. M. Ruidaz-Santiago i C. M. Reynolds. "Compressive strength of soils amended with a bacterial succinoglycan: effects of soluble salts and organic matter". Canadian Geotechnical Journal 51, nr 7 (lipiec 2014): 747–57. http://dx.doi.org/10.1139/cgj-2012-0369.
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The ability to stabilize soils in a cost effective and efficient manner has utility in both civil and military applications. This study examines the ability of a bacterial succinoglycan to bind and strengthen the silt fractions of three geochemically different surface soils. Small-scale specimen preparation and uniaxial compression test methods were developed to observe effects of biopolymer concentration and silt surface condition on specimen stress–strain response. Results indicate that the biopolymer was effective at strengthening all three natural silts and when applied at concentrations of 1–15 mg·mL−1, the increase in strength was linear. Silt surface condition was then modified by sequential removal of soluble salts and organic matter. For two of the silts, the removal of salts and organic matter had significant and cumulative negative effects on specimen compressive strength, deformation at peak stress, time to failure, and absorbed strain energy at failure. For a silt characterized by a high cation exchange capacity, high pH, and low aggregate percentage, the removal of organic matter did not reduce compressive strength beyond the level associated with the removal of soluble salts. Results from this study indicate that surface modification can significantly affect the compressive strength of silt materials and identified aggregate content as a principal determinant.
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Tang, Yan Chun, i Gao Tou Meng. "Excess Pore Pressure Dissipation Characteristics of Different Soil by CPTU on Pearl River Delta". Applied Mechanics and Materials 71-78 (lipiec 2011): 4606–9. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.4606.
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Through a lot of CPTU excess pore pressure dissipation tests on Pearl River Delta in China, excess pore pressure dissipation characteristics of different soil layer on Guangzhou-Zhuhai section of Beijing-Zhuhai Expressway and Taishan section of Guangdong West Coast Expressway has been analyzed. The dissipation time of 50% dissipation degree t50 of excess pore pressure dissipation curve by CPTU can be used as the auxiliary method to determine the type of soil, and through CPTU excess pore pressure dissipation tests, the t50 value of sand soil, silt, silty clay, clay soil and silt soil has been obtained; through comparison with the t50 value of different soil, the difference of sand soil, silt and clay soil can be roughly distinguished; the obvious boundary value between the t50 value of clay soil, silty clay and silt soil is not existed, so the t50 value can not be direct to determine the type of these clay type of soil. The achieved results can provide a research foundation for CPTU application research on Pearl River Delta in China.
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Wood, Fletcher M., Jerry A. Yamamuro i Poul V. Lade. "Effect of depositional method on the undrained response of silty sand". Canadian Geotechnical Journal 45, nr 11 (listopad 2008): 1525–37. http://dx.doi.org/10.1139/t08-079.
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The results from a laboratory experimental study on silty sand are presented. Undrained triaxial compression tests were performed on Nevada sand containing nonplastic silt. All specimens underwent monotonic loading after isotropic consolidation to 25 kPa. Various depositional techniques were used to create specimens to compare their stress–strain behavior within three separate density ranges and three different silt contents. As density increased, the effect of the depositional method on the undrained behavior decreased. The influence of the depositional method on specimen behavior also was found to increase with silt content, particularly at lower densities. These findings therefore are of special interest with regard to laboratory testing for the purpose of characterizing liquefaction potential, where loose, silty sands may be encountered. A description and analysis of five different depositional techniques is provided. These methods include: dry funnel deposition, water sedimentation, slurry deposition, mixed dry deposition, and air pluviation. The results of the undrained testing are analyzed using void ratio after consolidation and silt content as the bases of comparison.
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Shaw, David R., Stephen M. Schraer, Joby M. Prince, Michele Boyette i William L. Kingery. "Runoff losses of cyanazine and metolachlor: effects of soil type and precipitation timing". Weed Science 54, nr 4 (sierpień 2006): 800–806. http://dx.doi.org/10.1614/ws-05-095r1.1.
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The effects of time of precipitation and soil type on runoff losses of cyanazine and metolachlor were studied using a tilted-bed, microplot system. Two silt loam soils, Bosket and Dubbs, and a Sharkey silty clay were evaluated. Rainfall (22 mm h−1) was simulated at 0, 2, and 14 days after treatment (DAT). Time of precipitation did not impact herbicide losses or any of the runoff parameters evaluated in this study. Water runoff occurred sooner and in greater quantities from the surfaces of Bosket and Dubbs silt loam soils than from the surface of Sharkey silty clay. Runoff losses of cyanazine did not vary by soil type. Soil drying produced large cracks in Sharkey silty clay, which greatly reduced runoff in this soil. Combined runoff and leachate losses were highest from Dubbs silt loam. Runoff losses of metolachlor were not affected by soil type. However, regression analyses indicated that time of precipitation and soil type interacted to affect initial metolachlor concentration. At 14 DAT, initial metolachlor concentration was highest in runoff from Sharkey soil. Time of precipitation ranked with respect to initial metolachlor concentration in runoff from Bosket and Dubbs silt loam soils were 0 > 2 > 14 DAT and 0 = 2 > 14 DAT, respectively.
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Reddy, Krishna N., i Martin A. Locke. "Sulfentrazone sorption, desorption, and mineralization in soils from two tillage systems". Weed Science 46, nr 4 (sierpień 1998): 494–500. http://dx.doi.org/10.1017/s0043174500090950.
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Sulfentrazone sorption kinetics, desorption, and mineralization were evaluated in surface 7.5 cm of soils collected from long-term conventional-till (CT) and no-till (NT) plots. The soils used were Miami silt loam and Drummer silty clay loam from Illinois and Dundee silt loam from Mississippi. Sulfentrazone sorption kinetics in Dundee silt loam CT and NT soils were adequately described by a simple two-site equilibrium/kinetic model. Rapid initial sorption (within 1 h) was followed by a slower sorption and equilibrium, largely achieved by 72 h of shaking, with a negligible increase in sorption thereafter. The sorptionKfranged from 1.02 to 3.44 among the six CT and NT soils. TheKfvalues were greater for NT compared to their respective CT soils. Overall,Kfvalues were higher in Drummer silty clay loam followed by Dundee silt loam and Miami silt loam soil. TheNvalues were less than unity in all soils indicating nonlinear sorption. Sulfentrazone desorption was hysteretic with a very low rate of desorption. The total amount desorbed in four desorptions ranged from 58 to 72% of that sorbed. Less than 2.1% of applied14C-sulfentrazone was mineralized to14CO2 in Dundee silt loam CT and NT soils during a 77–d incubation. Relatively low mineralization of sulfentrazone suggests poor adaptability of native microbial populations that have not been exposed to this herbicide. Higher sorption and lower desorption of sulfentrazone in NT soils compared to CT soils suggest that NT systems (which tend to increase plant residues) may prolong sulfentrazone residence time in soil.
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A. Odundun, Olumuyiwa, Odunyemi A. Ademeso i Olusiji S. Ayodele. "INFLUENCE OF PARTICLE SIZE DISTRIBUTION AND MOISTURE CONTENT VARIABILITY ON THE CHARACTERIZATION OF SOILS IN IPINSA AREA, AKURE, SOUTHWESTERN NIGERIA". Geosciences Research Journal 1, nr 1 (2023): 15–21. http://dx.doi.org/10.26480/gsrj.01.2023.15.21.
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Distribution of different sizes of grains has always been useful in estimating other soil properties which will in turn help to understand soil mechanical behavior. Besides, the study area contains soil mass with layering structure which are similar to those exhibited by sedimentary rocks. Hence, the conventional sieve-hydrometer grain size analytical method and another grain size-based classification scheme were employed to characterize soil deposits found within the area of study. Results from this study showed that majority of soil samples are fine-grained. Moreover, silt fractions were found to hold a positive correlation with the effective sizes (D10) while the same could not be said of the sand and clay fractions due to their negative correlations with D10. Data from this study resulted in the zoning of soil into two categories namely; the clayey sandy silts (csSI) and clayey silty sands (csiS). Conditions under which the soils were deposited were deduced from the Silt Fraction (SF) versus Percentage Fines (PF) plot. The plots revealed that majority of the soils within the study area were deposited under low energy and intermediate conditions. A relationship was found to occur between moisture contents in the soil and their resulting zoning. Soils in the silt zone (csSI) have a better overall water content than soils in the sand zone (csiS).
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Nguyen, Minh Quang, Van Ha Vu, Thanh Tan Mai, Xuan Ban To, Ngoc Dien Tran, Minh Tuan Dang, Xuan Tung Dang, Thi Min Nguyen, Van Tha Hoang i Thi Kim Chi Giap. "Geomorphological sedimentary characteristics in the coastal area of Ma river delta, Thanh Hoa province". Tạp chí Khoa học và Công nghệ Biển 21, nr 3 (30.09.2021): 283–98. http://dx.doi.org/10.15625/1859-3097/15995.
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The coastal area of the Ma river delta is formed by the interaction of continental and marine processes, between neo-tectonic activities and exogenous processes, between natural factors and human activities during the Late Holocene. Using remote sensing and geoscience research methods (granulometry, paleontology, geochemistry, clay mineralogy) and geomorphological studies (geneses, morphology, dynamics) combined with field survey, this coastal area, except the denuded mountainous remnants, could be distinguished into 12 morpho-sedimentary units formed and developed by the dynamic interactions of the river, waves and tides. The units formed by fluvial dynamics include: 1) Point bar is composed of clayey silt and sandy silt, 2) Channel bar composed of silty sand, 3) Levee with the composition of silty sand and 4) The flood plain of silty clay. The Late Holocene evolution of the Ma river delta was dominated by wave dynamics, reflected by a wave-formed association of dunes, interdune swamps and current sand beaches. The wave-formed units include 5) Dune’s sand and silty sand, 6) Back-dune depressions composed of sand silt clay, 7) Beach composed of sand, 8) Lagoon plain of silty clay and 9) Strand plain composed of silty sand. The tide-influenced units include 10) Supratidal flat with the composition of silty clay, 11) Intertidal flat characterized by clay or silty clay interbedded with thin fine sand or silty sand layers, 12) Subtidal flat of sand and silty sand.
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Dahl, Karina R., Jason T. DeJong, Ross W. Boulanger, Robert Pyke i Douglas Wahl. "Characterization of an alluvial silt and clay deposit for monotonic, cyclic, and post-cyclic behavior". Canadian Geotechnical Journal 51, nr 4 (kwiecień 2014): 432–40. http://dx.doi.org/10.1139/cgj-2013-0057.
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This paper presents a detailed characterization of the monotonic, cyclic, and post-cyclic behavior of two strata within a recent Holocene alluvial deposit of silty sand, sandy silt, silt, and clay. Stratum A is composed predominantly of very soft clay and very loose silt with plasticity indices ranging from 5 to 27, whereas stratum B is composed predominantly of very loose silty sand and sandy silt with plasticity indices ranging from 0 to 10. Characterization included in situ testing, undisturbed soil sampling and laboratory testing, and a field surcharge test section. Consolidation tests and monotonic, cyclic, and post-cyclic direct simple shear tests were used to evaluate the effects of varying the consolidation stress, consolidation stress history, and initial static shear stress ratio. The field and laboratory test data show distinct differences in behavior between the two soil strata, which can be related to their different index test characteristics. These results are compared with their respective behaviors predicted using common engineering correlations. The field and laboratory test data summarized herein contribute to the database and understanding of the monotonic, cyclic, and post-cyclic behaviors of low-plasticity fine-grained soils.
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Moss, AJ. "Rain impact soil crust. IV. Packing of sand and silt fractions by raindrops". Soil Research 29, nr 2 (1991): 331. http://dx.doi.org/10.1071/sr9910331.
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Comparison of resistance to fast and slow deformation by rain-packed and artificially prepared sand and silt fractions showed that, whereas sands are left in loosely packed states after accrual under rain impact, silts are left more densely packed, i.e. below critical void ratio. This contrast is attributed mainly to the declining importance of hydraulic penetration with pore size. Rain-packed silt is dilatant and cannot deform without expansion which, in turn, requires water entry at a rate compatible with the required deformation. In the short duration of rain-impact events, hydrodynamic time lagging occurs because water can move only slowly through the small silt pores. Consequently, densely packed silt remains essentially rigid. However, drop-outflow sheets are able to entrain silt and distribute it over the surface as densely packed bed-load deposits, thus maintaining its dilatancy. Sand, its larger pores invaded by hydraulic penetration jets which maintain loose packing, cannot behave in this manner. Relative stability of the silt layer on soil surfaces, and its suppression of hydraulic penetration, allow transmission of drop-generated stress waves which cause the immediately underlying soil to become compacted into the main structural element of the rain-impact soil crust.
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Sun, Qiang, i Chao Lü. "Semiempirical correlation between thermal conductivity and electrical resistivity for silt and silty clay soils". GEOPHYSICS 84, nr 3 (1.05.2019): MR99—MR105. http://dx.doi.org/10.1190/geo2018-0549.1.
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Previous researchers have shown that thermal conductivity and electrical resistivity are related to the water content and void ratio of soil. The objective of this study is to present a theoretical relationship between these two physical parameters. A de Vries equation and Archie’s law are applied to develop a new theoretical equation that relates thermal conductivity to the electrical resistivity of soil. The DRE-2C thermal conductivity tester, which uses a transient plane-source method, is used to measure the thermal conductivity. In addition, the DDC-8 resistivity meter is used to measure the electrical resistivity. Experiments on the thermal conductivity and electrical resistivity of silt soil and silty clay soil with different gravimetric water contents and densities are performed. The results indicate that the theoretical equation can well explain the relationship between the thermal conductivity and electrical resistivity of silt and silty clay soils. The thermal conductivity and electrical resistivity are also found to have a linear relationship with the density of silt soil. When the gravimetric water content is less than 30%, the thermal conductivity and electrical resistivity of silty clay soil increase linearly with the density. The thermal conductivity increases with the gravimetric water content to a critical threshold depending on the soil type. The silty clay samples with a water content of 20% have the largest value of thermal conductivity. The electrical resistivity of the silt and silty clay samples decreases rapidly due to the increased pore connectivity and enhanced hydration of ions in soil with the increased water content. The results of the experiments indicate that the new theoretical equation is effective for estimating the soil electrical resistivity from the soil thermal conductivity.
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Wu, Lei, Qing Ling Ju, Hong De Wang, Jian Qing Wu i Chao Li. "Study on Physical Characteristics and the Optimal Moisture Content Control Technology of Compacted Silt Subgrade". Applied Mechanics and Materials 353-356 (sierpień 2013): 2908–12. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.2908.
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Through field test, physical and mechanical properties, mechanical composition, characteristics and compaction properties of the Yellow River alluvial silt soil were analyzed. The result shows that silt inside air compaction was difficult to discharge due to the influence of soil particle composition and low content of clay. As a result, the uneven settlement deformation of subgrade is obvious and the stability of silty soil water is not enough. The rainfall is frequent. Moisture content of soil is too high. It is difficult to dry field soil. The construction period is short. In order to speed up the pace of construction, we proposed the over-wet silt optimal multiple water control technology.
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Wang, Lili, Yunliang Li, Guizhang Zhao, Nanxiang Chen i Yuanzhi Xu. "Experimental Investigation of Flow Characteristics in Porous Media at Low Reynolds Numbers (Re→0) under Different Constant Hydraulic Heads". Water 11, nr 11 (6.11.2019): 2317. http://dx.doi.org/10.3390/w11112317.
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Understanding natural flows in porous media with low Reynolds number (Re) has significant implications for both science and engineering. However, knowledge and experimental gaps remain regarding such natural flows. In this context, we designed a sand column-based laboratory filtration experiment to investigate flow characteristics in porous media with low Re. Four media were considered including two silts (silt-I and silt-II), one silty sand, and one medium sand. Results show that constant hydraulic head is presumed to be an important factor that affects flow regime in porous media. In general, the flow approaches Darcian at a constant hydraulic head of ~170 cm, whereas it becomes non-Darcian at a constant hydraulic head of ~230 cm. The type of media determines the Re range that delimitates between Darcy and non-Darcy flows. Specifically, the transition appears at 0.015 < Re < 0.020 for medium sand and 0.000027 < Re < 0.000029 for silt-II, respectively. In the condition of constant hydraulic heads, the breakdown of Darcy’s law may occur at very low Re values (Re→0). Media dependent Re ranges are probably needed to describe the beginning of non-Darcy flows, rather than 1 to 10 or other value for all media. Findings in this study can offer insights into calculation and simulation of flows in low-permeability reservoirs, pumping process of foundation pit excavation, and other non-Darcy flows in low-permeability media.
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Arifah, S. N., H. M. Manik i D. S. Mulyadi. "Multibeam echosounder backscatter strength analysis for seafloor sediment identification in Damar Besar Island Waters, Thousand Islands". IOP Conference Series: Earth and Environmental Science 1251, nr 1 (1.10.2023): 012013. http://dx.doi.org/10.1088/1755-1315/1251/1/012013.
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Abstract The condition of the Indonesian territory surrounded by the ocean requires technology to obtain seabed information to support the development of social, economic, and security activities. One of the technologies that can be used is the multibeam echosounder (MBES) hydroacoustic technology. MBES can scan seabed in a wide range, resulting in bathymetric data and backscatter values. The value of backscatter can be used to identify seafloor sediments. This study compared backscatter intensity values obtained from the MBES survey to the previous study. After identifying the sediment, the data obtained are mapped to produce a sediment distribution map. The types of sediment identified in the Damar Besar Island Waters are fine silt, medium silt, coarsed silt, silty sand, muddy sand, clayed sand, very fine sand, and fine sand with a range of backscatter values from -34,92 to -19,04 dB. Fine sand sediments are nearby the northern island while muddy sands and silty sands are scattered away from the island.
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Ha, Vu Van, Doan Dinh Lam, Nguyen Thuy Duong, Nguyen Thi Thu Cuc, Nguyen Minh Quang, Hoang Van Tha, Nguyen Thi Min, Dang Minh Tuan, Dang Minh Tung i Giap Thi Kim Chi. "Holocene sedimentary facies in coastal plain of the Song Ma Delta, Thanh Hoa Province". VIETNAM JOURNAL OF EARTH SCIENCES 41, nr 3 (20.05.2019): 229–39. http://dx.doi.org/10.15625/0866-7187/41/3/13832.
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The Ma river delta located in the North Central of VietNam is the third largest ones in Vietnam following the Mekong Delta and the Red River Delta. However, there are not many researches on sedimentary. This study aims to determine the Characteristics of the Holocene sedimentary facies in coastal plain of the Song Ma Delta based on observation of sedimentary structure and analysis of grain size, diatom, flora, pollen and 14C dating collected for the drill core (LKTH2 borehole) from the coastal plain of the Song Ma river delta. Research results identify 08 facies consisting 02 facies of transgression period and 06 facies of regression period. During transgression period, 02 facies of tidal flat clayish silt and bay silty clay facies were formed. Of which, tidal flat clayish silt face was formed in 7,883 ± 43 14C yr BP. After the maximum flooding of the sea, the delta was initiated and 06 facies were formed during the regression period i.e. prodelta silty clay, delta front clayish silt, tidal flat sandy - silty clay, sand ridge, lagoonal sandy silty clay, and flood plain silty clay facies. The tidal flat sandy - silty clay facies occurred in 6.951± 38 14Cyr BP caused by sea level fall and the coastline was identified around the LKTH2 bore hole at that time. Integration of sedimentary facies of the sand ridge and lagoonal sandy silty clay facies shows that the Song Ma Delta was dominated by wave process during its evolution.
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Helfinalis, Helfinalis. "DISTRIBUSI SUSPENSI DAN SEDIMEN DI TELUK JAKARTA DAN PERAIRAN KEPULAUAN SERIBU". Jurnal Perikanan Universitas Gadjah Mada 7, nr 2 (3.08.2005): 128. http://dx.doi.org/10.22146/jfs.9068.
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The objectives of this study were to know total suspended solid (TSS) and sediment distributions in Jakarta bay and Seribu Islands waters. This study was conducted on 5-11 August 2003. Water samples for TSS measurement were taken from the water surface (2 m depth), 1 m upper the bottom surface, and in the middle of water column in each station. The highest TSS was found at 0.75 g/l on the water surface in front of the westside of Cengkareng drain. In Seribu Island waters, TSS was lower than 0.07 g/l. High TSS in the middle of water column were found in the north of Untung Jawa Island, Rambut Island waters, and north of Cengkareng drain. The highest TSS in the middle of water column reached 0.0324 g/l in surrounding Muara Angke waters. On the other hand, low TSSs in the middle of water column were found in the east of Untung Jawa Island and in the west of Rambut Island at around 0.0268 g/l. On the bottom, high TSSs were found in the most east of Bidadari and Karang Ubi Islands at 0.23 g/l. Low TSSs at around 0.02 g/l were found in the east and southeast of Untung Jawa Island and the north part of sampling location in this study. Silty mud sediment was observed in the northwest of Cengkareng drain estuary. In the surrounding Dadap and Kamal estuaries, silt, sandy silt, sand, and silty sand sediments were gradually found. Distribution of muddy sand sediment was found very narrow in the Jakarta Bay, but wider in the north of Tanjung Pasir. Silty sand, sand, sandy silt, and silt sediment were observed in the north part of sampling location in this study.The objectives of this study were to know total suspended solid (TSS) and sediment distributions in Jakarta bay and Seribu Islands waters. This study was conducted on 5-11 August 2003. Water samples for TSS measurement were taken from the water surface (2 m depth), 1 m upper the bottom surface, and in the middle of water column in each station. The highest TSS was found at 0.75 g/l on the water surface in front of the westside of Cengkareng drain. In Seribu Island waters, TSS was lower than 0.07 g/l. High TSS in the middle of water column were found in the north of Untung Jawa Island, Rambut Island waters, and north of Cengkareng drain. The highest TSS in the middle of water column reached 0.0324 g/l in surrounding Muara Angke waters. On the other hand, low TSSs in the middle of water column were found in the east of Untung Jawa Island and in the west of Rambut Island at around 0.0268 g/l. On the bottom, high TSSs were found in the most east of Bidadari and Karang Ubi Islands at 0.23 g/l. Low TSSs at around 0.02 g/l were found in the east and southeast of Untung Jawa Island and the north part of sampling location in this study. Silty mud sediment was observed in the northwest of Cengkareng drain estuary. In the surrounding Dadap and Kamal estuaries, silt, sandy silt, sand, and silty sand sediments were gradually found. Distribution of muddy sand sediment was found very narrow in the Jakarta Bay, but wider in the north of Tanjung Pasir. Silty sand, sand, sandy silt, and silt sediment were observed in the north part of sampling location in this study.
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Wang, Jingqiang, Zhengyu Hou, Guanbao Li, Guangming Kan, Baohua Liu, Xiangmei Meng, Qingfeng Hua i Lei Sun. "High-Frequency Dependence of Acoustic Properties of Three Typical Sediments in the South China Sea". Journal of Marine Science and Engineering 10, nr 9 (14.09.2022): 1295. http://dx.doi.org/10.3390/jmse10091295.
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The acoustic characteristics of three fine-grained sediments (silty sand, silt, silty clay) in the South China Sea (SCS) were measured and analyzed at high frequency range of 27–247 kHz. The measurement results show that the sound speed dispersion is a positive linear relation at the measured frequency range, and the attenuation follows nonlinear frequency dependence, α = kfn, where n ranges from 0.59 to 0.85 for the three different sediments in the SCS. The frequency dependence of sound speed and attenuation were compared with the published literature. It was found that for silty clay, clayey silt, silt, and silty sand, the dispersion characteristics of these four sediments are basically consistent; in general, the dispersion of coarse particles is significant, and that of fine particles is weak, and permeability is the key parameter that determines the inflection point of high frequency to low frequency. By modeling these sediments with the Biot–Stoll model, it was found that the Biot–Stoll model can better predict the frequency-dependent characteristics of sound attenuation in a high-frequency band under the matching constraints of sound speed dispersion characteristics, indicating that the Biot–Stoll model has good applicability to different types of sediments in a high-frequency band.
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Poch, Rosa Maria, Rafael Rodríguez-Ochoa, Octavio Artieda, Josep Carles Balasch i Jaume Boixadera. "Silt-sized sediments and gypsum on surface formations in the Ebro valley. A disambiguation of the term gypsiferous silts". Geologica Acta 19 (23.06.2021): 1–21. http://dx.doi.org/10.1344/geologiaacta2021.19.8.
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Since the 60’s, many authors have reported the presence of common silt-sized materials in the Ebro valley, on surface formations and positions that have given rise to several interpretations, sometimes contradictory. According to the references, three main terms are used (gypsiferous silts, loess and flour-like gypsum) applied to silts and fine sands with gypsum accumulations. The two first terms are applied to materials with carbonate contents up to 40-50%, coarse silty to fine sandy textures, and located in different positions. Loess normally appears as thick outcrops on slopes leeward from the main wind direction, with a limited pedogenesis consisting of a partial carbonate mobilisation and gypsum contents between 0 and 30%. The third (gypsum-rich) type has a variable spatial distribution, appearing between limestone layers, along footslopes, outcropping as metric surface formations, or as generalized karstified subsurface accumulations. Their composition is almost 100% silt- to fine sand size lenticular gypsum. While some authors claim for an aeolian origin to all these materials, only part of them (loess) has a clear aeolian origin, while flour-like gypsum derives from on-site weathering of gyprock or by precipitation of calcium- and sulfate saturated watertables as it is reported to occur in many other arid regions; and the rest (gypsiferous silts sensu stricto) are mainly colluvial-alluvial. This distinction is necessary since they differ in their geotechnical behaviour and properties relevant for agricultural land uses, therefore they should be taken into account when carrying out geological mappings or soil surveys in this and similar arid regions.
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Poch, Rosa Maria, Rafael Rodríguez-Ochoa, Octavio Artieda, Josep Carles Balasch i Jaume Boixadera. "Silt-sized sediments and gypsum on surface formations in the Ebro valley. A disambiguation of the term gypsiferous silts". Geologica Acta 19 (23.06.2021): 1–21. http://dx.doi.org/10.1344/geologicaacta2021.19.8.
Pełny tekst źródłaStreszczenie:
Since the 60’s, many authors have reported the presence of common silt-sized materials in the Ebro valley, on surface formations and positions that have given rise to several interpretations, sometimes contradictory. According to the references, three main terms are used (gypsiferous silts, loess and flour-like gypsum) applied to silts and fine sands with gypsum accumulations. The two first terms are applied to materials with carbonate contents up to 40-50%, coarse silty to fine sandy textures, and located in different positions. Loess normally appears as thick outcrops on slopes leeward from the main wind direction, with a limited pedogenesis consisting of a partial carbonate mobilisation and gypsum contents between 0 and 30%. The third (gypsum-rich) type has a variable spatial distribution, appearing between limestone layers, along footslopes, outcropping as metric surface formations, or as generalized karstified subsurface accumulations. Their composition is almost 100% silt- to fine sand size lenticular gypsum. While some authors claim for an aeolian origin to all these materials, only part of them (loess) has a clear aeolian origin, while flour-like gypsum derives from on-site weathering of gyprock or by precipitation of calcium- and sulfate saturated watertables as it is reported to occur in many other arid regions; and the rest (gypsiferous silts sensu stricto) are mainly colluvial-alluvial. This distinction is necessary since they differ in their geotechnical behaviour and properties relevant for agricultural land uses, therefore they should be taken into account when carrying out geological mappings or soil surveys in this and similar arid regions.
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Kuvaeva, Yu V. "THE GROUP COMPOSITION OF HUMUS AND FRACTIONS OF FINE-DISPERSED PHASE IN THE SODDY-PODZOLIC MEDIUM-LOAMY SOIL IN A LONG-TERM EXPERIMENT". Dokuchaev Soil Bulletin, nr 70 (30.12.2012): 18–42. http://dx.doi.org/10.19047/0136-1694-2012-70-18-42.
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The group composition of humus in microaggregates (colloidal, pre-colloidal, fine, medium and coarse silt) of the soddy-podzolic medium-loamy soil has been first studied in three five-course grain-tilled crop rotations in the long-term experiment of V.V. Dokuchaev Soil Science Institute. It is shown that in the trial with a higher dose of fertilizers (N150P150K180 kg/ha/year + 120 t/ha of manure) the humus content increases in soil after the first rotation as compared to that with average fertilizer doses (N60P60K60). This is explained by the content of carbon bond to microaggregates of medium and coarse silt. At the same time both experimental variants reveal deterioration of the microstructure including the decrease in the content of medium silt, accumulation of pre-colloidal and fine-dispersed fractions. It becomes evident that the best microstructure is observed in the variant enriched with fertilizer: it contains a great amount of silty fractions and humus components in the form of humates and nonhydrolyzed residues. Moreover, both experimental variants show a tendency towards decreasing the content of humates bond to silty fractions. The intensive system of fertilization in three rotations allowed maintaining the stable content of humus in the fraction of medium silt, the latter being disturbed to a lesser extent than that in the variant without manure application.
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Khomsin, Mukhtasor, Suntoyo, Danar Guruh Pratomo i Ahmad Ilmi Hudaya. "Seabed Sediment Classification using Multi-Frequency MBES Bathymetric and Its Features". IOP Conference Series: Earth and Environmental Science 1276, nr 1 (1.12.2023): 012067. http://dx.doi.org/10.1088/1755-1315/1276/1/012067.
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Abstract Principally, for a few decades, hydrographical surveys have been only to determine the depth of seawater. Sonar measurement tehcnology is the most widely used to conduct hydrographical surveys employing a singlebeam echosounder (SBES) and multibeam echosounder (MBES). In addition to depth information, seafloor sediment distribution maps are essential for port planning and management. In general, the distribution of seafloor sediments is predicted using backscatter data from SBES and MBES at single and multiple frequencies. The bathymetric data generated by the echosounder can be derived into several bathymetric features such as slope, ruggedness, roughness, aspect, bathymetric position index (BPI), and curvature. This study examines the possibility of using bathymetric measurement and bathymetric derivation of multi-frequency MBES to predict the distribution of seafloor sediments, especially in the harbor pond area. The study used a deep neural network (DDN) to classify the distribution of seabed sediments with bathymetric and bathymetric features input, validated with 74 in situ sediment samples (clayey sand, silt, sandy silt, and silty sand). Up to 75% of data sample sediments are used for training and 25% for validation. The classification results by DNN showed 42.6% clayey sand, 7.4% sandy silt, 46.7% silt, and 3.35% silty sand. The overall accuracy (AO) and Kappa classification of seabed sediments with DDN were 59.5% and 0.54 (moderate), respectively.
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Smith, Larry N. "Stratigraphic evidence for multiple drainings of glacial Lake Missoula along the Clark Fork River, Montana, USA". Quaternary Research 66, nr 2 (17.07.2006): 311–22. http://dx.doi.org/10.1016/j.yqres.2006.05.009.
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AbstractGlacial Lake Missoula, a source of Channeled Scabland flood waters, inundated valleys of northwest Montana to altitudes of ∼ 1265 m and to depths of >600 m, as evidenced by shorelines and silty lacustrine deposits. This study describes previously unrecognized catastrophic lake-drainage deposits that lie stratigraphically beneath the glacial-lake silts. The unconsolidated gravelly flood alluvium contains imbricated boulder-sized clasts, cross-stratified gravel with slip-face heights of 2–> 35 m, and 70- to 100-m-high gravel bars which all indicate a high-energy, high-volume alluvial environment. Gravel bars and high scablands were formed by catastrophic draining of one or possibly more early, high lake stands (1200–1265 m). Most glacial-lake silt, such as the Ninemile section, was deposited stratigraphically above the earlier deposits, represents a lower lake stand(s) (1050–1150 m), and was not deposited in lake(s) responsible for the highest discharge events. The glaciolacustrine silt-covered benches are incised by relict networks of valleys formed during the drainage of the last glacial lake. Significant erosion associated with the last lake draining was confined to the inner Clark Fork River canyon.
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Wang, Yan Fang, Zhi Gang Zhou i Zheng Yin Cai. "Studies about Creep Characteristic of Silty Clay on Triaxial Drained Creep Test". Applied Mechanics and Materials 580-583 (lipiec 2014): 355–58. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.355.
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The creep characteristic of saturated silty clay was studied by triaxial drained creep test through two stress paths of axial loading and lateral lightening. According to test data, some conclusions were submitted. First, the axial creep laws between the two stress paths were consistent on the drainage conditions. Volume strains were much smaller than axial strains. Volume strains presented shear dilatancy along with lightening confining pressure. The silty clay creep coefficient was put forward and its variation law was summarized. The silt soil creep coefficient was closely related to the deviatoric stress level. The two had a linear relationship. The silt soil creep coefficientincreased with deviatoric stress level and had no matter with the confining pressureand loading path.
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Miller, Barry B. "Screen-washing unconsolidated sediments for small macrofossils". Paleontological Society Special Publications 4 (1989): 260–63. http://dx.doi.org/10.1017/s2475262200005220.
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Screen-washing bulk samples of fossilliferous matrix is the method of choice for concentrating relatively large numbers of small fossils from unconsolidated sediments. The technique is most effective when used to disaggregate dry and unconsolidated sand, silt, and silty clay. Ideally, when the dry fossil-bearing particles will pass through an appropriate size screen-mesh, leaving behind a residue of fossils and coarser grain sizes. Organic-rich sediments, overconsolidated silt, silty clay, maris and clays may require soaking in dilute chemical solutions to encourage disaggregation. The extraction of fossils from these more intractable sediments, therefore, generally will be limited to the processing of quantitatively small samples (several hundred grams), in the laboratory.
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Jordan, David L., Patrick K. Bollich, Ann B. Burns i Douglas M. Walker. "Rice (Oryza sativa) response to clomazone". Weed Science 46, nr 3 (czerwiec 1998): 374–80. http://dx.doi.org/10.1017/s0043174500089566.
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Experiments were conducted in 1993 and 1994 to determine if seed treated with disulfoton at 3, 6, or 12 g ai kg−1 reduced bleaching of rice foliage caused by clomazone applied delayed preemergence at 0.56, 1.1, 1.7, or 2.2 kg ai ha−1 on silt loam and silty clay soils. Clomazone injured rice more on silt loam soil than on silty clay soil. Disulfoton reduced bleaching caused by clomazone. In additional field experiments conducted during 1995 and 1996, clomazone at rates as high as 2.2 kg ha−1 did not affect grain yield in seven of 10 experiments. Clomazone at rates below 1.7 kg ha−1 did not reduce grain yield in any of the experiments.
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Yang, Xiu Juan, i Tian Shun Hou. "Experimental Research on the Dynamic Pore Water Pressure’s Development Rules of the Silt in the Yellow River Delta, China". Advanced Materials Research 599 (listopad 2012): 659–63. http://dx.doi.org/10.4028/www.scientific.net/amr.599.659.
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Silt is the dominant soil in the deposited soil in the Yellow River Delta, with special properties. In this article, based on the results of the dynamic triaxial tests, the following conclusions are drawn. Under the cycle loading, the development of dynamic pore water pressure in silt differs from the sand, and its curve can be fitted by hyperbola. In beginning silty soils' pore water pressure rose sharply, and then gradually become stable, and in this paper the causes were analyzed.
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Guo, Tianqiang, i Shamsher Prakash. "Liquefaction of Silts and Silt-Clay Mixtures". Journal of Geotechnical and Geoenvironmental Engineering 125, nr 8 (sierpień 1999): 706–10. http://dx.doi.org/10.1061/(asce)1090-0241(1999)125:8(706).
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Bihs, Annika, Mike Long, Steinar Nordal i Priscilla Paniagua. "Consolidation parameters in silts from varied rate CPTU tests". AIMS Geosciences 7, nr 4 (2021): 637–68. http://dx.doi.org/10.3934/geosci.2021039.
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<abstract> <p>The interpretation of dissipation tests from cone penetration tests (CPTU) in silt is often considered challenging due to the occurrence of an unknown degree of partial consolidation during penetration which may influence the results significantly. The main objective of the present study is to investigate the influence of penetration rate and hence partial consolidation in silt deposits on the interpretation of consolidation parameters. Rate dependency studies have been carried out so as to give recommendations on how to establish design consolidation parameters in silts and consider the effect of partial consolidation on the development of design parameters. A comprehensive field and laboratory research program has been conducted on a silt deposit in Halsen-Stj?rdal, Norway. Alongside performing various rate penetration CPTU tests with rates varying between 0.5 mm/s and 200 mm/s, dissipation tests were executed to analyze the consolidation behaviour of the soil deposit. Furthermore, a series of soil samples have been taken at the site to carry out high quality laboratory tests. Correction methods developed for non-standard dissipation tests could be successfully applied to the silt deposit indicating partial consolidation. The results revealed an underestimation of the coefficient of consolidation if partial consolidation is neglected in the analysis, emphasizing the importance of considering the drainage conditions at a silt site thoroughly. To study the drainage conditions of a soil deposit a recently proposed approach has been applied introducing a normalized penetration rate to differentiate between drained and undrained behaviour during penetration. It is suggested that a normalized penetration rate of less than 0.1–0.2 indicate drained behaviour while a normalized penetration rate above 40–50 indicate undrained behaviour. Finally, available dissipation test data from a Norwegian Geo-Test Site (NGTS) in Halden, Norway have been used to successfully verify the recommendations made for silts.</p> </abstract>
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Wang, Wu Gang, Shu Wang Yan i Xiao Qiang Liu. "Experimental Research on Liquefaction Behavior of Saturated Silt in Anhui Area". Advanced Materials Research 261-263 (maj 2011): 943–46. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.943.
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The liquefaction for saturated silty foundation can be usually incurred under dynamic loading, such as vehicular loading and earthquakes. The silty soil liquefaction caused by earthquake is mostly the direct reason for the foundation invalidation and the structure collapse. To analyze the liquefaction behavior of saturated silty soil from Anhui Province under high seismic shock, a series of dynamic triaxial tests are carried out under the given density of remolded saturated silt with different confining pressure conditions varying from 1 m to 10 m depth in the laboratory. The increasing law of liquefaction resistance of the remolded saturated silt in Anhui province, dynamic intensity and the process of excess pore pressure are obtained from the dynamic triaxial test research. Meanwhile, the maximum liquefaction depth and the dynamic deformation properties are also illuminated based on dynamic triaxial tests, which can provide scientific data to further make engineering measures preventing the silty foundation from liquefying.
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Xu, Yao, Shu Cai Li, Xiao Zhang, Bin Yan i Chun Mei Zhu. "Dynamic Consolidation Test Study on Silt and Silt Soil". Applied Mechanics and Materials 90-93 (wrzesień 2011): 537–41. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.537.
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A dynamic consolidation model of double layered foundation of saturated soil and unsaturated soil is proposed. Mechanism of dynamic compaction treating on double layered foundation is studied by the model. On the base of the mechanism a new technology called soil-mound dynamic consolidation can be applied to treat the ground of saturated silt and silty clay with high groundwater level. The water-pore pressure test, static cone penetration test, settlement plate test are applied to evaluate that of the new technology with different construction parameters. The treatment effect is more remarkable than that of plastic drain-dynamic consolidation.
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Rogers, C. Brent, Ronald Talbert i Robert Frans. "Effect of Cotton (Gossypium hirsutum) Herbicide Carryover on Subsequent Crops". Weed Science 34, nr 5 (wrzesień 1986): 756–60. http://dx.doi.org/10.1017/s0043174500067813.
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The residual effect of three cotton (Gossypium hirsutumL.) herbicide programs, including the use of no herbicides, a minimum program consisting of fluometuron {N,N-dimethyl-N′-[3-(trifluoromethyl)phenyl] urea} and MSMA (monosodium salt of methylarsonic acid), and an intensive program consisting of trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine], fluometuron, MSMA, and linuron [N′-(3,4-dichlorophenyl)-N-methoxy-N-methylurea], were evaluated from 1976 to 1982. Herbicide injury to wheat (Triticum aestivumL.) and hairy vetch (Vicia villosaRoth.) on three soils showed carryover effects in the following sequence: Sharkey silty clay > Dundee silt loam > Loring silt loam. The intensive program was the most injurious on the Sharkey silty clay. The effects of the two herbicide programs were nearly equal on the Dundee and Loring silt loams. Possible replacement crops for cotton, such as grain sorghum [Sorghum bicolor(L.) Moench.] and corn (Zea maysL.) suffered the least damage from carryover; rice (Oryza sativaL.), soybeans [Glycine max(L.) Merr.] and cucumber (Cucumis sativisL.) suffered severe damage. Greenhouse bioassays generally confirmed field results, and fluometuron appeared to be the major component of carryover.
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Liang, Hong, Yan Wang, Tian Ping Zhou, Zhen Tao Zhang, Zhi Gang Li, Jin Fang Zhao i Te Rigele. "Dry and Wet Cycle Tri-Axial Test Research of Silt". Applied Mechanics and Materials 90-93 (wrzesień 2011): 41–43. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.41.
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Abstract. Silt in some areas of our country is very extensive, its distribution is different from the cohesive soil, or sand soil, has unique engineering characteristic. Silt regional characteristics make it has many unique physic-mechanical performance. This article take the G209 (Inner Mongolia Helin to Qingshuihe section) the roadbed silty soil as the study object, study its basic physics, the mechanical properties as well as the distortion and the intensity change rule under the dry-wet circulation, do a comprehensive and systematic analysis about varieties of basic engineering characteristic of the silt in the region Through the condition of dry-wet circulation of unconsolidated tri-axial tests, this article study the silt sample failure pattern under different degree of compaction, stress-strain relations and the change rule of strength. The test results show that: as cycle index less and confining pressure down, test sample is basically brittle failure, on the contrary case, it is behaved for plastic failure and stress-strain curve is close to sclerosis type; When cycle index increase gradually, the cohesion of silt reduced significantly ,with the increase of dry-wet circulation times internal friction angle is on the trend of the attenuation oscillation ; On this basis, we build the relationship expression of shear strength parameters cohesion internal friction angle and dry-wet circulation times.
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Ritson, Katie. "Silt". Environmental Humanities 11, nr 2 (1.11.2019): 461–64. http://dx.doi.org/10.1215/22011919-7754556.
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Gray, D. M., i R. J. Granger. "In situ measurements of moisture and salt movement in freezing soils". Canadian Journal of Earth Sciences 23, nr 5 (1.05.1986): 696–704. http://dx.doi.org/10.1139/e86-069.
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The paper presents the results of field studies on the movement of moisture and salts during freezing of Prairie soils. It is shown that large fluxes of water can migrate to the freezing front and move upward into the frozen soil above. The fluxes are largest in light-textured soils (e.g., silt loam) having a water table at shallow depth. However, substantial amounts of soil moisture may also move in silty clay, silty clay loam, and clay soils under dryland farming provided there is sufficient water present to support capillary flow.The dynamics of soil moisture transfer under natural conditions as a result of freezing involves movement of water in both vapor and liquid phases. In the shallow surface layer of soil, to a depth of 300–400 mm, vapor flow predominates; in the depth below, water usually moves primarily as a liquid. It is demonstrated that the accumulation of ice with time increases because of the downward movement of the freezing front and the upward movement of water into the frozen soil above. In a silt loam with large fluxes, the ice content of the frozen zone rapidly reaches a level (80–85% pore saturation) where measurable migration ceases. Conversely, in a silty clay the movement of moisture into the frozen soil is observed to continue throughout most of the freezing period, and the ice content reaches 93% pore saturation. The greater movement in the finer grained soil is attributed to a higher freezing-point depression, a larger number of capillary pores, and a higher concentration of soluble salts in the liquid films.A close association is observed between changes in the ice content and electrical conductivity of a silt loam after freezing. In a silty clay the agreement is less clear, probably the result of the exchange of ions between the migrating liquid water and the clay particles. Maximum amounts of exchangeable ions moving into a 1 m depth of soil by the freezing action are estimated to be 11.9 t/ha in a silt loam and 15.7 t/ha in a silty clay loam.Data showing the redistribution of water and salts during thawing are also presented and discussed.
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Yang, Jiu Jun, Lei Zhang, Pu Guo i Xue Ping Wang. "Investigation on Mechanical Properties of Clay-Based Material Prepared from the Yellow River Silt". Applied Mechanics and Materials 152-154 (styczeń 2012): 624–29. http://dx.doi.org/10.4028/www.scientific.net/amm.152-154.624.
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The Yellow River silt is a kind of sedimentary sandy soil which comes from the loess plateau carried by the steam of Yellow River. In order to utilizing silt and saving resource, investigation and analysis of characteristics Yellow River silts from the lower reaches area were performed, and clay-based cementitious material were prepared from Yellow River silt as main raw material, and a few of cement, lime and excitant agent as auxiliary materials. The mechanical properties and water resistances of clay-based cementitious material were studied. The results shows that: The clay-based cementitious material which is activated by composite excitant agent composed of sodium hexametaphosphate, calcium chloride and sodium silicate, have favorable mechanical and physical properties, especially favorable water-resistance. The specimen compressive strength is 21.2MPa after curing for 28d and with a softening coefficient 0.78, which cement content is 10% and excitant agent content is 4%.
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Zhao, Weiguo, Xiangdong Han, Rennian Li, Yingjie Zheng i Yanyan Wang. "Effects of size and concentration of silt particles on flow and performance of a centrifugal pump under cavitating conditions". Modern Physics Letters B 31, nr 34 (6.12.2017): 1750312. http://dx.doi.org/10.1142/s0217984917503122.
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To research effects of silt particles on the performance and cavitation flow fields, silt-laden cavitation flow was simulated in the centrifugal pump. Silt mean diameters are 0.005 mm and 0.010 mm and silt concentrations are 0.5% and 1.0%. Results show that silt particles with silt mean diameter 0.005 mm and silt concentration 1.0% and silt particles with silt mean diameter 0.010 mm and silt concentration 0.5% promote the development of cavitation and distribution range of vapor is larger than pure water. Effects of silt particles and cavitation make distribution range of turbulent kinetic energy larger than pure water and streamlines are more disorderedly. Silt particles with silt mean diameter 0.010 mm and silt concentration 1.0% have little effect on cavitation and distribution range of vapor is similar with pure water. Effects of silt particles make distribution range of turbulent kinetic energy larger than pure water and streamlines are more disorderedly than pure water. With the increase of silt mean diameter and silt concentration, head and efficiency decrease gradually. For silt particles promoting the evolution of cavitation, distribution range of turbulent kinetic energy is larger and streamlines are more disorderly than silt-laden cavitation flow with silt particles inhibiting the development of cavitation.