MODEL Test and Study of Vertical Loading Single Pile in Transversely Isotropy Clay

2011 ◽  
Vol 368-373 ◽  
pp. 85-88
Author(s):  
Zan Cheng Zhu ◽  
Feng Hua Jiang ◽  
Xiao Gang Wang
Keyword(s):  
Similarity Theory ◽  
Soil Surface ◽  
Test Point ◽  
Vertical Loading ◽  
Transversely Isotropy ◽  
Exciting Frequency ◽  
Transverse Isotropic ◽  
The Moment ◽  
Pile Model ◽  
Variation Trends

According to the basic idea of similarity theory, the pile model in saturated transverse isotropic clay is determined. It imitates the moment of different positions along the pile and acceleration of each test point on the soil surface, under the same largest exciting force with different frequencies on the top of the pile. The results of experiment show that the variation trends of the moment are the same for different frequencies of excitation, looking like an inverse S. Acceleration value of each test point on the soil surface decreases with decline of the exciting frequency.

Model Test and Study on Pile Foundation in Transversely Isotropy Clay

2011 ◽  
Vol 105-107 ◽  
pp. 1380-1384
Author(s):  
Zan Cheng Zhu ◽  
Fan Bo Guo ◽  
Feng Hua Jiang ◽  
Xiao Gang Wang
Keyword(s):  
Pile Foundation ◽  
Similarity Theory ◽  
Soft Clay ◽  
Plane Curve ◽  
Soil Surface ◽  
Test Point ◽  
Foundation Soil ◽  
Transversely Isotropy ◽  
Hyperbolic Curve ◽  
Shock Frequency

To further verify the feasibility of theoretic calculation, according to similarity theory, the principles and methods of pile foundation-soil interaction in saturated soft clay are determined. It studies acceleration interaction of each test point on the soil surface under the same largest shock force with different frequency on the top of the pile. The results of experiment show that the acceleration interaction trend of each point changes with the change of shock frequency, it shapes like a down N with the shock frequency of 5Hz, like an M with the shock frequency of 10Hz, like a down V under the shock frequency of 15Hz～30Hz. With the shock frequency of 40Hz and 50Hz, it likes a plane curve (hyperbolic curve) shape.

Research on Negative Skin Friction on Pile by a Simple Model Experiment

2014 ◽  
Vol 580-583 ◽  
pp. 693-696
Author(s):  
Ting Huang ◽  
Jin Hai Zheng ◽  
Wei Ming Gong
Keyword(s):  
Skin Friction ◽  
Model Test ◽  
Soil Surface ◽  
Test Methods ◽  
Negative Skin Friction ◽  
Experimental Scheme ◽  
Test Conditions ◽  
Surcharge Load ◽  
Conventional Test ◽  
Pile Model

Accompanied by the substantive construction of domestic ports, the negative skin friction on pile becomes a common problem. In order to provide references for the related experiment research in the future, the designs of model experiments reported in the literatures were emphatically analyzed and compared. Compared to conventional pile model test, the model test on negative skin friction on pile needs to apply load on soil surface and it is difficult to simulate large surcharge by conventional test methods. An experimental scheme which could produce large surcharge load by conventional test conditions is given in this paper. Pile stress, displacement of pile top and layered settlement of soil was tested under different surcharge level. The depth of neutral point and the group effect of NSF are discussed.

scholarly journals The effect of the load of a combustion engine on energetic and performance parameters of tractor aggregates

2009 ◽  
Vol 57 (2) ◽  
pp. 155-166
Author(s):  
Milan Vojáček ◽  
František Bauer ◽  
Pavel Sedlák ◽  
Tomáš Šmerda
Keyword(s):  
Diesel Fuel ◽  
Combustion Engine ◽  
Spring Barley ◽  
Soil Layer ◽  
Soil Surface ◽  
Fuel Saving ◽  
Efficiency Performance ◽  
And Performance ◽  
The Moment ◽  
The One

The objective of this paper is to demonstrate possibilities how to reduce consumption of Diesel fuel on the one hand and to increase the performance of tractor aggregates on the other. Measurings were performed on a field with clayey-loamy soil, after the harvest of spring barley as forecrop and treatment of soil surface with disc harrowing. At the moment of measuring, the upper soil layer (till 10 cm) contained 16.5 % of humidity. Measured were the following parameters: consumption of Diesel fuel, engine revolutions, total time of ploughing, time of turning, depth of ploughing, and the swath of tractor aggregate. The specific consumption of diesel fuel Qm,1 and the efficiency (performance) of the aggregate W1 were calculated using the aforementioned parameters. The experimental tractor operated always with the full dose of fuel. Measurings were performed within zones A – economic revolutions of the engine (1 580–1 800 min−1) and B – maximum working revolutions of the engine (1 800–2 000 min−1). Basing on measured values it was found out that in zones A and B, the ploughing aggregate Case Magnum MX 285 plus a combined cultivator Köckerling Exaktgrubber – Vario showed 9.1 % of fuel saving. Values of efficiency increased by 11.5%. For the ploughing aggregate Case Magnum MX 285 plus the disc harrow Väderstad Excellent XT 620 the corresponding fuel saving was 17.2 %) while the value of efficiency increased by 7.2 %).

Movement of Water Across Soils (Erosion)

1999 ◽  
Author(s):  
Robert F. Keefer
Keyword(s):  
Land Surface ◽  
Grand Canyon ◽  
Soil Surface ◽  
Bare Soil ◽  
Surface Flow ◽  
Running Water ◽  
Soil Particles ◽  
The Moment ◽  
New Location ◽  
Sheet Erosion

Erosion is the physical wearing away of the land surface by running water, wind, or ice. Soil or rock is initially detached by falling water, running water, wind, ice or freezing conditions, or gravity. Movement of the rock or soil may follow. Erosion is the combination of detachment and movement of soil or rock. Water erosion can be subdivided into either natural or man-made. Natural or geologic erosion does not require the presence of man. This process has been going on from the moment that land masses were uplifted. An example of geologic erosion is the Grand Canyon in Arizona. Man-made erosion is also called “accelerated erosion” as it is more rapid than natural erosion. Changes that man or animals have made to the soil by cultivation, construction, or any movement of earth often result in loss of soil by erosion. Accelerated erosion involves raindrop erosion, sheet erosion, surface flow, and landscapes. For raindrop erosion to occur, there must be detachment of soil particles followed by either transportation or compaction. Sheet erosion is the slow wearing away of the surface of soil. Surface flow occurs when sufficient water collects to run downhill, resulting in small soil cuts (rills) that often develop into large ruts (gullies). Landslides or slips occur when large chunks of soil move as a unit downhill, often resulting in drops of several feet or more. As rain falls, the drops strike the soil surface moving the soil particles with energy being expended in three kinds of ways: (a) detachment— soil particles are broken into smaller pieces, (b) transportation— small soil grains are moved to a new location as they splash into the air; movement can be downward, to sides, or up eventually acting as a smoothing agent, or (c) compaction—raindrops compact soil surface on bare soil forming a crust, resulting in running the soil particles together (puddling) so that air and water can no longer enter the soil. This causes loss of infiltration and results in runoff.

scholarly journals The effect of soil redistribution on soil organic carbon: an experimental study

2010 ◽  
Vol 7 (12) ◽  
pp. 3971-3986 ◽  
Author(s):  
H. Van Hemelryck ◽  
P. Fiener ◽  
K. Van Oost ◽  
G. Govers ◽  
R. Merckx
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Initial Conditions ◽  
Soil Surface ◽  
Co2 Efflux ◽  
Soil System ◽  
Soil Material ◽  
Soil Redistribution ◽  
Undisturbed Soils ◽  
The Moment

Abstract. Soil erosion, transport and deposition by water drastically affect the distribution of soil organic carbon (SOC) within a landscape. Furthermore, soil redistribution is assumed to have a large impact on the exchange of carbon (C) between the pedosphere and the atmosphere. There is, however, significant scientific disagreement concerning the relative importance of the key-mechanisms at play. One of the major uncertainties concerns the fraction of SOC that is mineralized when soil is eroded by water, from the moment when detachment takes place until the moment when the SOC becomes protected by burial. In this study, the changes in C-exchange between soil and atmosphere as affected by soil redistribution processes were experimentally quantified. During a laboratory experiment, three types of erosional events were simulated, each of which was designed to produce a different amount of eroded soil material with a different degree of aggregation. During a 98-day period, CO2-efflux was measured in-situ and under field conditions on undisturbed soils with a layer of deposited soil material. Depending on the initial conditions of the soil and the intensity of the erosion process, a significant fraction of eroded SOC was mineralized after deposition. However, results also suggest that deposition produces a dense stratified layer of sediment that caps the soil surface, leading to a decrease in SOC decomposition in deeper soil layers. As a result, the net effect of erosion on SOC can be smaller, depending on the functioning of the whole soil system. In this study, soil redistribution processes contributed an additional emission of 2 to 12% of total C contained in eroded sediment.

Model Tests Research on Extruding Soil Caused by Close-Mouth Step Cross-Section Pipe Pile

2015 ◽  
Vol 744-746 ◽  
pp. 531-535
Author(s):  
Qing Guang Yang ◽  
Jie Tian ◽  
Jie Liu ◽  
Ya Hui Wang
Keyword(s):  
Cross Section ◽  
Soil Surface ◽  
Average Diameter ◽  
Horizontal Displacement ◽  
Penetration Resistance ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Pipe Pile ◽  
Uniform Cross Section ◽  
Pile Model

To study extruding soil caused of close-mouth step cross-section pipe Pile, model experimentals of five static piling tests with two constant cross-section pipe piles and three step cross-scetion pipe piles are performed in lab respectively and some observation points are installed for heave amount and horizontal displacement of soil surface around piles before tests.Results show that penetration resistance improved linearly with increasing of length of pile in soil and there has a turning point which become more and more obviously with increasing of average diameter of step cross-section pipe pile after the pile length in soil is 70cm.Comparing with uniform cross-section pipe pile, penetration resistance per unit volume is more bigger and increases with improving of variable cross-section ratio to step cross-section pipe pile.The swelling-up amount of soil around step cross-section pipe pile increases firstly, then decreases secondly ,and increases finally. Camparing with uniform cross-section pipe pile, the maximum heaves have 51.0% and 44.6% reduce respectively to setp cross-section pipe pile and the position of largest heaves moved from 1.0d to 1.5d.Moreover, the largest horizontal displacements have 24.6% and 26.9% reduce respectively to step cros-section pipe pile and the point of largest horizontal displacement moved from 2.0d to 2.5d.

scholarly journals The effect of soil redistribution on soil organic carbon: an experimental study

2009 ◽  
Vol 6 (3) ◽  
pp. 5031-5071 ◽  
Author(s):  
H. Van Hemelryck ◽  
P. Fiener ◽  
K. Van Oost ◽  
G. Govers
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Initial Conditions ◽  
Soil Surface ◽  
Co2 Efflux ◽  
Soil System ◽  
Soil Material ◽  
Soil Redistribution ◽  
Undisturbed Soils ◽  
The Moment

Abstract. Soil erosion, transport and deposition by water drastically affect the distribution of soil organic carbon (SOC) within a landscape. Furthermore, soil redistribution is assumed to have a large impact on the exchange of carbon (C) between the pedosphere and the atmosphere. There is, however, significant scientific disagreement concerning the relative importance of the key-mechanisms at play. One of the major uncertainties concerns the fraction of SOC that is mineralized when soil is eroded by water, from the moment when detachment takes place until the moment when the SOC becomes protected by burial. In this study, the changes in C-exchange between soil and atmosphere as affected by soil redistribution processes were experimentally quantified. During a laboratory experiment, three types of erosional events were simulated, each of which was designed to produce a different amount of eroded soil material with a different degree of aggregation. During a 98-day period, CO2-efflux was measured in-situ and under field conditions on undisturbed soils with a layer of deposited soil material. Depending on the initial conditions of the soil and the intensity of the erosion process, a significant fraction of eroded SOC was mineralized after deposition (between 14 and 22%). However, results also suggest that deposition produces a dense stratified layer of sediment that caps the soil surface, leading to a decrease in SOC decomposition in deeper soil layers. As a result, the net effect of erosion on SOC can be smaller, depending on the functioning of the whole soil system. In this study, soil redistribution processes contributed an additional emission of 2 to 12% of total C contained in eroded sediment.

scholarly journals First Report of Southern Blight Incited by Sclerotium rolfsii on Potato (Solanum tuberosum) in Northern Italy

Plant Disease ◽  
2006 ◽  
Vol 90 (8) ◽  
pp. 1114-1114 ◽  
Author(s):  
A. Garibaldi ◽  
G. Gilardi ◽  
M. L. Gullino
Keyword(s):  
Solanum Tuberosum ◽  
Solanum Tuberosum L ◽  
Sclerotium Rolfsii ◽  
Soil Surface ◽  
The United States ◽  
Northern Italy ◽  
Strong Increase ◽  
Southern Blight ◽  
White Mycelium ◽  
The Moment

During the summer of 2005, plants of potato (Solanum tuberosum L.) showing severe basal rot symptoms were observed in a commercial field near Alessandria (northern Italy). The first symptoms were detected during early July in correspondence with a strong increase of air temperature (as much as 38°C, with an average monthly increase of 10°C) and relative humidity. Infected plants showed dry collar rots and extensive necrosis of cortical tissues. Leaves of infected plants were chlorotic. As the disease progressed, tubers rotted and plants wilted. Infected plants appeared in patches, encompassing 10 to 15% of the cultivated area. In the presence of abundant moisture, a white mycelium occurred on infected tissues. On their surface, infected tubers showed a fan-like mycelial growth. Later, white or light-to-dark brown sclerotia (2 to 4 mm in diameter) developed from mycelium. Clamp connections were present. The diseased tissue was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 mg/liter of streptomycin sulfate. Sclerotium rolfsii was consistently isolated from infected plants. Pathogenicity of one isolate obtained from infected plants was confirmed by inoculating healthy S. tuberosum plants (cv. Hermes) grown in 2:l volume pots (1 plant per pot, seven replicates). Inoculum that consisted of 1 g/pot of wheat kernels infested with mycelium and sclerotia was placed on the soil surface. Seven noninoculated plants served as controls. The inoculation trial was repeated once. Plants were kept at temperatures ranging between 25 and 32°C and watered as needed. Inoculated plants developed symptoms of leaf yellowing within 10 days, soon followed by the appearance of white mycelium and sclerotia and then eventually wilted. Control plants remained symptomless. Sclerotium rolfsii was reisolated from inoculated plants.Possible attacks of Sclerotium rolfsii on S. tuberosum were described as rarely occurring in southern Italy (3). The disease, detected at the moment in very few farms and on cvs. Hermes and Monalisa, was particularly severe on the last variety, causing 5 to 15% yield losses because of premature plant death and rotting of tubers. This disease has been reported in several countries such as India (1), Israel (2), and the United States of America (4). References: (1) N. S. Bisht. Indian Phytopathol. 35:148, 1982. (2) Y. Elad et al. Soil Biol. Biochem. 16:381, 1984. (3) R. Gigante. Ital. Agric. 87:263, 1946. (4) G. F. Weber. Phytopathology, 33:615, 1943.

scholarly journals SOIL ARCHING AND LOAD TRANSFER MECHANISM FOR SLOPE STABILIZED WITH PILES

2012 ◽  
Vol 18 (5) ◽  
pp. 701-708 ◽  
Author(s):  
Mehmet Rifat Kahyaoglu ◽  
Okan Onal ◽  
Gökhan Imançlı ◽  
Gürkan Ozden ◽  
Arif S. Kayalar
Keyword(s):  
Load Transfer ◽  
Soil Surface ◽  
Time Lapse ◽  
Pile Head ◽  
Soil Pressure ◽  
Soil Arching ◽  
Recording Time ◽  
Pile Spacing ◽  
Stabilizing Piles ◽  
The Moment

In this study, the effects of pile spacing and pile head fixity on the moment and lateral soil pressure distribution along slope stabilizing piles are investigated. A slice from an infinitely long row of piles with fixed pile tip in an inclined sand bed was simulated with an experimental test setup. Surficial soil displacements were monitored and relative displacements between soil particles were determined by recording time-lapse images during the test in order to observe the soil arching mechanism on the soil surface. The load transfer process from moving soil to piles and behavior of soil around piles were observed and evaluated by the different test setups. It was observed that decrease in pile spacing causes an increase of load carried per pile. This behavior, which was significantly influenced by the pile head boundary conditions, can only be explained by soil arching that existed between the piles along their lengths.

scholarly journals First Report of Sclerotinia sclerotiorum on Argyranthemum frutescens in Italy

Plant Disease ◽  
2008 ◽  
Vol 92 (8) ◽  
pp. 1250-1250 ◽  
Author(s):  
A. Garibaldi ◽  
P. Pensa ◽  
M. L. Gullino
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Soil Surface ◽  
Its Region ◽  
Northern Italy ◽  
First Report ◽  
Potted Plants ◽  
Inoculation Trial ◽  
Leaf Yellowing ◽  
Stem Necrosis ◽  
The Moment

Paris daisy (Argyranthemum frutescens (L.) Sch. Bip.) is an economically important crop on the Riviera Ligure (northern Italy), where approximately 10 million plants per year are produced for export. In the winter of 2007, extensive wilting was observed on 5-month-old potted plants of A. frutescens grown in a commercial greenhouse near Albenga. First symptoms included stem necrosis, darkening and withering of leaves, and wilting of young buds. As stem and foliar necrosis progressed, infected plants wilted and died. Wilt occurred a few days after the appearance of the first symptoms. Infected plants were characterized by the presence of soft, watery tissues. Lesions became covered with a whitish mycelium and dark sclerotia were produced on the mycelium. Diseased stem tissue was surface sterilized for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 mg/l streptomycin sulfate. Sclerotinia sclerotiorum (Lib.) de Bary (2) was consistently recovered from infected stem pieces. Sclerotia produced on PDA measured 1.4 to 5.2 × 2.3 to 6.7 (average 3.3 to 4.2) mm. The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and then sequenced. BLAST analysis (1) of the 531-bp segment showed a 100% homology with the sequence of S. sclerotiorum. The nucleotide sequence has been assigned GenBank Accession No. EU 556701. Pathogenicity of two isolates obtained from infected plants was confirmed by inoculating 10 90-day-old plants for each isolate. Plants were grown singly in 18-cm-diameter pots maintained in a greenhouse under shade and were regularly irrigated and fertilized. Mycelium plugs 1 cm2 were excised from a 10-day-old PDA culture of both isolates and placed on the soil surface around the base of each plant. Ten noninoculated plants served as controls. Plants were maintained in a greenhouse under shade at temperatures ranging between 6 and 22°C (average 18°C) and relative humidity at >90%. The inoculation trial was carried out twice. All inoculated plants developed leaf yellowing by 22 days after inoculation. White, cottony mycelium and black sclerotia developed on stems and at the base of all inoculated plants. Eventually, infected plants wilted. Control plants remained symptomless. S. sclerotiorum was reisolated from the stems of inoculated plants. To our knowledge, this is the first report of S. sclerotiorum causing white mold on A. frutescens in Italy as well as worldwide. The economic importance of this disease can be considered limited at the moment. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997 (2) N. F. Buchwald. Kongl. Veterisk Landb. Aarssk. 75, 1949.

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