Breaching of levees: An erosion model that takes into account the soil tensile strength

2014 ◽  
pp. 419-425 ◽  
Author(s):  
Z Liu ◽  
Stéphane Bonelli ◽  
Fabienne Mercier
Keyword(s):  
Tensile Strength ◽  
Erosion Model ◽  
Soil Tensile Strength

Investigating the correlation between soil tensile strength curve and soil water retention curve via modeling

2017 ◽  
Vol 167 ◽  
pp. 9-29 ◽  
Author(s):  
Golnaz Ebrahim-Zadeh ◽  
Hossein Bayat ◽  
Ali Akbar Safari Sinegani ◽  
Hamid Zare Abyaneh ◽  
Harry Vereecken
Keyword(s):  
Tensile Strength ◽  
Soil Water ◽  
Water Retention ◽  
Water Retention Curve ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Retention Curve ◽  
Strength Curve ◽  
Soil Tensile Strength

scholarly journals Effect of discrete fibre reinforcement on soil tensile strength

2014 ◽  
Vol 6 (2) ◽  
pp. 133-137 ◽  
Author(s):  
Jian Li ◽  
Chaosheng Tang ◽  
Deying Wang ◽  
Xiangjun Pei ◽  
Bin Shi
Keyword(s):  
Tensile Strength ◽  
Fibre Reinforcement ◽  
Soil Tensile Strength

Vegetation effects on the tensile strength of a partially saturated soil

2021 ◽  
Author(s):  
Alessandro Fraccica ◽  
Enrique Romero ◽  
Thierry Fourcaud
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Water Content ◽  
Silty Sand ◽  
Degree Of Saturation ◽  
Uniaxial Tensile ◽  
Dry Density ◽  
Partially Saturated ◽  
Soil Shear Strength ◽  
Soil Tensile Strength

<p>Soil tensile strength plays an important role in the hydro-mechanical behaviour of earth structures and slopes interacting with the atmosphere. Shrinkage-induced cracking may be generated by drying/wetting cycles, with consequent faster water infiltration from the top of slopes and reduction of the safety factor. Vegetation roots were proven to increase soil shear strength, but less is known about their effects on soil tensile strength. For this purpose, new equipment has been designed and used to induce plant growth in compacted soil samples and to perform uniaxial tensile tests on the reinforced material. The equipment is composed of two cylindrical moulds linked by a soil bridge in which the tensile crack is induced due to geometrical restraints.</p><p>For this study, silty sand was chosen and compacted at a low dry density (ρ<sub>d</sub> = 1.60 Mg/m<sup>3</sup>) and at a water content w = 15%. After compaction, samples were gently poured with water up to a high degree of saturation (S<sub>r</sub> ≈ 0.95) and low suction (s ≈ 1 kPa). Then, six of them were seeded with Cynodon dactilon, adopting fixed seeding density and spacing. Plants were irrigated and let to grow for three months: during this period, suction was monitored by a tensiometer. Seven fallow specimens were prepared following the same procedure, for comparison purposes.</p><p>When ready, samples were dried in a temperature/relative humidity-controlled room and left in the darkness for three hours, to attain and equalise the desired value of initial suction. Finally, the tensile stress was induced on the soil by a displacement rate of 0.080 mm/min. For each test, suction was continuously monitored by a tensiometer while the water content was checked at the beginning and at the end. Moreover, the void ratio and the root volume and area ratio were assessed close to the crack generated, at the end of each test.</p><p>The hydraulic state affected the soil mechanical response upon uniaxial extension: an increase of strength and a more brittle behaviour were observed as suction was increasing. At the same suction, a higher strength was systematically observed in the vegetated soil. In fact, even at very low suction (i.e. s = 1 kPa), vegetation roots induced a considerable increase in soil tensile strength (i.e. 10 kPa). The soil hydraulic state also affected the root failure mechanism. In wet soil, the roots subjected to tension were stretched and pulled-out whereas in dry soil they experienced a more immediate breakage (i.e. in concomitance with the cracking of the surrounding soil). Some preliminary PIV (Particle Image Velocimetry) analyses showed differences among dry/wet and fallow/vegetated soils. Indeed, a more diffuse strain field was observed in vegetated samples, thanks to the redistribution of stresses induced by the roots.</p><p>Results were successfully interpreted by a well-established shear strength criterion for partially saturated soils, considering the degree of saturation, suction and soil microstructure. An increase of the soil shear strength was observed and correlated to the presence of roots and to their geometrical and mechanical features. Moreover, good consistency was detected with results coming from other equipment.</p><p> </p>

Development of a New Soil Tensile Strength Test Apparatus

2005 ◽  
Author(s):  
Surendra B. Tamrakar ◽  
Toshiyuki Mitachi ◽  
Yasuo Toyosawa ◽  
Kazuya Itoh
Keyword(s):  
Tensile Strength ◽  
Strength Test ◽  
Test Apparatus ◽  
Tensile Strength Test ◽  
Soil Tensile Strength

scholarly journals Measurement of Soil Tensile Strength and Factors Affecting its Measurements

2007 ◽  
Vol 47 (5) ◽  
pp. 911-918 ◽  
Author(s):  
Surendra bahadur Tamrakar ◽  
Toshiyuki Mitachi ◽  
Yasuo Toyosawa
Keyword(s):  
Tensile Strength ◽  
Factors Affecting ◽  
Soil Tensile Strength

Generation of microcracks in molded soils by rapid wetting

Soil Research ◽  
1989 ◽  
Vol 27 (1) ◽  
pp. 169 ◽  
Author(s):  
CD Grant ◽  
AR Dexter
Keyword(s):  
Water Management ◽  
Tensile Strength ◽  
Natural Regeneration ◽  
Soil Structure ◽  
Initial Water ◽  
Fracture Surfaces ◽  
Water Contents ◽  
Wetting Rate ◽  
Soil Tensile Strength

Tillage of compacted or of puddled and remoulded soils is a major agronomic problem internationally. The natural regeneration of microcracks (tilth mellowing) prior to the cultivation of such soils can reduce the energy needed to work them. Rapid wetting, under certain conditions, plays a major role in developing cracks in structurally damaged soils. This study reports the use of different initial water contents and wetting rates to examine the development of 'new' soil structure, described mechanically by tensile strength, and optically by measurements of the relief of fractured soil surfaces. New terminology is introduced to describe the rate of wetting needed to induce mellowing and to describe the rugosity of soil fracture surfaces. Rapid wetting was found to induce microcracking in soils, even with initial matric potentials as wet as -1.0 to -1.5 MPa. Implications for water management are briefly considered. Visual and analytical evidence from photographs and computer images indicates that internal microcracking is almost always detectable whenever the wetting rate is sufficiently high to reduce the soil tensile strength.

scholarly journals Tensile strength, friability and organic carbon in an oxisol under a crop-livestock system

2009 ◽  
Vol 66 (4) ◽  
pp. 499-505 ◽  
Author(s):  
Rachel Muylaert Locks Guimarães ◽  
Cássio Antonio Tormena ◽  
Sérgio José Alves ◽  
Jonez Fidalski ◽  
Éverton Blainski
Keyword(s):  
Tensile Strength ◽  
Organic Carbon ◽  
Soil Compaction ◽  
Soil Structure ◽  
Soil Depth ◽  
Limiting Factor ◽  
Surface Layers ◽  
Livestock Systems ◽  
Livestock System ◽  
Soil Tensile Strength

The crop-livestock system can promote soil compaction in surface layers, mainly due to animal trampling. However, plants and their root growth, in interaction with animal trampling, can decrease the deleterious changes in soil structure caused by this system. Up to the present time, the physical soil modifications in crop-livestock systems, including oat and ryegrass crops for winter animal forages are unknown. The objective of this study was to quantify and to relate tensile strength, friability and soil organic carbon in an Oxisol under a crop-livestock system. The study was conducted in Campo Mourão - Paraná, Brazil. Four forage heights were used for the winter forages: 7, 14, 21 and 28 cm. For each forage height, five soil blocks were randomly collected from each layer of 0 - 0.1, 0.1 - 0.2 and 0.2 - 0.3 m of depth. The increase in carbon content promotes an increase in soil tensile strength at the 0.1 - 0.2 m soil depth, this layer having the highest values for tensile strength. The forage height of 21 cm was found to be the best height for soil friability, and the soil was very friable at this height. Despite a decrease in friability in the upper layers of the soil, the crop-livestock system was not found to be a limiting factor for the subsequent cultivation of annual crops.

scholarly journals A Soil Tensile Strength Based Headcut Migration Model of Breach Side Slope

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2666
Author(s):  
Zhenzhen Liu ◽  
Tian Li ◽  
Yuxi Ding ◽  
Shuihua Jiang
Keyword(s):  
Tensile Strength ◽  
Present Model ◽  
Limit Equilibrium ◽  
Critical Length ◽  
Tensile Failure ◽  
Simple Method ◽  
Side Slope ◽  
Plane Normal ◽  
Geotechnical Characteristics ◽  
Soil Tensile Strength

The headcut migration describes the physical process of breach side slope retreat that governs the widening of the breach. Modeling the growth of a breach due to embankment failure is the first step in mapping the resulting inundation in a floodplain. As removal of soil from the toe of the headcut effectively removes physical support for the upper part, the headcut fails on the plane normal to the direction of tensile stress. This process is a typical mode of tensile failure. A numerical model of the headcut migration was established by integrating the effects of the soil tensile strength, soil permeability and embankment geotechnical characteristics. Thus, a simple analytical equation was finally obtained to predict the critical length of the headcut. Furthermore, the presented model was verified by using the limit equilibrium method (LEM) for three typical embankment scales (2, 4 and 6 m high). The comparisons between the present model and the LEM show good agreements. The present model could provide a simple method to predict the critical length of the headcut migration and easily be adopted to breach widening models.

Soil Tensile Strength by Centrifugation

1961 ◽  
Vol 25 (3) ◽  
pp. 176-180 ◽  
Author(s):  
J. A. Vomocil ◽  
L. J. Waldron ◽  
W. J. Chancellor
Keyword(s):  
Tensile Strength ◽  
Soil Tensile Strength
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