scholarly journals Triaxial Shear Behavior of a Gravelly Sand with Different Forms of Reinforcement

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jia-Quan Wang ◽  
Sen-Lei Hou ◽  
Jian-Feng Xue ◽  
Zhi-Nan Lin ◽  
Yi Tang
Keyword(s):  
Three Dimensional ◽  
Axial Loading ◽  
Reinforced Soil ◽  
Double Layers ◽  
Triaxial Tests ◽  
Hyperbolic Model ◽  
Strain Behavior ◽  
Apparent Cohesion ◽  
Confining Pressures ◽  
Strain Relationship

To study the effect of three-dimensional reinforcement arrangement on the behavior of a gravelly sand, triaxial tests were performed on specimens reinforced with geogrid sheet, geogrid cell, and one and two layers of geogrid sheet and geocell combination. Specimens with a diameter of 100 mm and a height of 200 mm are sheared under drained condition to monitor the variation of axial and volumetric strains with axial loading under different confining pressures. The results showed that the reinforcement schemes have different effects on soil strength improvement. The inclusion of double layers of geogrid sheet and geocell reinforcement could increase both the apparent cohesion and friction of the reinforced soil. The stress-strain relationship could be modelled with a modified hyperbolic model, which can capture the softening strain behavior of the specimens after peak strength.

Strength and Interaction of Soil Reinforced with Three-Dimensional Elements

2007 ◽  
Vol 340-341 ◽  
pp. 1285-1290
Author(s):  
M.X. Zhang ◽  
S.L. Zhang ◽  
J.M. Peng ◽  
A.A. Javadi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Shear Strength ◽  
Three Dimensional ◽  
Reinforced Soil ◽  
Experimental Results ◽  
Triaxial Tests ◽  
Retaining Structure ◽  
3D Elements ◽  
Element Method

For conventional reinforced soil, the reinforcements are put horizontally in the soil. A new concept of soil reinforced with three-dimensional elements was proposed. In 3D reinforced soil, besides conventional horizontal reinforcements, some vertical and 3D reinforcements can also be laid in the soil. The triaxial tests on sand reinforced with 3D reinforcement were carried out. From the experimental results, the differences of stress-strain relationship and shear strength between horizontal reinforced sand and 3D reinforced one were analyzed. The experimental results show that 3D reinforcement not only increases its cohesion, the angle of internal friction has been increased greatly, especially with 3D elements on both sides. Based on experimental results, a retaining structure reinforced with 3D reinforcements was analyzed by the finite element method. The stress distribution and interaction between 3D elements and soil were studied. The plastic zone and stability analysis of the retaining structure reinforced with 3D reinforcements were investigated by finite element method by shear strength reduction technique.

Anisotropic three-dimensional behavior of a normally consolidated clay

1993 ◽  
Vol 30 (5) ◽  
pp. 848-858 ◽  
Author(s):  
M.M. Kirkgard ◽  
P.V. Lade
Keyword(s):  
Pore Pressure ◽  
San Francisco ◽  
Triaxial Compression ◽  
Three Dimensional ◽  
Failure Surface ◽  
Triaxial Tests ◽  
Compression Tests ◽  
Principal Stresses ◽  
Stress Strain ◽  
Strain Behavior

An experimental study is presented of the influence of the intermediate principal stress on the stress–strain, pore-pressure, and strength characteristics of a normally consolidated, natural anisotropic clay, San Francisco Bay Mud, under undrained conditions. Consolidated undrained triaxial compression tests and triaxial tests with independent control of all three principal stresses on cubical specimens were performed. The stress–strain behavior and the pore-pressure characteristics as well as the effective stress failure surface can be described as being cross-anisotropic. Key words : anisotropic soils, clays, deformation, shear strength, triaxial tests.

An Analysis of the Strength of Anisotropic Granular Assemblies via Discrete Methods

2014 ◽  
Vol 553 ◽  
pp. 525-530
Author(s):  
Sergio Andres Galindo-Torres ◽  
Dorival Pedroso ◽  
David Williams ◽  
Hans Mühlhaus
Keyword(s):  
Shear Strength ◽  
Granular Media ◽  
Three Dimensional ◽  
Spherical Particles ◽  
Triaxial Tests ◽  
True Triaxial ◽  
Polyhedral Particles ◽  
Granular Assemblies ◽  
Mean Pressure ◽  
Confining Pressures

This paper presents a study on the macroscopic strength characteristics of granular assemblies with three-dimensional complex-shaped particles. Different assemblies are considered, with both isotropic and anisotropic particle geometries. The study is conducted using the Discrete Element Method (DEM), with so-called sphero-polyhedral particles, and simulations of mechanical true triaxial tests for a range of Lode angles and confining pressures. The observed mathematical failure envelopes are investigated in the Haigh-Westergaard stress space, as well as on the deviatoric-mean pressure plane. It is verified that the DEM with non-spherical particles produces results that are qualitatively similar to experimental data and previous numerical results obtained with spherical elements. The simulations reproduce quite well the shear strength of assemblies of granular media, such as higher strength during compression than during extension. In contrast, by introducing anisotropy at the particle level, the shear strength parameters are greatly affected, and an isotropic failure criterion is no longer valid. It is observed that the strength of the anisotropic assembly depends on the direction of loading, as observed for real soils.

Triaxial Test and Numerical Analysis on the Fiber Reinforced Laterite Clay

2013 ◽  
Vol 275-277 ◽  
pp. 1219-1224 ◽  
Author(s):  
Jin Li Zhang ◽  
Man Yuan ◽  
Zheng Guo Jiang ◽  
Qing Yang
Keyword(s):  
Three Dimensional ◽  
Calculation Model ◽  
Secondary Development ◽  
Triaxial Tests ◽  
Fiber Reinforced ◽  
Stress Strain ◽  
Nonlinear Fitting ◽  
Strain Relationship ◽  
Straight Lines ◽  
Relationship Of

Triaxial compressive tests were performed on laterite clay(LC) reinforced with different fiber contents and lengths. It was observed that the curves of stress-strain have a segmented characteristic at the critical strain. The stress-strain curves of fiber reinforced laterite clay(FRLC) were expressed by the combination of hyperbola and straight lines. The parameters of stress-strain curves were obtained by linear and nonlinear fitting method with experimental results. A three-dimensional calculation model of triaxial tests was developed on the basis of ABAQUS software. To express the stress-strain relationship of hyperbola-straight lines, user’s subroutine was established through secondary development. Based on the test conditions, a large number of calculations were conducted. There is a good agreement between the results of numerical calculations and tests. It shows that the stress-strain relationship of FRLC can be described by the hyperbola-straight line combination model.

Experiment Research on Dynamic Characteristics of Ground Fissure Belt Loess in Xi 'an Area

2013 ◽  
Vol 387 ◽  
pp. 138-146 ◽  
Author(s):  
Ya Hong Deng ◽  
Huan Dong Mu ◽  
Jian Bing Peng ◽  
Yan Qiu Leng ◽  
Zhen Feng Sun ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Damping Ratio ◽  
Triaxial Tests ◽  
Dynamic Shear Modulus ◽  
Site Condition ◽  
Ground Fissure ◽  
Ground Fissures ◽  
Confining Pressures ◽  
Dynamical Parameters ◽  
Strain Relationship

The Fenwei Basin can be the most developed area of ground fissures as well as the associated geo-hazard in China and even in the world .Considering the ground fissure disasters influence on site condition, especially on the dynamic characteristics and dynamic response of site soil, in this paper, under the condition of constant pressure consolidation, consolidated undrained dynamic triaxial tests are carried on Xi'an area ground fissures belt loess with different confining pressures and dynamical parameters are obtained. Based on the experimental results, the dynamic stress-strain relationship, the change laws of dynamic shear modulus and damping ratio are analyzed. The equivalent visco-elastic constitutive model is also established.

The Experimental Study on the Performance of the Reinforced Red Mudstone Using Triaxial Tests

2012 ◽  
Vol 446-449 ◽  
pp. 1445-1449
Author(s):  
Shuai Zhuo ◽  
Ning Wang ◽  
Ping Lu ◽  
Yong Yao
Keyword(s):  
Ambient Pressure ◽  
Triaxial Compression ◽  
Reinforced Soil ◽  
Triaxial Tests ◽  
Steel Material ◽  
Reinforcement Material ◽  
Strain Relationship ◽  
Material Sample ◽  
Better Than ◽  
Compaction Degree

via the red mudstone proceed of the unconsolidated and non-drained triaxial compression test, the research in different degree of compaction reinforcement material under the influence of red mudstone strength. To the different reinforcement layers, different ambient pressure test, analyses not reinforcement material layer number of decorate the more the better, decorate three layer of steel material is better than the four layers of reinforcement decorate material sample. The analysis in different degree of compaction element soil and reinforced soil under test result, the reinforcement material that can obviously increase the strength of the soil, and in different degree of compaction soil under the different strength, and with the degree of compaction to improve the stress-strain relationship curves by strain softening type to strain change sclerosis type. Analysis of the С value of the red mudstone compaction degree with the increased and rise, but theφ rise and reduced.

Stiffness degradation and shear strength of silty sands

2004 ◽  
Vol 41 (5) ◽  
pp. 831-843 ◽  
Author(s):  
Junhwan Lee ◽  
Rodrigo Salgado ◽  
J Antonio H Carraro
Keyword(s):  
Shear Strength ◽  
Nonlinear Behavior ◽  
Triaxial Tests ◽  
Hyperbolic Model ◽  
Soil Behavior ◽  
Cone Penetration ◽  
Stress Strain ◽  
Early Loading ◽  
Realistic Representation ◽  
Strain Relationship

Soils behave nonlinearly from very early loading stages. When granular soils contain a certain amount of fines, the degree of nonlinearity also changes, as stiffness and strength characteristics vary with fines content. Hyperbolic stress–strain models and variations of these models are often used for description of the nonlinear behavior. A modified hyperbolic stress–strain relationship is used in this paper for representing the degradation of the elastic modulus of silty sands. The model is based on two modulus degradation parameters that determine the magnitude and rate of modulus degradation as a function of stress level. Realistic representation of soil behavior using this nonlinear relationship requires estimation of the degradation parameters as a function of silt content and relative density DR. A series of triaxial test results on sands containing different amounts of nonplastic silt were analyzed with this purpose. Relationships between the degradation parameters and cone penetration test (CPT) cone resistance qc are also proposed.Key words: hyperbolic model, silty sands, triaxial tests, modulus degradation, stress–strain response, shear strength, Gmax.

scholarly journals Stress–strain relationship model of glulam bamboo under axial loading

2020 ◽  
Vol 29 ◽  
pp. 2633366X2095872
Author(s):  
Yang Wei ◽  
Mengqian Zhou ◽  
Kunpeng Zhao ◽  
Kang Zhao ◽  
Guofen Li
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Failure Modes ◽  
Axial Loading ◽  
Tensile Failure ◽  
Stress Strain ◽  
Laminated Bamboo ◽  
Bamboo Scrimber ◽  
Strain Relationship ◽  
Strain Model

Glulam bamboo has been preliminarily explored for use as a structural building material, and its stress–strain model under axial loading has a fundamental role in the analysis of bamboo components. To study the tension and compression behaviour of glulam bamboo, the bamboo scrimber and laminated bamboo as two kinds of typical glulam bamboo materials were tested under axial loading. Their mechanical behaviour and failure modes were investigated. The results showed that the bamboo scrimber and laminated bamboo have similar failure modes. For tensile failure, bamboo fibres were ruptured with sawtooth failure surfaces shown as brittle failure; for compression failure, the two modes of compression are buckling and compression shear failure. The stress–strain relationship curves of the bamboo scrimber and laminated bamboo are also similar. The tensile stress–strain curves showed a linear relationship, and the compressive stress–strain curves can be divided into three stages: elastic, elastoplastic and post-yield. Based on the test results, the stress–strain model was proposed for glulam bamboo, in which a linear equation was used to describe the tensile stress–strain relationship and the Richard–Abbott model was employed to model the compressive stress–strain relationship. A comparison with the experimental results shows that the predicted results are in good agreement with the experimental curves.

Comparison of Field Behavior with Results from Numerical Analysis of a Geosynthetic Reinforced Soil Integrated Bridge System Subjected to Thermal Effects

2020 ◽  
Vol 2674 (1) ◽  
pp. 294-306
Author(s):  
Arshia Taeb ◽  
Phillip S.K. Ooi
Keyword(s):  
Pressure Fluctuations ◽  
Axial Loading ◽  
Reinforced Soil ◽  
Element Analysis ◽  
Vertical Pressure ◽  
Geosynthetic Reinforced Soil ◽  
End Wall ◽  
Cyclic Straining ◽  
Toe Pressure ◽  
Bridge System

When subjected to ambient daily temperature fluctuations, a 109.5 ft-long geosynthetic reinforced soil integrated bridge system (GRS-IBS) was observed to undergo cyclic straining of the superstructure. The upper and lower reaches of the superstructure experienced the highest and lowest strain fluctuation, respectively. These non-uniform strains impose not only axial loading of the superstructure but also bending. Pure axial loading in a horizontal superstructure will cause the footings to slide. However, bending in the superstructure will cause the footings to rotate thereby inducing cyclic fluctuations of the vertical pressure beneath the footing and also lateral pressure behind the end walls. Measured vertical footing pressure closest to the stream experienced the greatest daily pressure fluctuation (≈ 2,500–3,000 psf), while that nearest the end wall experienced the least. The toe pressure fluctuations seem rather large. That these large vertical pressure fluctuations are observed in a tropical climate like Hawaii when no other GRS-IBS in temperate regions has reported the same (or perhaps higher fluctuation) is indeed surprising. The larger these pressures are, the greater the likelihood of inducing cyclic-induced deformations of the GRS abutment. A finite element analysis of the same GRS-IBS was performed by applying an equivalent temperature and gradient to the superstructure over the coldest and hottest periods of a day to see if the field measured values of pressures are reasonable and verifiable, which indeed they were. This methodology is novel in the sense that the effects of axial load and bending of the superstructure are simulated using measured strains rather than measured temperatures.

Mechanical behaviour of powders using a medium pressure flexible boundary cubical triaxial tester

2003 ◽  
Vol 217 (3) ◽  
pp. 233-241 ◽  
Author(s):  
F Li ◽  
V M Puri
Keyword(s):  
Shear Modulus ◽  
Mechanical Behaviour ◽  
Triaxial Compression ◽  
Three Dimensional ◽  
Volumetric Strain ◽  
Confining Pressure ◽  
Alumina Powder ◽  
Medium Pressure ◽  
Mean Pressure ◽  
Confining Pressures

A medium pressure (<21 MPa) flexible boundary cubical triaxial tester was designed to measure the true three-dimensional response of powders. In this study, compression behaviour and strength of a microcrystalline cellulose powder (Avicel® PH102), a spray-dried alumina powder (A16SG), and a fluid-bed-granulated silicon nitride based powder (KY3500) were measured. To characterize the mechanical behaviour, three types of triaxial stress paths, that is, the hydrostatic triaxial compression (HTC), the conventional triaxial compression (CTC), and the constant mean pressure triaxial compression (CMPTC) tests were performed. The HTC test measured the volumetric response of the test powders under isostatic pressure from 0 to 13.79MPa, during which the three powders underwent a maximum volumetric strain of 40.8 per cent for Avicel® PH102, 30.5 per cent for A16SG, and 33.0 per cent for KY3500. The bulk modulus values increased 6.4-fold from 57 to 367MPa for Avicel® PH102, 3.7-fold from 174 to 637 MPa for A16SG, and 8.1-fold from 74 to 597MPa for KY3500, when the isotropic stress increased from 0.69 to 13.79 MPa. The CTC and CMPTC tests measured the shear response of the three powders. From 0.035 to 3.45MPa confining pressure, the shear modulus increased 28.7-fold from 1.6 to 45.9MPa for Avicel® PH102, 35-fold from 1.7 to 60.5MPa for A16SG, and 28.5-fold from 1.5 to 42.8MPa for KY3500. In addition, the failure stresses of the three powders increased from 0.129 to 4.41 MPa for Avicel® PH102, 0.082 to 3.62 MPa for A16SG, and 0.090 to 4.66MPa for KY3500, respectively, when consolidation pressure increased from 0.035 to 3.45MPa. In addition, the shear modulus and failure stress values determined from the CTC test at 2.07, 2.76, and 3.45MPa confining pressures are consistently greater than those from the CMPTC test at the same constant mean pressures. This observation demonstrates the influence of stress paths on material properties. The CTT is a useful tool for characterizing the three-dimensional response of powders and powder mixtures.

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