Study on Engineering Characteristics of Coarse-Grained Soil Based on Large-Scale Triaxial Test

2014 ◽  
Vol 936 ◽  
pp. 1387-1392
Author(s):  
Fu Yong Chu
Keyword(s):  
Triaxial Test ◽  
Large Scale ◽  
Confining Pressure ◽  
Peak Strength ◽  
Coarse Grained ◽  
Engineering Characteristics ◽  
Increase With Increase ◽  
Initial Modulus ◽  
Relationship Of ◽  
Coarse Grained Soil

Using large-scale shearing device, isotropiclly consolidated-drained triaxial test under different confining pressures are performed for overburden material of ShuangJiangKou earthdam which relative density is 0.9. The engineering characteristics of coarse-grained soil such as strength and deformation is studied. The results show the peak strength of coarse-grained soil under isotropically increase with the confining pressure and there is a relationship of linear between the peak strength of coarse-grained soil and initial modulus. The volume strain value of isotropically consolidated-drained triaxial shear test increase with increase of confining pressure, and the dilatancy decrease increase with increase of confining pressure. The secant modulusEs1and the tangent modulusEt1obtained by the tests both increase with increase with increase of confining pressure, and the values ofEs1/EiandEt1/Eiare all smaller than one. The failure poisson ratioνifobtained by the tests both decrease with increase with increase of confining pressure, and there is a relationship of power function between νif and .

Study on Particle Breakage of Coarse-Grained Soil Based on Large-Scale Triaxial Test

2014 ◽  
Vol 937 ◽  
pp. 585-589
Author(s):  
Fu Yong Chu
Keyword(s):  
Power Function ◽  
Triaxial Test ◽  
Large Scale ◽  
Confining Pressure ◽  
Particle Breakage ◽  
Plastic Work ◽  
Coarse Grained ◽  
Earth Dam ◽  
Relationship Of ◽  
Coarse Grained Soil

Using large-scale shearing device, isotropiclly consolidated-drained triaxial test under different confining pressures are performed for overburden material of ShuangJiangKou earth dam which relative density is 0.8. The relationship between particle breakage of coarse-grained soil and input plastic work under loading and between particle breakage and confining pressure and between particle breakage and strength of coarse-grained soil. The results show that the particle breakage of coarse-grained soil and the input plastic work under loading is closely related. The particle breakage of coarse-grained soil increase with the input plastic work and there is a relationship of power function between Bg andWp. the increase of confining pressure will lead to the increase of particle breakage of coarse-grained soil, and there is a relationship of power function between Bg and. the increase of particle breakage of coarse-grained soil will lead to the decrease of strength of coarse-grained soil, and a relationship of linear between Bg andφ.

Influence Factor on Dilatancy of Coarse-Grained Soil Based on Large-Scale Triaxial Test

2014 ◽  
Vol 919-921 ◽  
pp. 687-692 ◽  
Author(s):  
Fu Yong Chu
Keyword(s):  
Relative Density ◽  
Triaxial Test ◽  
Large Scale ◽  
Confining Pressure ◽  
Coarse Grained ◽  
Earth Dam ◽  
Triaxial Shear Test ◽  
Overburden Material ◽  
Confining Pressures ◽  
Coarse Grained Soil

Abstract：Using large-scale shearing device, K0 consolidated-drained triaxial test and isotropiclly consolidated-drained triaxial test under different confining pressures are performed for overburden material of ShuangJiangKou earth dam which relative density is 0.9. And meanwhile, isotropically consolidated-drained triaxial test under different confining pressures are also performed for overburden material of ShuangJiangKou earth dam which relative density is 0.8. The difference of strength and deformation between under under K0-consolidation condition and isotropic consolidation condition and between under different relative density, and the influence of confining pressure, relative density and consolidation condition on the dilatancy of coarse-grained are analyzed. The results show that the strength of K0 consolidated-drained triaxial shear test is slight greater than that obtained by isotropically consolidated-drained test. The strength of coarse-grained soil increases with increase of relative density.The volume strain value of isotropically consolidated-drained triaxial shear test is bigger than that of K00 consolidated-drained test, and the volume strain value decreases with the decreases of relative density. The dilatancy of coarse-grained soil decreases with the increase of confining pressure, and increases with the increase of static lateral pressure coefficient.

scholarly journals Macro-Micromechanical Properties of Sandy Pebble Soil of Different Coarse-Grained Content

2018 ◽  
Vol 22 (1) ◽  
pp. 65-71
Author(s):  
Junfu Lu ◽  
Di Li ◽  
Xiaoqiang Xue ◽  
Shenlin Ling
Keyword(s):  
Internal Friction ◽  
Triaxial Test ◽  
Large Scale ◽  
Strain Curve ◽  
Friction Angle ◽  
Confining Pressure ◽  
Discrete Element ◽  
Internal Friction Angle ◽  
Coarse Grained ◽  
Research Results

Sandy pebble stratum is a typical discrete particle unstable stratum, mainly consisting of sand and pebble. However, the effect of coarse-grained content on the stability of stratum is not clear. This paper defined the sandy pebble soil of different coarse-grained content in Chengdu City, Sichuan Province, China as the research object. Research on macro-mesomechanical properties of sandy pebble soil of different coarse-grained content was carried out using the method combining the indoor large-scale triaxial test of coarse-grained soil with the discrete element numerical triaxial test. The research results showed that the stress-strain curve of sandy pebble soil exhibited strain softening with the increase of coarse-grained content; when the confining pressure was the same, the stress peak increased and the strain when the peak was reached decreased gradually with the increase of coarse-grained content. It revealed the functional relationship between coarse-grained content and mechanical indexes of sandy pebble soil such as internal friction angle and cohesion. The internal friction angle and cohesion of sandy pebble soil linearly increased with the rise of coarse-grained material; it proposed the particle discrete element micro parameters of sandy pebble soil of different coarse-grained content, including contact modulus, friction coefficient, particle stiffness ratio, contact bond strength. The research results provided the theoretical support for the new design and construction of sandy pebble stratum project. 

scholarly journals New Structure for Strengthening Soil Embankments

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Fang Xu ◽  
Wuming Leng ◽  
Rusong Nie ◽  
Qishu Zhang ◽  
Qi Yang
Keyword(s):  
Shear Modulus ◽  
Large Scale ◽  
Dynamic Stress ◽  
Confining Pressure ◽  
Coarse Grained ◽  
Triaxial Tests ◽  
Additional Stress ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Critical Dynamic

A new prestressed reinforcement device (PRD) consisting of two lateral pressure plates (LPPs) and a reinforcement bar is developed to strengthen soil embankments by improving the soil confining pressure and providing lateral constraint on embankment slopes. The reinforcement effects of PRDs were demonstrated by investigating the beneficial effects of increasing confining pressure on the soil behavior via the performance of a series of large-scale static and cyclic triaxial tests on a coarse-grained embankment soil. The results show that PRDs can effectively improve the soil shear strength, bearing capacity, ability to resist elastic and plastic deformation, critical dynamic stress, and dynamic shear modulus, and empirical methods were also developed to determine the critical dynamic stress and initial dynamic shear modulus of the embankment soil. Moreover, 3D finite element analyses (FEAs) with an LPP width of 1.2 m were performed to analyze the additional stress field in a prestressed heavy-haul railway embankment. The FEAs showed that the additional stress at a given external distance from the border of an LPP first increased to a maximum value and then gradually decreased with increasing depth; the additional stress was transferred to the zones where the subgrade tends to have higher stresses with peak stress diffusion angles of 34° (slope direction) and 27° (longitudinal direction); and a continuous effective reinforcement zone with a minimum additional stress coefficient of approximately 0.2 was likely to form at the diffusion surface of the train loads, provided that the net spacing of the LPPs was 0.7 m. The reinforcement zone above the diffusion surface of the train loads can act as a protective layer for the zones that tend to have higher stresses. Finally, the advantages and application prospects of PRDs are discussed in detail. The newly developed PRDs may provide a cost-effective alternative for strengthening soil embankments.

Dynamic Stress-Strain Relationship of Saturated Clay by Dynamic Triaxial Test

2011 ◽  
Vol 250-253 ◽  
pp. 3183-3186
Author(s):  
Jian Yi Yuan
Keyword(s):  
Triaxial Test ◽  
Dynamic Stress ◽  
Soft Clay ◽  
Confining Pressure ◽  
Dynamic Shear ◽  
Stress Strain ◽  
Dynamic Triaxial Test ◽  
Wide Range ◽  
Strain Relationship ◽  
Relationship Of

Subgrade diseases are exposed more and more serious with raising speed of existing railway in wide range. Fro the complexity of dynamic stress-strain relationship of soil, dynamic triaxial test was used to analyze .the dynamic mechanics behavior under cyclic train load for saturated soft clay in Yangtze Delta region. Compaction coefficient, confining pressure, dynamic shear strsss ratio, inputing stimulus and loading frequence were taken into account in test. The results show that the dynamic stress-strain curves of soil specimen are provided with prominent hysteretic characteristics and area surrounded by hysteretic curves gradually augment and slope of hysteretic curve decreases with the increase of dynamic shear train amplitude. The strong correlation exists between dynamical stress and strain.

Microstructural Evolution of Synthetic Forsterite Aggregates Deformed to High Strain

2004 ◽  
Vol 467-470 ◽  
pp. 579-584 ◽  
Author(s):  
A. Kellermann Slotemaker ◽  
J.H.P. de Bresser ◽  
C.J. Spiers ◽  
M.R. Drury
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Grain Growth ◽  
Microstructural Evolution ◽  
Large Scale ◽  
High Strain ◽  
Confining Pressure ◽  
Size Reduction ◽  
Coarse Grained ◽  
Fine Grained

Microstructures provide the crucial link between solid state flow of rock materials in the laboratory and large-scale tectonic processes in nature. In this context, microstructural evolution of olivine aggregates is of particular importance, since this material controls the flow of the Earth’s upper mantle and affects the dynamics of the outer Earth. From previous work it has become apparent that if olivine rocks are plastically deformed to high strain, substantial weakening may occur before steady state mechanical behaviour is approached. This weakening appears directly related to progressive modification of the grain size distribution through competing effects of dynamic recrystallization and syn-deformational grain growth. However, most of our understanding of these processes in olivine comes from tests on coarse-grained materials that show grain size reduction through dynamic recrystallization. In the present study we focused on fine-grained (~1 µm) olivine aggregates (i.e., forsterite/Mg2SiO4), containing ~0.5 wt% water and 10 vol% enstatite (MgSiO3), Samples were axially compressed to varying strains up to a maximum of ~45%, at 600 MPa confining pressure and a temperature of 950°C. Microstructures were characterized by analyzing full grain size distributions and textures using SEM/EBSD. We observed syndeformational grain growth rather than grain size reduction, and relate this to strain hardening seen in the stress-strain curves.

Study on Grain Breakage in Triaxial Test of Rockfill Material

2011 ◽  
Vol 261-263 ◽  
pp. 1598-1602
Author(s):  
Jia Jun Pan ◽  
Xi Bao Rao ◽  
Yong Zhen Zuo
Keyword(s):  
Sample Preparation ◽  
Triaxial Test ◽  
Large Scale ◽  
Confining Pressure ◽  
Linear Relations ◽  
Rockfill Material ◽  
Rockfill Materials ◽  
Grain Breakage

Large-scale triaxial test has been conducted on various rockfill materials in an attempt to study the degrees of grain breakage. The result has shown that, the grain breakage occurred during sample preparation can not be neglected, and to maintain the initial gradation design prior to consolidation, the gradation design shall be adjusted downwards to a certain extent accordingly before sample preparation. The breakage of large-sized grains mainly occurs on the surface, and the grain breakage and confining pressure has shown linear relations after triaxial test.

Study on Influence of Geotechnical Grille Characteristic on Mechanics Properties of Reinforced Sand-Gravel

2011 ◽  
Vol 243-249 ◽  
pp. 2176-2182
Author(s):  
Bin Xu ◽  
De Gao Zou ◽  
Tao Gong ◽  
Xian Jing Kong ◽  
Jing Bi
Keyword(s):  
Shear Strength ◽  
Residual Strength ◽  
Large Scale ◽  
Great Influence ◽  
Volumetric Strain ◽  
Peak Strength ◽  
Brittleness Index ◽  
Triaxial Tests ◽  
Reinforced Sand ◽  
Initial Modulus

A series of large scale consolidated drained shear triaxial tests were performed on geotechnical grille reinforced sand-gravel specimens, the aim was to study influence of elongation and strength characteristic of geotechnical grille on initial modulus, peak strength, residual strength, brittleness index, volumetric strain and shear strength of reinforced sand-gravel. The results show that: the elongation of geotechnical grille used in the sand-gravel specimens has great influence on residual strength, brittleness index and cohesion of reinforced sand-gravel, but the initial modulus, peak strength and volumetric strain are affected slightly.

Study on the Deformation and Strength Characteristics of Geotechnical Grille Reinforced Sand-Gravel under Low Confining Pressure

2011 ◽  
Vol 250-253 ◽  
pp. 2632-2639
Author(s):  
Bin Xu ◽  
De Gao Zou ◽  
Jing Bi ◽  
Xian Jing Kong ◽  
Tao Gong
Keyword(s):  
Residual Strength ◽  
Large Scale ◽  
Volumetric Strain ◽  
Friction Angle ◽  
Confining Pressure ◽  
Peak Strength ◽  
Strength Characteristics ◽  
Triaxial Tests ◽  
Reinforced Sand ◽  
Deformation And Strength Characteristics

A series of large scale consolidated drained shear triaxial tests were performed on reinforced and unreinforced sand-gravel specimens, the peak strength and residual strength characteristics of reinforced and unreinforced sand-gravel specimens were compared. The results show that: the peak strength, the residual strength and cohesion of reinforced sand-gravel are higher than unreinforced specimens, and is related to the characteristics of geotechnical grille used in this study. However, adding geotechnical grille has less effect on maximum volumetric strain and internal friction angle of sand-gravel.

scholarly journals A Constitutive Model of Sandy Gravel Soil under Large-Sized Loading/Unloading Triaxial Tests

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Pengfei Zhang ◽  
Han Liu ◽  
Zhentu Feng ◽  
Chaofeng Jia ◽  
Rui Zhou
Keyword(s):  
Constitutive Model ◽  
Large Scale ◽  
Confining Pressure ◽  
Peak Strength ◽  
Triaxial Tests ◽  
Model Parameters ◽  
Sandy Gravel ◽  
Cumulative Volume ◽  
Gravel Soil ◽  
Confining Pressures

Based on large-scale triaxial tests of sandy gravel materials, the strength and deformation characteristics under loading/unloading conditions are analyzed. At the same time, the applicability of the hyperbolic constitutive model to sandy gravel is studied using experimental data. The results indicate that sandy gravel under low confining pressures (0.2 and 0.4 MPa) shows a weak softening trend; the higher the confining pressure, the more obvious the hardening tendency (0.6 and 0.8 MPa) and the greater the peak strength. During unloading tests, strain softening occurs, and the peak strength increases with increasing confining pressure. During loading tests, dilatancy appears when the confining pressure is low (0.2 MPa). With increasing confining pressure (0.4, 0.6, and 0.8 MPa), the dilatancy trend gradually weakens, and the cumulative volume tric strain increases, which reflects the relevance of the stress paths. Through research, it is found that the hyperbolic constitutive model has good applicability to sandy gravel soils, and the corresponding model parameters are obtained.

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