Study on Stress-Strain Behavior of Cohesive Soil Mixing with Gravel by Triaxial Test

2012 ◽  
Vol 446-449 ◽  
pp. 1573-1576
Author(s):  
Yuan Long Wang ◽  
Jun Gao Zhu ◽  
Jian Fang Zhou

The mechanical behaviors of a cohesive soil mixing with gravel were investigated in consolidated-drained triaxial tests. Three soils with different percentages of gravel mixed with the cohesive soil, i.e. 50%, 75% and 87.5%, were tested, and the inference of gravel percentage to the stress-strain behavior is investigated. The results indicate that the shear strength of the soil increases with the increase of gravel percentage. Compared to peak strength of GP50, that of GP75 and GP87.5 increases by 14.4%~32.8% and 20.9%~40.5%. The initial and secant Young’s modulus of the soil increases significantly when the gravel percentage is greater than 75%.

2012 ◽  
Vol 446-449 ◽  
pp. 1573-1576
Author(s):  
Yuan Long Wang ◽  
Jun Gao Zhu ◽  
Jian Fang Zhou

2011 ◽  
Vol 250-253 ◽  
pp. 1366-1370 ◽  
Author(s):  
Kai Fu Liu ◽  
Xiang Ru Yang ◽  
Xin Yu Xie ◽  
Chang Fu Wu ◽  
Yong Hai Liu

Laboratory triaxial tests of the soil reinforced with roots of Manilagrass were carried out in order to understand the stress-strain relationship. The change of shear strength indexes of the soil reinforced with roots of Manilagrass was investigated with the quantity of grassroots planted in the soil specimens. The results of laboratory triaxial tests show that the strength and capacity for resisting the deformation of soil reinforced with roots are better than those of unreinforced soil. And under the certain number of grassroots layers, the strength and capacity for resisting the deformation of soil reinforced with roots increase firstly and then reduce with the increasing of Manilagrass roots quantity. In other words, there is an optimal quantity of Manilagrass roots affecting the strength and capacity for resisting the deformation of soil reinforced with roots. The research results are important for understanding the mechanism and use of vegetation protection for slope.


2005 ◽  
Vol 42 (2) ◽  
pp. 459-474 ◽  
Author(s):  
Marika Santagata ◽  
John T Germaine

The paper presents the results of an experimental investigation of sampling disturbance in cohesive soils through single-element triaxial tests on resedimented Boston blue clay (RBBC). The first part of the paper discusses the effect of the overconsolidation ratio (OCR) (1–8) of the soil on postdisturbance compression and undrained shear behavior. The results demonstrate that sensitivity to disturbance decreases markedly with OCR. It is also found that for the medium-sensitivity soil tested, the estimate of the preconsolidation pressure is not significantly affected by OCR. The second part of the paper discusses laboratory reconsolidation procedures. For OCR1 RBBC, the recompression method is not effective in recovering the stress–strain behavior of the soil and, for greater disturbance, provides an increasingly unsafe estimate of the strength. For OCR4, provided the reconsolidation path reproduces the path that occurred in the field, this procedure succeeds in recovering the intact stress–strain–strength behavior of the soil. SHANSEP reconsolidation was investigated for normally consolidated RBBC only. For modest levels of disturbance, this is an effective means of evaluating both the stress–strain and the strength behavior of the soil. For greater levels of disturbance, the stress–strain behavior is not fully recovered, but the method continues to provide conservative estimates of the undrained strength.Key words: sampling disturbance, clays, overconsolidation ratio, undrained strength, recompression, SHANSEP.


2020 ◽  
Vol 975 ◽  
pp. 203-207
Author(s):  
Shih Tsung Hsu ◽  
Wen Chi Hu ◽  
Yu Heng Lin ◽  
Zhuo Ling

Constitutive models for soils are usually adopted in numerical method to analyze the behavior of geotechnical structures. This study performs a series of consolidated-undrained triaxial tests to establish the stress-strain curve of clay. A constitutive model that considers continuous strain hardening-softening is proposed based on the results of triaxial tests. Triaxial test results reveal that undrained shear strength linearly increases with an increase in consolidated pressure , the normalized undrained shear strength is about 0.52 not only for this study but also for the other two cases around Taipei Basin. Due to undrained condition, an associated flow rule between plastic strain increment and stress tensor is adopted. As accumulative plastic strain or/and consolidated pressure change, the mobilized undrained shear strength also changes. All parameters needed for the proposed model can be expressed as a function of undrained shear strength Su, The mobilized undrained shear strength for the proposed model during strain hardening-softening can be in term of accumulative plastic strain. This model can calculate the stress-strain curves of clayed soils accurately.


2006 ◽  
Vol 29 (2) ◽  
pp. 12686 ◽  
Author(s):  
L David Suits ◽  
TC Sheahan ◽  
P Ratnaweera ◽  
JN Meegoda

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Syahmizzi Ifwat Bin Azharnim ◽  
Mohd Jamaludin Md. Noor

Effective stress and shear strength interaction which the stress – strain curves and mobilised shear strength envelope explained the actual volume change behaviour of the soils. The interaction that useful in prediction of stress – strain curves and unique relationship between Effective Mobilised Minimum Friction Angle and Axial Strain is important to predict the settlement at any effective stresses include the effective stress that not conducted in laboratory test. Consolidated drained triaxial test is conducted for saturated Banting CLAY and the volume change behaviour of Banting CLAY is presented from the concept of effective stress and shear strength interaction with the establishment of unique relationship between effective mobilised minimum friction angle with respect to axial strain and prediction of stress – strain curves for the saturated Banting CLAY.


2021 ◽  
Vol 337 ◽  
pp. 01018
Author(s):  
Christian Barahona ◽  
Luis Sandi ◽  
Juan Carlos Rojas ◽  
Di Emidio Gemmina ◽  
Adam Bezuijen ◽  
...  

This paper presents the results of an experimental study on the effects of testing rate on stress-strain behavior and volumetric changes of soil. A series of suction-controlled triaxial tests has been performed on reconstituted specimens of a silty sand (SM), at different stress-rates and strain-rates, respectively. The stress-strain paths were applied by using a modified version of a Bishop and Wesley device (USPv2), capable of applying independently pore-water and air pressure at both ends of the soil sample. During the isotropic compression stages loading rates of 2 and 32 kPa/h have been applied under constant suction values of 15 and 45 kPa. The drained deviator stages were conducted at the same suction levels under strain rates of 0.25 and 2.50 %/h. Results are presented in terms of applied loading rates as a function of the specimens specific volume, preconsolidation pressure, soil compressibility and deviatoric stress against strain rate. A comparison of results was made to a former study, under similar testing conditions of suction and loading rates at University of Napoli Federico II. The effect of loading rate on the soil behavior seems to have an insignificant effect on the specific volume variations, for the imposed values during the testing campaign.


2011 ◽  
Vol 243-249 ◽  
pp. 2176-2182
Author(s):  
Bin Xu ◽  
De Gao Zou ◽  
Tao Gong ◽  
Xian Jing Kong ◽  
Jing Bi

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.


1982 ◽  
Vol 19 (4) ◽  
pp. 413-420
Author(s):  
J. Lafleur ◽  
G. Lefebvre ◽  
M. Marcotte ◽  
V. Silvestri

This paper describes the sampling procedure and the results of large diameter (150 mm) CID triaxial tests made on samples recovered from the weathered clay crust of the Champlain sea deposits.A visual inspection of the fissures at the depth of sampling (3 m) revealed two types of discontinuities: (a) sub-vertical joints containing black organic matter, spaced approximately every 10 cm, and (b) closed microfissures, randomly distributed in spacing and direction. In order to recover unremoulded samples of this material and avoid a difficult retrimming in the laboratory, a double core barrel 150 mm in diameter (the same as that of the triaxial cell base) was used. Eight compression tests under low confining stresses were made; they showed that the post-peak strength parameters were substantially higher than those back-calculated from a landslide involving the same weathered crust. Examination of the shape of the failure planes and of the stress–strain curves led to the conclusion that, in spite of the large sample size, the propagation of the fractures was controlled by the intact clay matrix rather than by the fissures. Since this was not believed to reproduce the actual field behaviour, a complementary test programme was undertaken, which indicated that the strength parameters were better evaluated from CID tests performed in the normally consolidated range. Keywords: fissured clays, weathering, landslides, triaxial test, shear strength parameters, sampling, back-analysis.


1993 ◽  
Vol 30 (5) ◽  
pp. 848-858 ◽  
Author(s):  
M.M. Kirkgard ◽  
P.V. Lade

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.


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