scholarly journals Large-Scale Triaxial Tests on Dilatancy Characteristics of Lean Cemented Sand and Gravel

2021 ◽  
Vol 9 ◽  
Author(s):  
Hang Yu ◽  
Xue-mei Shen ◽  
Yu-chen Ye ◽  
Jie Yang ◽  
Chen-hui Zhu
Keyword(s):  
Plastic Strain ◽  
Strain Increment ◽  
Triaxial Tests ◽  
Volume Strain ◽  
Triaxial Loading ◽  
Cemented Sand ◽  
Plastic Strain Increment ◽  
Loading And Unloading ◽  
Sand And Gravel ◽  
Increment Ratio

The dilatancy equation, which describes the plastic strain increment ratio and its dependence on the stress state, is an important component of the elastoplastic constitutive model of geotechnical materials. In order to reveal their differences of the dilatancy value determined by the total volume strain increment ratio and the real value of lean cemented sand and gravel (LCSG) materials, in this study, a series of triaxial compression tests, equiaxial loading and unloading tests, and triaxial loading and unloading tests are conducted under different cement contents and confining pressures. The results reveal that hysteretic loops appear in the stress–strain curves of equiaxial loading and unloading tests, and triaxial loading and unloading tests and that the elastic strain is an important component of the total strain. The hysteretic loop size increases with an increase in the stress level or consolidation stress, whereas the shape remains unchanged. Furthermore, with an increase in the cement content, the dilatancy value determined by the total volume strain increment ratio becomes smaller than that determined by the plastic strain increment ratio, and the influence of the elastic deformation cannot be ignored. Thus, in practical engineering scenarios, especially in the calculation of LCSG dam structures, the dilatancy equation of LCSG materials should be expressed by the plastic strain increment ratio, rather than the total volume strain increment rati.

Experimental Study on Mechanical Characteristics of CSG Materials

2011 ◽  
Vol 243-249 ◽  
pp. 2059-2064
Author(s):  
De Gao Zou ◽  
Dong Qing Li ◽  
Bin Xu ◽  
Xian Jing Kong
Keyword(s):  
Mechanical Characteristics ◽  
Shear Failure ◽  
Triaxial Tests ◽  
Cemented Sand ◽  
Optimum Water Content ◽  
Strain Relationship ◽  
Mode Stress ◽  
New Type ◽  
Sand And Gravel ◽  
Optimum Water

Cemented sand and gravel (CSG) is a new type of dam materials. It not only can reduce the waste of resources and environmental pollution, but has the merits of both gravel and concrete. In this study, Cemented sand and gravel specimens with three cement ratios were compacted at optimum water content and cured for 14 days. Based on the consolidated drained shear triaxial tests, the mechanical properties of different proportion of CSG are studied on shear failure mode, stress-strain relationship, shear strength. Research results showed that, with the increasing of the content of cement, the peak and residual strength of CSG were improved, but the failure strains were decreased. In addition, CSG material behaves distinctly softening.

scholarly journals Experimental Study on Mechanical Behavior of Lean Cemented Sand and Gravel Material in Unloading and Reloading Paths

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jie Yang ◽  
An-yu Yang ◽  
Yan-gong Shan ◽  
Miao-miao Yang ◽  
Jin-lei Zhao ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Hysteresis Loop ◽  
Triaxial Test ◽  
Volumetric Strain ◽  
Rate Of Change ◽  
Coarse Grained ◽  
Triaxial Tests ◽  
Water Drainage ◽  
Cemented Sand ◽  
Sand And Gravel

Lean cemented sand and gravel (LCSG) materials are subjected to unloading-loading when an LCSG dam is opened for water drainage and then refilled or a roadbed base is subjected to repeated wheel loads. To investigate the behavior of the LCSG materials under loading-unloading, previous studies utilized the complete loading triaxial test. In contrast, in this study, the consolidated drained triaxial tests in the unloading and reloading paths for materials with cementing agent contents of 60 and 100 kg/m3 under different confining pressures, for which each curve generates three loading-unloading cycles, were applied to investigate the unloading and reloading mechanical behavior. Experimental results indicated that the unloading and reloading behavior of the LCSG materials produced stress-strain curves exhibiting a crescent-shaped hysteresis loop, which differs from that exhibited by coarse-grained soil. Although the shape of the crescent-like hysteresis loop was preserved as stress levels increasing, it gradually expanded. Compared with that of the typical triaxial test, the cohesive force and the increasing internal friction angle increased. Further, as the confining pressure increased, the crescent-like hysteresis loops tapered, shear strength increased linearly, and the modulus of resilience increased nonlinearly; the latter’s rate of change, however, decreased. The change in volumetric strain was small during unloading as the stress level changed.

Non-Coaxial Plasticity Constitutive Modeling of Sands

2013 ◽  
Vol 684 ◽  
pp. 150-153 ◽  
Author(s):  
Ping Hu ◽  
Mao Song Huang ◽  
Deng Gao Wu
Keyword(s):  
Plastic Strain ◽  
Constitutive Model ◽  
Principal Stress ◽  
Three Dimensional ◽  
Constitutive Models ◽  
Strain Increment ◽  
Stress Axis ◽  
Shear Tests ◽  
Plastic Strain Increment ◽  
Principal Axes

Classical coaxial plasticity constitutive models implicate an inevitable limitation that directions for principal stress and that for principal plastic strain increment are always coaxial. They are not capable of simulating non-coaxial phenomena during the rotation of principal stress axis. In this paper, a three-dimensional, non-coaxial plasticity constitutive model for sands with a modification of Lade angle dependent shape function is introduced to describe the non-coaxial behavior under principal axes rotation. A series of numerical simulations of hollow cylindrical torsional shear tests are performed. The results show that the proposed constitutive model can predict the variations of principal plastic strain increment directions with principal stress directions reasonably.

Yielding and Flow of Sand in Triaxial Compression: Parts II and III

1967 ◽  
Vol 4 (4) ◽  
pp. 376-397 ◽  
Author(s):  
H B Poorooshasb ◽  
I Holubec ◽  
A N Sherbourne
Keyword(s):  
Plastic Strain ◽  
Experimental Evidence ◽  
Potential Function ◽  
Triaxial Compression ◽  
Strain Increment ◽  
Flow Rule ◽  
Plastic Strain Increment ◽  
Yield Loci

In Part I,* based on experimental evidence, the existence of a potential function to define the gradient of the plastic strain increment vector was proved. The study is continued in Part II by defining the term yielding, a discussion of the form of the yield loci and a presentation of the “flow rule.”

Subsequent Yield Surfaces for Annealed Mild Steel Under Servo-Controlled Strain and Load Histories: Aging, Normality, Convexity, Corners, Bauschinger and Cross Effects

1975 ◽  
Vol 97 (1) ◽  
pp. 25-32 ◽  
Author(s):  
M. J. Michno ◽  
W. N. Findley
Keyword(s):  
Plastic Strain ◽  
Axial Load ◽  
Kinematic Hardening ◽  
Axial Stress ◽  
Axial Strain ◽  
Small Strain ◽  
Strain Increment ◽  
Limit Curve ◽  
Yield Curves ◽  
Plastic Strain Increment

Initial-yield results on SAE 1017 steel are presented for: four different specimens under combined axial load and twisting moment for servo controlled loading; and six different specimens under various combinations of servo controlled axial strain and shear strain. Subsequent yield curves determined by small strain offset multiple probes on a given specimen are presented covering all four quadrants of axial stress-shear stress space. The resulting families of subsequent yield curves allows conclusions to be drawn concerning the effects of plastic strain and strain aging. All curves were found to be convex and normality of the plastic strain increment vector was obeyed. The response to plastic straining allowed discussion of corner formation, translation, rotation, Bauschinger and cross effects of subsequent yield curves and formation of a limit curve. A comparison is made between the experiments and the Prager kinematic hardening model and the Ziegler modification.

Subsequent Yield Surfaces for Annealed Mild Steel Under Dead-Weight Loading: Aging, Normality, Convexity, Corners, Bauschinger, and Cross Effects

1974 ◽  
Vol 96 (1) ◽  
pp. 56-64 ◽  
Author(s):  
M. J. Michno ◽  
W. N. Findley
Keyword(s):  
Plastic Strain ◽  
Strain Aging ◽  
Strain Increment ◽  
Plastic Range ◽  
Dead Weight ◽  
Yield Curves ◽  
Plastic Strain Increment ◽  
Multiple Probe ◽  
Sharp Corners ◽  
Tubular Specimens

After initial yielding of one to five percent small-offset multiple-probe yield curves were determined under combined axial-torsion loading for six tubular specimens. Subsequent yield curves were obtained following either strain aging or loading into the plastic range. Aging and plastic straining usually resulted in smooth, convex yield curves. Occasionally well-rounded blunt corners were formed under combined tension and torsion. Subsequent curves underwent translation and changes in shape. Plastic strain increment vectors from zigzag loadings supported well-rounded blunt (not sharp) corners. Normality of plastic strain increment vectors was observed.

Plastic strain increment in low-carbon steel

2020 ◽  
Author(s):  
Y. V. Li ◽  
A. M. Nikonova ◽  
S. A. Barannikova
Keyword(s):  
Carbon Steel ◽  
Plastic Strain ◽  
Low Carbon Steel ◽  
Strain Increment ◽  
Low Carbon ◽  
Plastic Strain Increment
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