The effects of dissipated energy on mechanical behavior of carbonate sands using monotonic triaxial tests

This paper focuses on the mechanical behavior and damage evolution of Huashan granite subjected to cyclic loading. Four levels of confining pressure (0, 15, 25, and 35 MPa) were applied during cyclic axial loading by using a Rock Test System (MTS815) along with an acoustic emission (AE) monitoring device. Experimental results indicate that the number of AE activities is higher under cyclic triaxial loading compared to that under cyclic uniaxial loading. The measured stress-strain curves of both uniaxial and triaxial tests under cyclic loading are concave-up, but the degree of concavity is mild for the latter. As the cycle number rises, elastic modulus of the granite sample under different confining pressures increases. The slope of the peak strength versus confining pressure plot for the cyclic loading is larger than that for the monotonic loading. Besides, it is found that the dissipated energy increases with the increase of cyclic stress, but it hardly increases in proportion with the confining pressure. The damage parameters defined in terms of the plastic strain can be extended for the whole cyclic loading process, and they agree well with the energy-based damage parameters.

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Influence of drainage and root biomass on soil mechanical behavior in triaxial tests

Acta Geotechnica ◽

10.1007/s11440-021-01380-w ◽

2021 ◽

Author(s):

Mehtab Alam ◽

Yuan-Jun Jiang ◽

Muhammad Umar ◽

Li-jun Su ◽

Mahfuzur Rahman ◽

...

Keyword(s):

Mechanical Behavior ◽

Root Biomass ◽

Triaxial Tests

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Cyclic Triaxial Tests with Continuous Measurement of Dissipated Energy

Geotechnical Testing Journal ◽

10.1520/gtj10822j ◽

1983 ◽

Vol 6 (1) ◽

pp. 35 ◽

Cited By ~ 24

Author(s):

ET Selig ◽

KJ Simcock ◽

RO Davis ◽

JB Berrill ◽

G Mullenger

Keyword(s):

Continuous Measurement ◽

Triaxial Tests ◽

Dissipated Energy ◽

Cyclic Triaxial ◽

Cyclic Triaxial Tests

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Use of Nanosilica and Cement in Improving the Mechanical Behavior of Disintegrated Carbonaceous Mudstone

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.18483 ◽

2020 ◽

Vol 20 (8) ◽

pp. 4807-4814 ◽

Cited By ~ 3

Author(s):

Ling Zeng ◽

Xiaofei Yao ◽

Qian-Feng Gao ◽

Hanbing Bian ◽

Dianhua Fan

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Mechanical Behavior ◽

Pozzolanic Reaction ◽

Deviatoric Stress ◽

Triaxial Tests ◽

X Ray Diffraction ◽

X Ray ◽

Angle Of Internal Friction ◽

Scanning Electron

This study aims to examine the mechanical behavior of disintegrated carbonaceous mudstone modified with nanosilica and cement (DCMNC). Many DCMNC specimens with various nanosilica contents were prepared. The X-ray diffraction (XRD) analyses and scanning electron microscopy (SEM) observations were performed on some of the specimens. Afterwards, triaxial tests were carried out on the remaining specimens to determine the mechanical behavior of DCMNC. The results showed that the cohesion exhibited a positive correlation with nanosilica content while the angle of internal friction presented a negative correlation with nanosilica content. The peak deviatoric stress, residual deviatoric stress and brittle modulus of DCMNC showed an increase followed by a decrease as nanosilica content varied from 0 to 8%, and all of them reached corresponding maximums at a nanosilica content of 2%. Thus, 2% was considered to be the optimum nanosilica content. The modification mechanism of DCMNC could be explained by the pozzolanic reaction related to nanosilica and the filling effect of nanosilica.

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

Advances in Materials Science and Engineering ◽

10.1155/2021/8893840 ◽

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.

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Microstructural Characteristics of Interfacial Zone in Asphalt Mixture Considering the Influence of Aggregates Properties

Materials ◽

10.3390/ma13112558 ◽

2020 ◽

Vol 13 (11) ◽

pp. 2558 ◽

Cited By ~ 1

Author(s):

Jing Hu ◽

Qibo Huang ◽

Ning Lou ◽

Sang Luo

Keyword(s):

Mechanical Behavior ◽

Mechanical Characteristics ◽

Asphalt Mixture ◽

Dissipated Energy ◽

Interfacial Zone ◽

Microstructural Characteristics ◽

Viscoelastic Parameters ◽

Significant Difference ◽

Microstructural Morphology ◽

Asphalt Mortar

The interfacial zone between aggregate particles and asphalt mortar presents a significant effect on the strength of an asphalt mixture. In this paper, basalt, limestone, and diabase were selected, and the influence of these aggregates on the mechanical characteristics and microstructures of the interfacial zone was investigated. Nanoindentation was employed to measure the change law of mechanical behavior in the region of the interfacial zone, and corresponding viscoelastic parameters were deduced; microstructural morphology was observed by scanning electron microscopy, and the effect of the mineralogical components on the interfacial zone was analyzed as well. Results show that the mechanical behavior of the interfacial transition zone is complicated. The modulus and hardness of asphalt mortar decrease with the increases in the aggregate surface distance, and then keep stable after the distance is greater than 40 μm. Both the relaxation time and dissipated energy ratio of the interfacial zone affected by the different aggregate types show a similar change law. These states indicate that aggregate types have little influence on the stress dissipation of asphalt mortar. However, creep compliances that quantify the ability of the deformation resistance show a significant difference; microstructure morphologies of the interfacial zone are affected by aggregates obviously, and micro pores present a different distribution and state in the interfacial zone.

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Triaxial Test and Mechanical Analysis of Rock-Soil Aggregate Sampled from Natural Sliding Mass

Advances in Materials Science and Engineering ◽

10.1155/2015/238095 ◽

2015 ◽

Vol 2015 ◽

pp. 1-14 ◽

Cited By ~ 7

Author(s):

Shuling Huang ◽

Xiuli Ding ◽

Yuting Zhang ◽

Wei Cheng

Keyword(s):

Mechanical Behavior ◽

Large Scale ◽

Mechanical Response ◽

Strain Curve ◽

Friction Angle ◽

Mechanical Analysis ◽

Soil Aggregate ◽

Hydropower Plant ◽

Triaxial Tests ◽

Confining Pressures

Rock-soil aggregate, as a specific geomaterial, exhibits complicated mechanical behavior. The rock-soil aggregate sampled from the deep layer of sliding mass at Jinpingzi area of Wudongde hydropower plant on Yangtze River is investigated to understand its mechanical behavior. Large-scale laboratory triaxial tests are conducted considering different gradations, stone contents and confining pressures. The results show that variation of stone content and gradation considerably affects the mechanical characteristics of rock-soil aggregate. Further, the influences of stone content, and gradation variation on stress-strain curve, Mohr-Coulomb criterion based shear strength parameters, Duncan-Chang model based deformation parameters, and internal friction angle are analyzed. A modified Rowe’s stress-dilatancy equation describing the mechanical response of rock-soil aggregate is then suggested.

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Managing Sanding Risk in Sandstone Reservoir Through a New Constitutive Model

10.2118/204666-ms ◽

2021 ◽

Author(s):

Surej Kumar Subbiah ◽

Ariffin Samsuri ◽

Assef Mohamad-Hussein ◽

Mohd Zaidi Jaafar ◽

Yingru Chen ◽

...

Keyword(s):

Constitutive Model ◽

Mechanical Behavior ◽

Failure Criteria ◽

Reservoir Rock ◽

Triaxial Tests ◽

Sand Production ◽

Gas Field ◽

Sandstone Rock ◽

Sandstone Reservoir ◽

Rock Mechanical Behavior

Abstract Sandstone reservoir failure during hydrocarbon production can cause negative impact on the oil/gas field development economics. Loss of integrity and hydrocarbon leakage due to downhole or surface erosion can decrease the risk of operational safety. Therefore, a proper understanding of the best formulation to manage and find the balance between productivity and sand risk is very important. Making decisions for the best and most economical completion design needs a full and proper sanding risk analysis driven by geomechanics modeling. The accuracy of modeling the reservoir rock mechanical behavior and the failure analysis depends on the selection of the constitutive model (failure criteria) specially to understand the failure and post failure mechanisms. Thus, an appropriate constitutive model/criterion is required as most of the current model/criteria are not developed for a weak rock material honoring the non-linearity and post failure (softening) process. Therefore, a new and novel elasto-plastic constitutive model for sandstone rock has been investigated and developed. The effort started with a sequence of triaxial tests at different confining pressures on core samples. Different types of rock have been tested during the developing and validation of the constitutive model. Comparison with other existing failure criteria was also performed. As the results, the newly developed constitutive model is better honoring the full spectrum of elasto-plastic rock mechanical behavior (softening and post-failure) which is important for oil and gas applications, specifically for sand production and drilling i.e. failure stabilization due to stress relief. The formulation and process are demonstrated with a case study for an old gas field, where a few gas wells have been shut-in due to severe sand production. The sand production predictive models have been validated with downhole pressure. The wells have been side-tracked and recompleted using the new sand failure prediction, using the new formulation resulted in restoring sand-free production at former rates. The novelty of this study would be in finding the right formula to best design the predictive model and to avoid any sand production when using the newly developed constitutive model.

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Effect of load shape on relationship between dissipated energy and residual excess pore pressure generation in cyclic triaxial tests

Canadian Geotechnical Journal ◽

10.1139/cgj-2012-0379 ◽

2013 ◽

Vol 50 (11) ◽

pp. 1118-1128 ◽

Cited By ~ 25

Author(s):

Carmine Polito ◽

Russell A. Green ◽

Erin Dillon ◽

Changbum Sohn

Keyword(s):

Pore Pressure ◽

Water Pressure ◽

Laboratory Data ◽

Excess Pore Pressure ◽

Triaxial Tests ◽

Dissipated Energy ◽

Generation Model ◽

Cyclic Triaxial ◽

Cyclic Triaxial Tests ◽

Load Shape

The energy dissipated in soil during cyclic loading can be used to predict the change in the pore-water pressure developed in the soil. To examine whether the energy required to cause liquefaction is dependent on or independent of the load shape applied, a series of 28 cyclic triaxial tests were performed using five different load shapes having a range of cyclic stress ratios. The five load shapes were applied to identically prepared specimens of clean sand and the dissipated energy – pore pressure generation characteristics examined. It was found that that the dissipated energy to cause initial liquefaction was normally distributed and independent of the load shape, although it is seemingly somewhat dependent on duration of loading. A corollary to this finding is that laboratory data from specimens tested using sinusoidal loadings can be used to calibrate the Green, Mitchell, and Polito (GMP) energy-based pore pressure generation model for use in predicting in situ pore pressures in soils subjected to nonsinusoidal loadings (e.g., earthquake loadings). Given the relative simplicity of the GMP model, these findings make the model an attractive alternative to implement in effective stress dynamic response codes.

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Mechanical Behavior, Energy Release, and Crack Distribution Characteristics of Water-Saturated Phyllite under Triaxial Cyclic Loading

Advances in Civil Engineering ◽

10.1155/2021/3681439 ◽

2021 ◽

Vol 2021 ◽

pp. 1-16

Author(s):

Yang Zhou ◽

Shengrui Su ◽

Peng Li

Keyword(s):

Cyclic Loading ◽

Mechanical Behavior ◽

Energy Release ◽

Damage Variable ◽

Dissipated Energy ◽

Distribution Characteristics ◽

Mechanical Behaviors ◽

Dynamic Mechanical ◽

Crack Distribution ◽

Water Saturated

Many geological engineering hazards are closely related to the dynamic mechanical behaviors of rock materials. However, the dynamic mechanical behaviors of phyllite are less studied. In this study, we have carried out a series of triaxial cyclic tests on dry and water-saturated phyllite by employing the MTS 815 servohydraulic testing system and AE testing equipment to reveal the mechanical behavior, energy release, and crack distribution characteristics of phyllite. Results show that phyllite is a water-sensitive rock. Water and cyclic loading substantially affect the compressive strength, crack damage stress, deformation parameters, dilatancy, energy release, and crack distribution characteristics of phyllite. Furthermore, based on the dissipated energy, a new damage variable for phyllite is established. The critical damage variable for phyllite is approximately 0.80; this variable can be used as an index to predict the failure of phyllite. The water saturation effect of phyllite is very obvious; that is, it results in the weakness of mechanical properties of phyllite and changes the AE energy release and crack distribution characteristics of phyllite. This research can provide guidance for engineering construction and disaster prevention and control.

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