An Artificial Material for Simulating Champlain Clays

1973 ◽  
Vol 10 (3) ◽  
pp. 489-503 ◽  
Author(s):  
F. A. Tavenas ◽  
M. Roy ◽  
P. La Rochelle
Keyword(s):  
Mechanical Properties ◽  
Effective Stress ◽  
Sampling Technique ◽  
Model Material ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Failure Envelope ◽  
Synthetic Material ◽  
Strain Behavior

As part of an investigation on the behavior of Champlain clays, full scale penetrometer and vane tests had to be performed in the laboratory to observe the behavior of the soil during such tests. Since it was impossible to obtain samples of the necessary size, it was decided to develop a synthetic material which would model the mechanical properties of the Champlain clays.Such a model material has been defined. It consists of a mixture of kaolinite, bentonite, cement, and water. It is first shown to have a stress–strain behavior identical to that of the clay in unconfined compression tests, provided it is aged for 16 days. It is also shown to simulate very well all other mechanical properties of the Champlain clays, and more particularly the peculiar shape of the failure envelope in effective stress as well as the preconsolidation pressure.This material has been used successfully for laboratory penetrometer tests. It can also be used for the installation of instruments in situ or for the analysis of any testing or sampling technique.

Experiment on Mechanical Properties and Seepage Capability of Deep Tight Sandstone Under True-Triaxial Stresses Environment

2021 ◽  
Author(s):  
Jiaying Li ◽  
Chunyan Qi ◽  
Ye Gu ◽  
Yu Ye ◽  
Jie Zhao
Keyword(s):  
Mechanical Properties ◽  
In Situ Stress ◽  
Stress Sensitivity ◽  
Stress Conditions ◽  
Tight Sandstone ◽  
Gas Reservoir ◽  
True Triaxial ◽  
Strain Behavior ◽  
Triaxial Stresses

Abstract The characteristics of seepage capability and rock strain during reservoir depletion are important for reservoir recovery, which would significantly influence production strategy optimization. The Cretaceous deep natural gas reservoirs in Keshen Gasfield in Tarim Basin are mainly buried over 5000 m, featuring with ultra-low permeability, developed natural fractures and complex in-situ stress states. However, there is no comprehensive study on the variation of mechanical properties and seepage capability of this gas reservoir under in-situ stress conditions and most studies on stress-sensitivity are conducted under conventional triaxial or uniaxial stress conditions, which cannot truly represent in-situ stress environment. In this work, Cretaceous tight sandstone in Keshen Gasfield was tested under true-triaxial stresses conditions by an advanced geophysical imaging true-triaxial testing system to study the stress-sensitivity and anisotropy of rock stress-strain behavior, porosity and permeability. Four groups of sandstone samples are prepared as the size of 80mm×80mm×80mm, three of which are artificially fractured with different angle (0°,15°，30°) to simulate hydraulic fracturing. The test results corresponding to different samples are compared to further reveal the influence of the fracture angle on rock mechanical properties and seepage capability. The samples are in elastic strain during reservoir depletion, showing an apparent correlation with fracture angles. The porosity decreases linearly with stress loading, where the decrease rate of effective porosity of fracture samples is significantly higher than that of intact samples. The permeabilities decrease exponentially and show significant anisotropy in different principal stress directions, especially in σH direction. The mechanical properties and seepage capability of deep tight sandstone are successfully tested under true-triaxial stresses conditions in this work, which reveals the stress-sensitivity of anisotropic permeability, porosity and stress-strain behavior during gas production. The testing results proposed in this paper provides an innovative method to analyse rock mechanical and petrophysical properties and has profound significance on exploration and development of tight gas reservoir.

Stabilization of clayey subgrade with waste pumice for road infrastructure

2015 ◽  
Vol 22 (5) ◽  
Author(s):  
Ömür Çimen ◽  
Mehmet Saltan ◽  
S. Nilay Keskin
Keyword(s):  
Mechanical Properties ◽  
Road Construction ◽  
High Plasticity ◽  
Test Results ◽  
Index Properties ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Swelling Potential ◽  
Project Costs ◽  
High Plasticity Clay

AbstractHigh-plasticity clayey subgrade, which is unsuitable for road construction, may sometimes occur along highway routes. In such cases, engineers need to change the route of a highway project, resulting in an increase in road length and project costs. In this study, waste pumice was examined for stabilization of high-plasticity clayey subgrade, which is inappropriate for road construction. For this purpose, the physical and index properties of clay and pumice were determined. Then, the pumice was mixed with high plasticity clay at different ratios by weight. By performing standard Proctor compaction tests on the mixtures, the effects of adding pumice on compaction were also studied. Unconfined compression tests and California bearing ratio (CBR) tests were performed on all pumice-clay mixtures, and the test results and the CBR ratios were compared for each sample, respectively. The results showed that pumice stabilization improved the mechanical properties and reduced the swelling potential of high plasticity clayey subgrade.

Influence of Experimental Protocols on the Mechanical Properties of the Intervertebral Disc in Unconfined Compression

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
Maximilien Recuerda ◽  
Simon-Pierre Coté ◽  
Isabelle Villemure ◽  
Delphine Périé
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Nucleus Pulposus ◽  
Annulus Fibrosus ◽  
Young's Modulus ◽  
Viscoelastic Model ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Experimental Conditions ◽  
Experimental Protocols

The lack of standardization in experimental protocols for unconfined compression tests of intervertebral discs (IVD) tissues is a major issue in the quantification of their mechanical properties. Our hypothesis is that the experimental protocols influence the mechanical properties of both annulus fibrosus and nucleus pulposus. IVD extracted from bovine tails were tested in unconfined compression stress-relaxation experiments according to six different protocols, where for each protocol, the initial swelling of the samples and the applied preload were different. The Young’s modulus was calculated from a viscoelastic model, and the permeability from a linear biphasic poroviscoelastic model. Important differences were observed in the prediction of the mechanical properties of the IVD according to the initial experimental conditions, in agreement with our hypothesis. The protocol including an initial swelling, a 5% strain preload, and a 5% strain ramp is the most relevant protocol to test the annulus fibrosus in unconfined compression, and provides a permeability of 5.0 ± 4.2e−14m4/N·s and a Young’s modulus of 7.6 ± 4.7 kPa. The protocol with semi confined swelling and a 5% strain ramp is the most relevant protocol for the nucleus pulposus and provides a permeability of 10.7 ± 3.1 e−14m4/N·s and a Young’s modulus of 6.0 ± 2.5 kPa.

Fabrication of Aluminum/Aluminum Nitride Composites by Reactive Mechanical Alloying

2007 ◽  
Vol 534-536 ◽  
pp. 181-184
Author(s):  
Seung Hoon Yu ◽  
Kwang Seon Shin
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Elevated Temperatures ◽  
Hot Extrusion ◽  
Extrusion Process ◽  
Processing Technique ◽  
Compression Tests ◽  
Composite Powders ◽  
Al Matrix Composites

Various reactions and the in-situ formation of new phases can occur during the mechanical alloying process. In the present study, Al powders were strengthened by AlN, using the in-situ processing technique during mechanical alloying. Differential thermal analysis and X-ray diffraction studies were carried out in order to examine the formation behavior of AlN. It was found that the precursors of AlN were formed in the Al powders and transformed to AlN at temperatures above 600oC. The hot extrusion process was utilized to consolidate the composite powders. The composite powders were canned in an Al can and then extruded at elevated temperatures. The microstructure of the extrusions was examined by SEM and TEM. In order to investigate the mechanical properties of the extrusions, compression tests and hardness measurements were carried out. It was found that the mechanical properties and the thermal stability of the Al/AlN composites were significantly greater than those of conventional Al matrix composites.

Mechanical properties and dislocation dynamics of GaP

1989 ◽  
Vol 4 (2) ◽  
pp. 355-360 ◽  
Author(s):  
Ichiro Yonenaga ◽  
Koji Sumino
Keyword(s):  
Mechanical Properties ◽  
Dislocation Dynamics ◽  
Dynamic State ◽  
Strain Rates ◽  
Compression Tests ◽  
Stress Strain ◽  
Temperature Range ◽  
Strain Behavior ◽  
Defect Complexes ◽  
Impurity Defect

Mechanical properties of GaP crystals are investigated in the temperature range 600–900 °C by means of compression tests. Stress-strain characteristics of a GaP crystal in the temperature range 600–800 °C are very similar to those of a GaAs crystal in the temperature range 450–600 °C. The dynamic state of dislocations during deformation is determined by means of the strain-rate cycling technique. The deformation of GaP is found to be controlled by the dislocation processes the same as those in other kinds of semiconductors such as Si, Ge, and GaAs. The velocity v of dislocations that control deformation is deduced to be v = v0 τ exp(–2.2 eV/kT) as a function of the stress τ and the temperature T, where v0 is a constant and k the Boltzmann constant. The Portevin-LeChatelier effect is observed in the stress-strain behavior in the deformation at high temperatures and under low strain rates, which may be attributed to the locking of dislocations by impurities or impurity-defect complexes.

The Elastic Properties of a Dense Glacial Till Deposit

1965 ◽  
Vol 2 (2) ◽  
pp. 116-128 ◽  
Author(s):  
Earle J Klohn
Keyword(s):  
Elastic Properties ◽  
Modulus Of Elasticity ◽  
Elastic Solid ◽  
Strength Properties ◽  
Glacial Till ◽  
Triaxial Tests ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Sample Disturbance

Dense, heavily preconsolidated glacial till is a relatively incompressible soil that occurs throughout most of Canada. When loaded, it undergoes very small settlement, most of which is elastic. For the average structure, these elastic compressions are too small to be of concern and are usually ignored. However, for some structures they can be critical and their magnitude must be estimated prior to construction. To make the necessary analyses requires knowledge of the elastic properties of the in situ glacial till.This paper presents the results of field and laboratory tests that were made on a dense glacial till deposit to determine its modulus of elasticity, in connection with the design and construction of a 100 ft. high combined earth and concrete dam. In the field, in situ loading tests were made against the walls of a 50 ft. deep test shaft. The modulus of elasticity was computed, using elastic equations applicable to the case of a rigid circular plate pressed against a semi-infinite elastic solid. Moreover, during construction of the project, measurements were made of the elastic rebounds and settlements that occurred under known conditions of unloading and loading. Steinbrenner’s approximate solution for computing settlement due to loads acting on the surface of an elastic layer was then used to compute the apparent modulus of elasticity. In the laboratory, unconfined compression tests and repetitive triaxial tests were made on undisturbed samples. The modulus of elasticity was estimated from the stress-strain relationships obtained.The data presented in the paper indicate that the apparent, in situ modulus of elasticity of the glacial till deposit is very high, being in the order of 150,000 lb./sq. in. Reasonable agreement exists between modulus of elasticity values computed from the in situ plate bearing tests and those computed from observed rebounds and settlements. However, modulus of elasticity values computed from unconfined compression and repetitive triaxial tests in the laboratory are apparently too small, being only a fraction of those values obtained by the field procedures. Sample disturbance is thought to be a major factor affecting laboratory test results.Grain size characteristics, density, natural water content, and strength properties of the glacial till deposit are presented in the paper. These data provide a comprehensive description of the material and permit comparison with glacial till deposits encountered at other areas.

scholarly journals Influence of curing temperature and stress conditions on mechanical properties of cementing paste backfill

2016 ◽  
Vol 53 (1) ◽  
pp. 148-161 ◽  
Author(s):  
Megan L. Walske ◽  
Heather McWilliam ◽  
James Doherty ◽  
Andy Fourie
Keyword(s):  
Mechanical Properties ◽  
Effective Stress ◽  
Elevated Temperatures ◽  
Small Strain ◽  
Curing Temperature ◽  
Temperature Conditions ◽  
In Situ Conditions ◽  
Paste Backfill ◽  
Temperature Controlled

Cemented paste backfill (CPB) has been observed to achieve greater cemented strength when cured in situ compared with equivalent mixes cured and tested in a laboratory environment. This is in part due to the development of effective stress and generation of elevated temperatures by exothermic cement hydration reactions occurring during curing in a typical underground stope environment. This differs from curing in typical laboratory environments, where little or no effective stresses are generated and curing occurs under constant-temperature conditions. This paper outlines the development, calibration, and testing of a temperature-controlled hydration cell that provides closer representation of in situ conditions by controlling the rate and final amount of specimen temperature increase, in addition to curing under effective stress. The temperature-controlled hydration cell was used to examine the effect of curing under combined effective stress and temperature conditions on the development of small-strain stiffness over a 7 day curing period and the unconfined compressive strength at the end of this period. Curing with both elevated temperature and effective stress was found to significantly increase the mechanical properties of CPB compared with curing at elevated effective stress or ambient temperatures alone.

Mechanical properties of the porcine growth plate and its three zones from unconfined compression tests

2009 ◽  
Vol 42 (4) ◽  
pp. 510-516 ◽  
Author(s):  
Kim Sergerie ◽  
Marc-Olivier Lacoursière ◽  
Martin Lévesque ◽  
Isabelle Villemure
Keyword(s):  
Mechanical Properties ◽  
Growth Plate ◽  
Compression Tests ◽  
Unconfined Compression

scholarly journals Experimental study on the effect of chitosan biopolymer on sandy soil stabilization

2020 ◽  
Vol 195 ◽  
pp. 06007
Author(s):  
Nader Shariatmadari ◽  
Mohammad Reza ◽  
Amiri Tasuji ◽  
Pooria Ghadir ◽  
A. Akbar Javadi
Keyword(s):  
Mechanical Properties ◽  
Sandy Soil ◽  
Contaminated Soils ◽  
Soil Stabilization ◽  
Soil Improvement ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Curing Conditions ◽  
Removal Of Heavy Metals ◽  
Chitosan Biopolymer

Due to the environmental impacts of conventional soil stabilization materials, such as cement, ongoing efforts have been carried out by different researchers to find alternative economical materials for substitution. Biopolymers are environmentally friendly materials that are widely used in different geoenvironmental applications such as removal of heavy metals from contaminated soils, reduction of soil hydraulic conductivity, erosion control, and soil improvement. In this research the feasibility of using chitosan biopolymer for sandy soil stabilization has been studied. The effects of biopolymer content, curing time, and curing conditions have investigated using unconfined compression tests. The results indicated that incorporation of chitosan has the potential to increase the interparticle cohesion between the particles and considerable improvement of sandy soil mechanical properties. After initial strengthening of the soil, some strength reduction over time was observed due to the degradation characteristics of the chitosan. With regards to the curing condition, better performances at dry condition compare to the wet and saturated environment were achieved. In addition to soil mechanical properties, the pore plugging effect of chitosan biopolymer on highly permeable sandy soil has been studied in this study.

Sign in / Sign up

Export Citation Format

Share Document