scholarly journals Experimental Study on Anisotropic Strength and Deformation Behavior of a Coal Measure Shale under Room Dried and Water Saturated Conditions

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Jingyi Cheng ◽  
Zhijun Wan ◽  
Yidong Zhang ◽  
Wenfeng Li ◽  
Syd S. Peng ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Young’S Modulus ◽  
Deformation Behavior ◽  
Young's Modulus ◽  
Triaxial Compression ◽  
Coal Measure ◽  
Anisotropic Strength ◽  
Strength And Deformation ◽  
Water Saturated

This paper presents an experimental investigation of anisotropic strength and deformation behavior of coal measure shale. The effect of two factors (i.e., anisotropy and water content) on shale strength and deformation behavior was studied. A series of uniaxial and triaxial compression tests were conducted on both room dried and water saturated samples for different lamination angles. The test results indicate that (1) the compressive strength, cohesion, internal friction angle, tangent Young’s modulus, and axial strain corresponding to the peak and residual strengths of room dried specimens exhibit anisotropic behavior that strongly depends on the orientation angle(β); (2) in comparison to the room dried samples, the compressive strength and Young’s modulus as well as the anisotropy are all reduced for water saturated specimens; and (3) the failure mechanism of the samples can be summarized into two categories: sliding along lamination and shearing of rock material, with the type occurring in a particular situation depending strongly on the lamination orientation angles with respect to the major principal stress. According to the findings, it is strongly recommended that the effect of anisotropy and water content on the strength and deformation behavior of the rock must be considered in ground control designs.

scholarly journals Characterization of the microstructural components and corrosion-induced changes in the mechanical properties of oolitic limestone

2020 ◽  
Vol 205 ◽  
pp. 03011
Author(s):  
Aránzazu Piñán-Llamas ◽  
Fawad S. Niazi ◽  
Colton Amstutz ◽  
Zachary Brown
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Exposure Time ◽  
Chemical Weathering ◽  
Young's Modulus ◽  
Triaxial Compression ◽  
Effective Porosity ◽  
Peak Strength ◽  
Stress Concentrations ◽  
Oolitic Limestone

The understanding of the variation of mechanical properties and microstructural changes of rocks due to chemical weathering is critical for prospection, extraction and storage of energy resources in the subsurface. Uniaxial and triaxial compression tests were conducted on fresh and chemically weathered oolitic limestone samples submerged in acidic solutions with pH5 and pH3 values for 30 and 50 days each. Results show that both, acid concentration and exposure period have a significant influence not only in changes of effective porosity, Young’s modulus and peak strength, but also in the development of stress-induced microstructures. While the change in effective porosity increased and the Young’s modulus decreased with exposure time, the peak strength decreased with exposure time and decreasing pH. Micro-fracturing, twinning, and rigid body rotation were the main mechanisms of the deformations observed. The highest density of microcracks and twinned grains were observed in samples subjected to longer exposure periods of time, suggesting that the exposure time constitutes an essential factor in rock softening. Microfracturing initiated at grain boundaries, where stress concentrations were higher. In agreement with previous work on limestone inelastic compaction, the mechanical contrast of allochemical components with respect to cement conditioned the spatial distribution of the microfractures.

scholarly journals Mechanical Properties and Environmental Evaluation of Ultra-High-Performance Concrete with Aeolian Sand

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3148 ◽  
Author(s):  
Hongyan Chu ◽  
Fengjuan Wang ◽  
Liguo Wang ◽  
Taotao Feng ◽  
Danqian Wang
Keyword(s):  
Compressive Strength ◽  
Environmental Impact ◽  
Young’S Modulus ◽  
High Performance ◽  
High Performance Concrete ◽  
Young's Modulus ◽  
Ultra High Performance Concrete ◽  
Aeolian Sand ◽  
Binder Ratio ◽  
Water Binder Ratio

Ultra-high-performance concrete (UHPC) has received increasing attention in recent years due to its remarkable ductility, durability, and mechanical properties. However, the manufacture of UHPC can cause serious environmental issues. This work addresses the feasibility of using aeolian sand to produce UHPC, and the mix design, environmental impact, and mechanical characterization of UHPC are investigated. We designed the mix proportions of the UHPC according to the modified Andreasen and Andersen particle packing model. We studied the workability, microstructure, porosity, mechanical performance, and environmental impact of UHPC with three different water/binder ratios. The following findings were noted: (1) the compressive strength, flexural strength, and Young’s modulus of the designed UHPC samples were in the ranges of 163.9–207.0 MPa, 18.0–32.2 MPa, and 49.3–58.9 GPa, respectively; (2) the compressive strength, flexural strength, and Young’s modulus of the UHPC increased with a decrease in water/binder ratio and an increase in the steel fibre content; (3) the compressive strength–Young’s modulus correlation of the UHPC could be described by an exponential formula; (4) the environmental impact of UHPC can be improved by decreasing its water/binder ratio. These findings suggest that it is possible to use aeolian sand to manufacture UHPC, and this study promotes the application of aeolian sand for this purpose.

scholarly journals Sea-Ice Investigations In The Weddell Sea During The German Antarctic Expedition 1979-80

1983 ◽  
Vol 4 ◽  
pp. 246-252 ◽  
Author(s):  
Joachim Schwarz
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Sea Ice ◽  
Young’S Modulus ◽  
Uniaxial Compressive Strength ◽  
Young's Modulus ◽  
Weddell Sea ◽  
Ice Shelves ◽  
Antarctic Expedition ◽  
Ice Conditions

In the austral winter of 1979-80, a German Antarctic expedition was sent by ship to the Filchner and Ronne ice shelves in order to find a suitable site for the establishment of a permanent Antarctic station. During this expedition, investigations were carried out on sea ice in the Weddell Sea in order to evaluate the accessibility of the site for icebreaking ships which are intended to convey construction materials to the site and, later on, to supply the station annually.This paper covers the results of investigations on sea-ice conditions during the voyage along the ice shelves from Cape Fiske (at the base of the Antarctic Peninsula) to Atka Bay with emphasis on sea-ice conditions in the area about 100 km north-west of Berkner Island (Fig.1.). In addition to the drift conditions (speed, direction), a special feature of multi-year sea ice is described. The main part of the paper deals with mechanical properties such as flexural strength, uniaxial compressive strength and Young’s modulus of columnar-grained sea ice from the southern border of the Weddell Sea. Salinities and temperatures were measured over the depth of the ice and used for calculating the flexural strength and the Young’s modulus of the ice. The uniaxial compressive strength was investigated as a function of strain-rate, brine volume and temperature on a closed-loop testing machine on samples which were carried back from Antarctica to Hamburg.

Phase Stability and Mechanical Properties of Ti-Cr-Sn-Zr Alloys Containing a Large Amount of Zr

2016 ◽  
Vol 879 ◽  
pp. 1344-1349 ◽  
Author(s):  
Yonosuke Murayama ◽  
Erdnechuluun Enkhjavkhlan ◽  
Akihiko Chiba
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Deformation Behavior ◽  
Single Phase ◽  
Young's Modulus ◽  
Martensitic Structure ◽  
Β Phase ◽  
Microstructural Transition ◽  
Zr Alloy ◽  
Zr Alloys

The Young’s modulus of Ti-Cr-Sn-Zr alloy varies with the composition of Cr, Sn and Zr, in which the elements act as β stabilizers. Some Ti-Cr-Sn-Zr alloys show very low Young’s modulus under 50GPa. The amount of Zr in alloys with very low Young's modulus increases with the decrease of Cr. We investigated the Young’s modulus and deformation behavior of Ti-xCr-Sn-Zr (x=0~1mass%) alloys containing a large amount of Zr. The quenched microstructure of Ti-Cr-Sn-Zr alloys changes from martensitic structure to β single-phase structure if the amounts of β stabilized elements are increased. The Ti-Cr-Sn-Zr alloys with compositions close to the transitional composition of microstructure from martensite to β phase show minimum Young’s modulus. The clear microstructural transition disappears and the minimum Young’s modulus increases if the amount of Cr becomes too small. In Ti-Cr-Sn-Zr alloys containing a large amount of Zr, Young’s modulus depends on β phase that is intermingled with martensite.

Experimental Study of Time-Frequency Effect of Rocks

2012 ◽  
Vol 204-208 ◽  
pp. 755-760
Author(s):  
Xin Lin Wan ◽  
Su Zhang
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Sine Wave ◽  
Intersection Point ◽  
Frequency Effect ◽  
Nonlinear Frequency ◽  
Time Frequency ◽  
Physical Mechanisms ◽  
Nonlinear Frequency Response ◽  
Water Saturated

Sine wave loading experiments are carried out on MTS for pump-oil saturated Nanjing sandstones and water saturated Dali marbles. The Young’s modulus and velocities of longitudinal wave and transverse wave increase with the frequency, and there are notable dispersions. The existence of micro defects in saturated rocks result in hysteresis at the sinusoidal loading experiments. The variation curves of instantaneous Young’s modulus with stress for loading and unloading intersect, and an “X” shape figure is obtained. As the frequency of the sinusoidal wave increases, the position of the intersection point moves to higher modulus area. Thus the modulus dispersion increases. Some physical mechanisms of nonlinear frequency response of rock are revealed. The results obtained are very important for nonlinear wave study, and the theoretical study and application of earthquake and engineering.

Materials for Well Integrity: Characterization of Short-Term Mechanical Properties

2020 ◽  
Author(s):  
Mohammadreza Kamali ◽  
Mahmoud Khalifeh ◽  
Arild Saasen ◽  
Laurent Delabroy
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Strength Reduction ◽  
Indirect Tensile Strength ◽  
Short Term ◽  
Indirect Tensile ◽  
Expansive Cement

Abstract Integrated zonal isolation is well-known as a key parameter for safe drilling operation and well completion of oil and gas wells. An extensive research on alternative materials has been conducted in the past concerning primary cementing, overcoming annular leaks, and permanent well abandonment. The present article focuses on geopolymers, expansive cement, pozzolan based sealant and thermosetting resins. The viscous behavior and the pumpability of the different materials have been investigated and benchmarked with the properties of neat class G Portland cement. The current study includes short-term mechanical properties of the above-mentioned materials. These properties include compressive strength development, Young’s modulus, indirect tensile strength, and sonic strength. The tests are performed in accordance with API 10B-2 and ASTM D3967-16 for all the materials for 1, 3, 5, and 7-day of curing at 90°C and elevated (172 bar) and atmospheric pressures. Our results show a mixed behavior from the materials. According to uniaxial compressive test results, all the candidate barrier materials developed strength during the considered period; however, the geopolymer and pozzolanic-based mixture did not develop early strength. The expansive cement showed an acceptable early compressive strength, but strength reduction was noticed after some time. The strength reduction of expansive cement was also observed for the indirect tensile strength. All the materials become stiffer overtime as they made more strength. For the neat class G cement and expansive cement, the Young’s modulus showed a minimum after 5 days, but it was increased.

Sea-Ice Investigations In The Weddell Sea During The German Antarctic Expedition 1979-80

1983 ◽  
Vol 4 ◽  
pp. 246-252
Author(s):  
Joachim Schwarz
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Sea Ice ◽  
Young’S Modulus ◽  
Uniaxial Compressive Strength ◽  
Young's Modulus ◽  
Weddell Sea ◽  
Ice Shelves ◽  
Antarctic Expedition ◽  
Ice Conditions

In the austral winter of 1979-80, a German Antarctic expedition was sent by ship to the Filchner and Ronne ice shelves in order to find a suitable site for the establishment of a permanent Antarctic station. During this expedition, investigations were carried out on sea ice in the Weddell Sea in order to evaluate the accessibility of the site for icebreaking ships which are intended to convey construction materials to the site and, later on, to supply the station annually.This paper covers the results of investigations on sea-ice conditions during the voyage along the ice shelves from Cape Fiske (at the base of the Antarctic Peninsula) to Atka Bay with emphasis on sea-ice conditions in the area about 100 km north-west of Berkner Island (Fig.1.). In addition to the drift conditions (speed, direction), a special feature of multi-year sea ice is described. The main part of the paper deals with mechanical properties such as flexural strength, uniaxial compressive strength and Young’s modulus of columnar-grained sea ice from the southern border of the Weddell Sea. Salinities and temperatures were measured over the depth of the ice and used for calculating the flexural strength and the Young’s modulus of the ice. The uniaxial compressive strength was investigated as a function of strain-rate, brine volume and temperature on a closed-loop testing machine on samples which were carried back from Antarctica to Hamburg.

Frequency-dependent attenuation in water-saturated cracked glass based on creep tests

Geophysics ◽  
2017 ◽  
Vol 82 (3) ◽  
pp. MR89-MR96 ◽  
Author(s):  
Céline Mallet ◽  
Beatriz Quintal ◽  
Eva Caspari ◽  
Klaus Holliger
Keyword(s):  
Young’S Modulus ◽  
Glass Sample ◽  
Young's Modulus ◽  
Axial Stress ◽  
Creep Tests ◽  
Crack Network ◽  
Frequency Dependent ◽  
Essential Information ◽  
Poroelastic Model ◽  
Water Saturated

We estimate attenuation at subseismic frequencies from an experimental creep test performed on a thermally cracked water-saturated glass sample. The time-dependent axial stress and strain rates are used to infer the attenuation and Young’s modulus as functions of frequency. Attenuation is characterized by a pronounced frequency dependence between [Formula: see text] and [Formula: see text]. A corresponding frequency-dependent behavior of the Young’s modulus is observed with an increase from 60 to 70 GPa, which is consistent with the measured static and ultrasonic values. These observations are interpreted as being due to fluid flow between interconnected cracks in the mesoscopic scale range. To test this hypothesis, we compare the analytical characteristic frequency for the presumed mesoscopic squirt-type flow with its experimental counterpart. We also compare the experimentally observed attenuation characteristics with results of numerical simulations. For the latter, a thin section of the cracked glass sample has been digitized to provide essential information with regard to the geometry of the crack network. Together with the known physical properties of the intact glass matrix, this then allows for deriving a first-order 2D poroelastic model for the cracked sample based on Biot’s quasi-static equations.

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