Triaxial Testing of Freshwater Ice at Low Confining Pressures

1991 ◽  
Vol 113 (3) ◽  
pp. 260-265 ◽  
Author(s):  
J. P. Nadreau ◽  
A. M. Nawwar ◽  
Y. S. Wang
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Confining Pressure ◽  
Peak Temperature ◽  
Triaxial Testing ◽  
Brittle Transition ◽  
Freshwater Ice ◽  
Triaxial Compressive Strength ◽  
Confining Pressures ◽  
Ductile To Brittle Transition

Tests have been conducted on freshwater columnar ice samples to determine the uniaxial and triaxial compressive strength of the ice. Four parameters were varied. The confining pressure was increased up to 2.85 MPa (400 psi) in steps of 0.7 MPa (100 psi). The strain rate was varied in order to obtain the ductile to brittle transition peak. Temperature was kept mainly at −2°, with two series at −10°C and −20°C, and samples were machined with axes parallel, perpendicular or at a 45-deg angle to the direction of ice growth. The results are presented within their original context, but analyzed with reference to recent studies conducted on the multiaxial behavior of ice.

scholarly journals Experimental Study on Triaxial Unloading Failure of Deep Composite Coal-Rock

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xin Li ◽  
Hao Li ◽  
Zhen Yang ◽  
Zhongxue Sun ◽  
Jiayu Zhuang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Failure Criterion ◽  
Confining Pressure ◽  
Exponential Relationship ◽  
Partial Fracture ◽  
Triaxial Compressive Strength ◽  
Confining Pressures ◽  
Unloading Rate ◽  
Coal Rock ◽  
And Control

With the deep mining of coal, the phenomenon of high ground stress is more likely to cause dynamic disaster. In view of the above problems, this paper takes the unloading process of coal mining as the background to study the effects of mining rates under different conditions on the mechanical properties and triaxial failure criterion of composite coal-rock, so as to provide a theoretical basis for the prevention and control of dynamic disasters in coal mines. The composite coal-rock models with a composite ratio of 1 : 1 : 1 were tested under different unloading rates or confining pressures. The results show that the triaxial unloading process of coal-rock can be divided into five stages: compaction, single elasticity, elastic-plastic unloading, partial fracture, and complete fracture. In this paper, the failure criterion of composite coal-rock triaxial unloading is derived. The unloading rate has an exponential relationship with the triaxial compressive strength, and the relationship between initial confining pressure and compressive strength is linear. The triaxial compressive strength is determined by both. The peak strains ε of all samples under different unloading conditions were around 0.01. And initial confining pressure had an influence on the strain variation trend during the unloading of composite coal-rock. The higher the initial confining pressure, the greater the elastic modulus. In addition, an increase of initial confining pressure led to the increase of the total energy converted into dissipated part in the process of fracture and caused the obvious increase of the rebound characteristics of the curve. However, the unloading rate had no influence on the strain trend.

scholarly journals The Confined Compressive Strength of Polycrystalline Ice

1982 ◽  
Vol 28 (98) ◽  
pp. 171-178 ◽  
Author(s):  
Stephen J. Jones
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Strain Rates ◽  
Maximum Compressive Stress ◽  
A Value ◽  
Polycrystalline Ice ◽  
Confining Pressures ◽  
Unconfined Strength

AbstractTriaxial tests were carried out on randomly oriented, laboratory-made, polycrystalline ice, between strain-rates of 10–7 and 10–1 s–1 and with confining pressures from 0.1 to 85 MN m–2, at –11 ± 1°C. Below strain-rates of about 10–5 s–1 the confining pressure has little effect, but at higher strain-rates the confining pressure prevents cracking which allows the compressive strength to rise to a value greater than the unconfined compressive strength. At 1.4 ×10–2 s–1, the unconfined strength of 12 MN m–2 rises to 26 MN m–2 with a confining pressure of 25 MN m–2, before dropping slowly with greater confining pressures. Above 10–2 s–1 the unconfined strength decreases rapidly with increasing strain-rate, but the confined strength continues to increase. The dependence of strain rate on the maximum compressive stress is discussed.

scholarly journals Experimental Investigation on Permeability Evolution of Dolomite Caprock under Triaxial Compression

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6535
Author(s):  
Deng Xu ◽  
Jianfeng Liu ◽  
Zhide Wu ◽  
Lu Wang ◽  
Hejuan Liu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Test Machine ◽  
Permeability Evolution ◽  
Triaxial Compressive Strength ◽  
Confining Pressures ◽  
Porosity And Permeability ◽  
The Difference ◽  
Maximum Permeability

In order to study the influence of different confining pressures on the stability and airtightness of dolomite underground gas storage, a permeability test under hydrostatic confining pressure, conventional triaxial compression test and gas–solid coupling test under triaxial compression were carried out on MTS815 test machine. During the tests, an acoustic emission (AE) monitoring system was also employed to estimate the rock damage. The experimental results showed that the relationships between permeability, porosity and hydrostatic confining pressure were exponential function and power function, respectively. Increasing confining pressure reduced the porosity and permeability of dolomite, and increased its triaxial compressive strength, but the addition of nitrogen reduced the compressive strength of dolomite by 10~30%, the higher the confining pressure, the smaller the difference. Compared with the maximum permeability under 15 MPa, confining pressure in the gas–solid coupling experiment, the maximum permeability under confining pressure of 30, 45, and 60 MPa is reduced by 42.0%, 84.4%, and 97.9%, respectively. In addition, the AE activity of dolomite decreases significantly with the increase in confining pressure, which also delayed the arrival of the AE active period.

scholarly journals The Confined Compressive Strength of Polycrystalline Ice

1982 ◽  
Vol 28 (98) ◽  
pp. 171-178 ◽  
Author(s):  
Stephen J. Jones
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Strain Rates ◽  
Maximum Compressive Stress ◽  
A Value ◽  
Polycrystalline Ice ◽  
Confining Pressures ◽  
Unconfined Strength

Abstract Triaxial tests were carried out on randomly oriented, laboratory-made, polycrystalline ice, between strain-rates of 10–7 and 10–1 s–1 and with confining pressures from 0.1 to 85 MN m–2, at –11 ± 1°C. Below strain-rates of about 10–5 s–1 the confining pressure has little effect, but at higher strain-rates the confining pressure prevents cracking which allows the compressive strength to rise to a value greater than the unconfined compressive strength. At 1.4 ×10–2 s–1, the unconfined strength of 12 MN m–2 rises to 26 MN m–2 with a confining pressure of 25 MN m–2, before dropping slowly with greater confining pressures. Above 10–2 s–1 the unconfined strength decreases rapidly with increasing strain-rate, but the confined strength continues to increase. The dependence of strain rate on the maximum compressive stress is discussed.

scholarly journals Investigation of the Mechanical Properties of St. Lawrence River Ice

1971 ◽  
Vol 8 (2) ◽  
pp. 163-169 ◽  
Author(s):  
L. W. Gold ◽  
A. S. Krausz
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Yield Stress ◽  
Power Law ◽  
River Ice ◽  
Stress Strain ◽  
Strain Behavior ◽  
Brittle Transition ◽  
Ductile To Brittle Transition ◽  
St Lawrence River

Observations are reported on the stress–strain behavior at −9.5 ± 0.5 °C of four types of ice obtained from the St. Lawrence River. The ice was subject to nominal rates of strain covering the range 2.1 × 10−5 min−1 to 5.8 × 10−2 min−1. A ductile-to-brittle transition was observed for strain rate of about 10−2 min−1. In the ductile range the four types had an upper yield stress that increased with strain rate according to a power law.

scholarly journals Physical and Mechanical Properties of a Bulk Lightweight Concrete with Expanded Polystyrene (EPS) Beads and Soft Marine Clay

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1662 ◽  
Author(s):  
Jianguo Wang ◽  
Bowen Hu ◽  
Jia Hwei Soon
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cement Content ◽  
Mass Density ◽  
Physical And Mechanical Properties ◽  
Confining Pressure ◽  
Expanded Polystyrene ◽  
Triaxial Tests ◽  
Filling Material ◽  
Confining Pressures

The variation of physical and mechanical properties of the lightweight bulk filling material with cement and expanded polystyrene (EPS) beads contents under different confining pressures is important to construction and geotechnical applications. In this study, a lightweight bulk filling material was firstly fabricated with Singapore marine clay, ordinary Portland cement and EPS. Then, the influences of EPS beads content, cement content, curing time and confining pressure on the mass density, stress–strain behavior and compressive strength of this lightweight bulk filling material were investigated by unconsolidated and undrained (UU) triaxial tests. In these tests, the mass ratios of EPS beads to dry clay (E/S) were 0%, 0.5%, 1%, 2%, and 4% and the mass ratios of cement to dry clay (C/S) were 10% and 15%. Thirdly, a series of UU triaxial tests were performed at a confining pressure of 0 kPa, 50 kPa, 100 kPa, and 150 kPa after three curing days, seven curing days, and 28 curing days. The results show that the mass density of this lightweight bulk filling material was mainly controlled by the E/S ratio. Its mass density decreased by 55.6% for the C/S ratio 10% and 54.9% for the C/S ratio 15% when the E/S ratio increased from 0% to 4% after three curing days. Shear failure more easily occurred in the specimens with higher cement content and lower confining pressure. The relationships between compressive strength and mass density or failure strain could be quantified by the power function. Increasing cement content and reducing EPS beads content will increase mass density and compressive strength of this lightweight bulk filling material. The compressive strength with curing time can be expressed by a logarithmic function with fitting correlation coefficient ranging from 0.83 to 0.97 for five confining pressures. These empirical formulae will be useful for the estimation of physical and mechanical properties of lightweight concretes in engineering application.

Uniaxial Compressive Strengths of Artificial Freshwater Ice

2011 ◽  
Vol 243-249 ◽  
pp. 4634-4637 ◽  
Author(s):  
Li Min Zhang ◽  
Zhi Jun Li ◽  
Qing Jia ◽  
Guang Wei Li ◽  
Wen Feng Huang
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Uniaxial Compression Test ◽  
Strain Rates ◽  
Precise Control ◽  
Freshwater Ice ◽  
Ice Surface ◽  
Loading Direction ◽  
Maximum Value ◽  
Lower Strain

The uniaxial compression test was performed on artificial freshwater ice with a precise control-temperature unit compression tester of ice under -5, -10, -15, -20 and-30°C temperatures and strain rates ranging from 10-8 to 10-2 s-1. The loading direction was parallel to ice surface. The results showed that the compressive strength was very sensitive to the strain-rate. The uniaxial compressive strengths reached the maximum value at the ductile-brittle transition region, and the region was gradually close to the lower strain-rate with the decreasing temperature of test. Both the strain-rate and uniaxial compressive strength dependences could be expressed in terms of power function in the relevant ductile range of strain-rate. The tests also revealed that failure stress of ice increases with decreasing of temperature at the same strain rate.

Effect of Strain Rate on Ductile-to-Brittle Transition Temperature of a Free-Standing Pt-Aluminide Bond Coat

2011 ◽  
Vol 42 (6) ◽  
pp. 1431-1434
Author(s):  
Md. Zafir Alam ◽  
D. Chatterjee ◽  
K. Muraleedharan ◽  
T. K. Nandy ◽  
S. V. Kamat ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Strain Rate ◽  
Bond Coat ◽  
Free Standing ◽  
Brittle Transition ◽  
Brittle Transition Temperature ◽  
Ductile To Brittle Transition
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