The relationship between generalized preconsolidation pressure and brittle-ductile transition pressure in sedimentary soft rock

AbstractWe simulate fracture in two amorphous solids with different inter-particle potentials. These small changes in potential result in significant changes in dissipation near the crack tip. While one might expect these effects to arise from a change in flow stress, measurements reveal this is not the case. To understand why, we consider the relationship between crack dynamics, rate-dependent plasticity, and molecular-level structures in the glassy solid. In particular we discuss the macro-scale continuum theory of dynamic brittle fracture in a viscoplastic solid developed by Freund and Hutchinson and the meso-scale theory of viscoplasticity proposed by Falk and Langer. We further consider a simplified model on the molecular scale as a first-step toward the construction of first-principles models of dynamic plasticity and the brittle ductile transition in noncrystalline materials.

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On the relationship betweenPandS‐wave velocities in soft rock

10.1190/1.1826857 ◽

1982 ◽

Cited By ~ 1

Author(s):

Masayoshi Yoshimura ◽

Seishi Fujii ◽

Kenji Tanaka ◽

Ken Morita

Keyword(s):

Soft Rock ◽

Wave Velocities ◽

The Relationship

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Determination of Shape Coefficient in Elastic Modulus Estimation with Penetration Test

Advances in Civil Engineering ◽

10.1155/2021/6610607 ◽

2021 ◽

Vol 2021 ◽

pp. 1-6

Author(s):

Tongbin Zhao ◽

Rui Mao ◽

Kai Fang ◽

Biwen Zhang ◽

Fenghai Yu

Keyword(s):

Elastic Modulus ◽

Soft Rock ◽

Confining Pressure ◽

Test Results ◽

Penetration Test ◽

Shape Coefficient ◽

Penetration Behavior ◽

Penetration Tests ◽

The Relationship

Elastic modulus is a significant parameter in design and construction for rock engineering. Rock penetration test as a convenient method to evaluate the modulus of rocks has a great potential to be used. Based on the elastic theory, the relationship between rock penetration behavior and elastic modulus was established. In order to evaluate the elastic modulus, the shape coefficient is an important parameter to be determined. However, due to many factors, the value of this parameter is still uncertain. To provide a better insight into the shape coefficient and its factors, a series of penetration tests which used several types of rock samples with different sizes were conducted to study the determination of shape coefficient under different conditions. The test results show that sample size influences the shape coefficient, and with the increase in size, the shape coefficient decreases gradually to a stable value. In contrast, confining pressure has less effect on shape coefficient, and in the moderate and low stresses region, a fixed value can be selected for the test. Different types of rocks correspond to different shape coefficients. The shape coefficient of hard rock is higher than that of soft rock. Shape coefficient should be selected reasonably according to the penetration depth in practical application, and the reason, furthermore, why back-calculated shape coefficient deviates from the theoretical value is also discussed.

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Evaluation of the Elasticity of Clay Soils

Canadian Geotechnical Journal ◽

10.1139/t73-058 ◽

1973 ◽

Vol 10 (4) ◽

pp. 632-642

Author(s):

Mohamed K. Elsamny

Keyword(s):

Elastic Modulus ◽

Clay Soils ◽

Mathematical Treatment ◽

Hopkinson Pressure Bar ◽

Dynamic Approach ◽

Soil Response ◽

Preconsolidation Pressure ◽

Pressure Bar ◽

Available Information ◽

The Relationship

A dynamic approach is used to evaluate the elasticity of clay soils. The experimental technique employed in the work is a modification of the Hopkinson pressure bar. Tests covering an appropriate range of stress levels were carried out on laboratory prepared specimens representing a variety of preconsolidation pressures. On the basis of the available information, using the Hopkinson bar technique, conclusions with regard to the relationship between the preconsolidation pressure of the soil tested and the elastic modulus for different rates of deformation are drawn. Also, the dynamic soil response of the soil tested and its relationship to the preconsolidation pressure are presented. A mathematical treatment of the relationship between the elastic modulus and the consolidation pressure is also presented which is verified experimentally using the pressure bar technique.

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On the brittle-ductile transition pressure

Acta Metallurgica ◽

10.1016/0001-6160(67)90082-x ◽

1967 ◽

Vol 15 (3) ◽

pp. 497-500 ◽

Cited By ~ 10

Author(s):

R.J Dower

Keyword(s):

Transition Pressure ◽

Brittle Ductile Transition

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Study on the fractal model of water immersed collapse of Soft Rock

10.7764/rdlc.19.3.486-491 ◽

2020 ◽

Vol 19 (3) ◽

pp. 486-491

Author(s):

Lujun Ding ◽

◽

Yuhong Liu

Keyword(s):

Fractal Dimension ◽

Fractal Geometry ◽

Water Immersion ◽

Soft Rock ◽

Fractal Model ◽

Engineering Practice ◽

Rock Disintegration ◽

Water Swelling ◽

The Relationship ◽

Development And Evolution

Soft rock is a common rock mass in engineering, one of its characteristics is water swelling and disintegration. In this paper, the nonlinear fractal geometry is introduced and the correlation fractal dimension is used to study the characteristics of slate disintegration, based on the laboratory test of water immersion disintegration, the method of quality fractal dimension is used to solve the fractal dimension of the disintegration of slate, and the change of fractal dimension is used to reflect the characteristics of the softening and disintegration of slate when encountering water. The experimental results show that the fractal model can be used to fully understand the development and evolution of rock disintegration process, and to quantitatively link the relationship between rock expansion and disintegration. The conclusion has guiding significance for engineering practice.

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Toughening poly(3-hydroxybutyrate) with propylene carbonate plasticized poly(propylene carbonate)

e-Polymers ◽

10.1515/epoly-2013-0069 ◽

2014 ◽

Vol 14 (4) ◽

pp. 283-288 ◽

Cited By ~ 4

Author(s):

Linyao Zhou ◽

Guiyan Zhao ◽

Jinghua Yin ◽

Wei Jiang

Keyword(s):

Mechanical Properties ◽

Transition Temperature ◽

Young’S Modulus ◽

Propylene Carbonate ◽

Young's Modulus ◽

Brittle Ductile Transition ◽

Dispersed Particles ◽

Lower Temperature ◽

Poly Propylene ◽

The Relationship

AbstractPoly(3-hydroxybutyrate) (PHB)/poly(propylene carbonate) (PPC) blends containing various amounts of plasticizer propylene carbonate (PC) were prepared, and the toughness of the blends as a function of temperature was studied. It was found that the brittle-ductile transition temperature (TBD) of PHB toughened by PPC decreased from 60°C to 10°C with the increase in PC content. As PC is the plasticizer of PPC, the mechanical properties, such as Young’s modulus of plasticized PPC with different PC contents, were also studied. Sequentially, the relationship between TBD and the ratio of the Young’s modulus (E1) of the PHB matrix to that of the plasticized PPC elastomer (E2) was investigated. It was found that the Young’s modulus of plasticized PPC should be considerably lower than that of the PHB matrix in order to obtain ’the tough PHB/plasticized PPC blends at a lower temperature. In contrast, the morphology of the dispersed particles also had an important influence on the toughness. When the plasticizer content was more than 20 wt.%, the PPC particles became more spherical and smaller. The toughness could be considerably improved accordingly.

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Interstellar gas in the central region of the Galaxy

Symposium - International Astronomical Union ◽

10.1017/s0074180900101032 ◽

1967 ◽

Vol 31 ◽

pp. 239-251 ◽

Cited By ~ 3

Author(s):

F. J. Kerr

Keyword(s):

Central Region ◽

Galactic Plane ◽

Neutral Hydrogen ◽

Continuum Emission ◽

Galactic Centre ◽

Interstellar Gas ◽

Hydrogen Recombination ◽

The Galaxy ◽

Centre Region ◽

The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

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