Pressure‐dependent seismic velocities based on unified asperity‐deformation model

2011 ◽  
Author(s):  
Kai Gao ◽  
Richard L. Gibson
Keyword(s):  
Deformation Model ◽  
Seismic Velocities ◽  
Asperity Deformation

An asperity-deformation model for effective pressure

1996 ◽  
Vol 256 (1-4) ◽  
pp. 241-251 ◽  
Author(s):  
Anthony F. Gangi ◽  
Richard L. Carlson
Keyword(s):  
Deformation Model ◽  
Effective Pressure ◽  
Asperity Deformation

Pressure-dependent seismic velocities based on effective compliance theory and an asperity deformation model

Geophysics ◽  
2012 ◽  
Vol 77 (6) ◽  
pp. D229-D243 ◽  
Author(s):  
Kai Gao ◽  
Richard L. Gibson
Keyword(s):  
Pressure Dependence ◽  
Laboratory Data ◽  
Confining Pressure ◽  
Time Lapse ◽  
Hertzian Contact ◽  
Deformation Model ◽  
Seismic Velocities ◽  
Power Law Distribution ◽  
S Wave ◽  
Effective Compliance

Seismic velocities of rocks depend strongly on confining pressure, which is often explained by the fracture compliances changes within the rocks. It is important to have an accurate model describing the relations between confining pressure and seismic velocities for applications such as time-lapse reservoir characterization. We propose a new model to address this problem by combining the existing effective compliance theory with new solutions for the pressure dependence of fracture compliances. Specifically, we assume the fracture contact surface can be represented by a set of elastic hemispheres with radii following power-law distribution, and the pressure dependence of seismic velocities can be expressed through pressure-dependent normal and tangential fracture compliances that are derived from Hertzian contact theory. Joint data fittings of P- and S-wave velocity laboratory data show that our model is accurate. We also implement fluid substitution using our model to explain the similar stress-induced velocity variations of fluid-saturated fractured rocks.

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.

Method of construction of the predictive deformation model of the edge zone of the career in the rock massif

2018 ◽  
Vol 1 (1) ◽  
pp. 72-78
Author(s):  
Godovnikov N.A. ◽  
◽  
Dunaev V.A. ◽  
Ignatenko I.M. ◽  
◽  
...  
Keyword(s):  
Rock Massif ◽  
Deformation Model ◽  
Edge Zone

Methodology of studying the mechanical properties of composite materials (reinforced concrete)

2018 ◽  
Vol 84 (12) ◽  
pp. 61-67
Author(s):  
V. A. Eryshev
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Experimental Studies ◽  
Analytical Relationship ◽  
Hardened Concrete ◽  
Deformation Model ◽  
Joint Work ◽  
Concrete Shrinkage ◽  
Axial Tension ◽  
Tension And Compression

The mechanical properties of a complex composite material formed by steel and hardened concrete, are studied. A technique of operative quality control of new credible concrete and reinforcement, both in laboratory and field conditions is developed for determination of the strength and strain characteristics of materials, as well as cohesion forces determining their joint operation under load. The design of the mobile unit is presented. The unit provides a possibility of changing the direction of loading and testing the reinforced element of the given shape both for tension and compression. Moreover, the nomenclature of testing equipment and the number of molds for manufacturing concrete samples substantially decrease. Using the values of forcing resulting in concrete cracking when the joint work of concrete and reinforcement is disrupted the values of the inherent stresses and strains attributed to the concrete shrinkage are determined. An analytical relationship between the forces and deformations of the reinforced concrete sample with central reinforcement is derived for axial tension and compression, with allowance for strains and stresses in the reinforcement and concrete resulted from concrete shrinkage. The results of experimental studies are presented, including tension diagrams and diagrams of developing axial deformations with an increase in the load under the central loading of the reinforced elements. A methodology of accounting for stresses and deformations resulted from concrete shrinkage is developed. The applicability of the derived analytical relationships between stresses and deformations on the material diagrams to calculations of the reinforced concrete structures in the framework of the deformation model is estimated.

Inferred fault geometry and slip distribution of the 2010 Jiashian, Taiwan, earthquake is consistent with a thick-skinned deformation model

2011 ◽  
Vol 301 (1-2) ◽  
pp. 78-86 ◽  
Author(s):  
Kuo-En Ching ◽  
Kaj M. Johnson ◽  
Ruey-Juin Rau ◽  
Ray Y. Chuang ◽  
Long-Chen Kuo ◽  
...  
Keyword(s):  
Slip Distribution ◽  
Deformation Model ◽  
Fault Geometry ◽  
Taiwan Earthquake
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