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Extracting static elastic moduli of rock through elastic wave velocities

Zhang Yuliang, Gu Yiming, Zhou Hongtu, Yang Lining

Acta Geophysica

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2024

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Vol. 72, no. 2

915--931

EN

In many geological conditions, obtaining the static elastic moduli of crustal rocks is an essential subject for accurate mechanical analyses of crust. The elastic wave method may be the best choice if rock specimens cannot be taken since elastic wave propagation can be applied to in-situ environments. Although many signs of progress have been made in the elastic wave method, some issues still restrict the accurate extraction of static moduli and its applications. A review of this method and its further research prospect is urgently needed. With this purpose, this paper summarized and analyzed the published experimental data about the relationship between the static and dynamic Young’s moduli of rock, and the frequency dependence of wave velocities and dynamic elastic moduli. P- and S-wave velocities, Young’s, and bulk moduli of rock, especially the saturated rock, have strong frequency dependence in a wide frequency range of 10-6-106 Hz. Different rocks or conditions (such as water content, amplitude, and pressure), have different frequency-dependent characteristics. The current elastic wave method can be classified into two methods: the empirical correlation method and the multifrequency ultrasonic method. The basic principle, advantages, and disadvantages of both methods are analyzed. Especially, the reasonability of the multifrequency ultrasonic method was elaborated given the nonlinear elasticity, strain level/rate, and pores/cracks in rock materials. Existing problems and prospects on the two methods are also pointed out, such as the choice of a proper empirical correlation, accurate determination of the critical P- and S-wave velocities, the prediction of Young’s modulus at each strain level, and the reasonability of the method under various water contents and fracture structures.

2

Diagnostyka konstrukcji betonowych po działaniu wysokich temperatur pożarowych (cz. 1)

Plechawski Stanisław

Budownictwo i Prawo

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2021

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R. 25, nr 3

7--10

PL

W artykule zaprezentowano wybrane metody określania wpływu wysokich temperatur pożarowych na nośność konstrukcji betonowych – diagnostykę oraz uszkodzenia powstające po działaniu tych temperatur. Istotną kwestią poruszoną w artykule jest wpływ pożaru na odporność betonu na pękanie i jej zależność od wysokich temperatur. Destrukcje powstające pod wpływem wysokich temperatur pożarowych definitywnie wpływają na mechanikę pękania betonu, a ich wielkość może być oceniana za pomocą współczynnika intensywności naprężeń. W artykule opisano wybrane metody diagnostyki elementów konstrukcyjnych z betonu uszkodzonych przez pożar.

EN

The article presents selected methods of determining the effect of high fire temperatures on the load-bearing capacity of concrete structures – diagnostics and damage occurring after the application of these temperatures. An important issue discussed in the article is the influence of fire on the cracking resistance of concrete and its dependence on high temperatures. Failures occurring under the influence of high fire temperatures definitely affect the fracture mechanics of concrete, and their magnitude can be assessed by means of the stress intensity factor. This paper describes selected methods for diagnosing structural elements made of concrete damaged by fire.

3

Metoda wyznaczania dynamicznego modułu sprężystości betonu z wykorzystaniem impulsowego wzbudzenia drgań i analizy modalnej

Jurowski K., Kokot S., Bobra P., Grzeszczyk S.

Inżynieria i Budownictwo

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2016

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R. 72, nr 11

612--615

PL

Porównano normowe procedury wyznaczania dynamicznego modułu sprężystości betonu. W celu sprawdzenia poprawności proponowanych w normach procedur obliczeniowych dokonano analizy wyników badań próbek z różnego rodzaju betonów o różnych wymiarach gabarytowych.

EN

A comparison of standard procedures of dynamic elastic modulus testing is provided. In order to check the correctness of the calculation methods proposed by the standards an analysis of samples of different kinds of concrete of different sizes is presented.

4

Influence of water adsorption on mechanical properties of porous glasses.

Rysiakiewicz-Pasek E.

Optica Applicata

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2000

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Vol. 30, nr 1

173-176

EN

An influence of different treatment of porous glass (water adsorption, heat or hexamethyldisilazane treatment) on the values of elasticity parameters was investigated. The laboratory ultrasonic tests were used to determine the dynamical elastic modulus. The observed changes of the dynamic elastic modulus of porous glasses were related with processes of adsorption and desorption of water from the pores.