Wyniki wyszukiwania - Biblioteka Nauki

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Mathematical model for the capacity of the mud flow with wave regime taking into account its rheological properties

100%

Gavardashvili G. , Kukhalashvili E. , Kurtsikidze N. , Dadiani K.

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tom Vol. 33, No. 3

278--287

EN

The paper presents particular issues of mudflow dynamics, one of the hazardous natural disasters, namely the theoretical study of the flow power during mudflow movement in the wave regime taking into account its rheological properties. The paper discusses the physical process of mudflow mass impetus accumulated in erosion banks, taking into account the impact of the tense state of the eroded mass, in particular, similar to soil mechanics problems, the density of the mudflow-forming mass (ρ), the free fall acceleration (g), angle of internal friction (φ), the adhesive force (Pe), the height equivalent to pressure (h′), the height of the mudflow-forming mass (H), the intensity of transverse pressure (P), and the value of the active pressure of the inertial mass cohesion (C) on the deformation mode of the mudflow mass. On the basis of the basic equations of mudflow dynamics and theoretical studies, an equation is obtained to calculate the values of flow power when mudflows move in the wave mode, taking into account the main rheological properties of a mudflow mass.

2

The age of the oldest Paleolithic assemblages from Biśnik Cave (southern Poland) in the light of geological data

86%

Krajcarz M. T. , Cyrek K.

Przegląd Archeologiczny

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2011

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tom 59

55-74

EN

Biśnik Cave is a multi-layer site, which contains one of the oldest Paleolithic settlement levels in Poland. The character of the oldest inventory from the cave is depicted by the domination of the Levallois technique for obtaining flakes and blades. The tools included: forms with one side preparation technique connected with different types of side scrapers and small side scrapers, denticulate and notch forms. Bifacial artifacts are absent. Because of a small number of the inventory, we can only conclude that it is a typological collection of artifacts characteristic of the Mousterian tradition, broadly speaking. The oldest assemblages were found in Layers 19a, 19b, 19c and 19d. Sedimentological analysis show that the whole of Layers 19b-19c-19d should be treated as a deluvial sediment resulting from the series of several mudslides. The same interpretation could be concluded on the basis of geochemical data acquired for bone remains. Flint objects found in Layer 19a are the oldest artifacts in the position in situ. The date obtained for the Layer 19a (230 ± 51 ka) lets us determine the approximate age of the sediment and artifacts, which is oxygen isotope stage OIS 7. All of the older artifacts found in Layers 19d and 19b-19c are located on the secondary deposit. The TL date obtained for the sediment of one of the deluvial layers (569 ± 182 ka), as well as the date obtained for the burned flint tool (568 ± 131 ka) point to the early Middle Pleistocene age of at least some of the redeposited sediments and artifacts.

3

Gradually varied flow of unloaded mud in open channel

86%

Nsom B. , Debiane K. , Piau J. M. , Ayadi A.

Applied Mechanics and Engineering

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1999

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tom Vol. 4, no 3

443-470

EN

We present a theoretical and experimental study of unloaded free surface mudflow in gradually varied conditions. First of all, a polymer gel following the same rheological law as the natural mud was identified, and its severe rheometric characterization was performed. Then the flow of this synthetic mud was generated in a 1-D open channel. The velocity and depth profiles were then systematically investigated. The theoretical study consisted in determining the velocity profiles in terms of the rheological parameters in uniform conditions as well as in determining the form parameter characterizing the gradually varied flow of yield stress fluids in open channels.

4

Evaluation of the environmental safety of small Kazbegi HPP by considering the action of Devdorak glacier formed in the bed of the river Kabakhi (Georgia)

72%

Gavardashvili G. , Chakhaia G. , Tsulukidze L. , Kapezina O.

Budownictwo o Zoptymalizowanym Potencjale Energetycznym

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2015

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tom nr 1(15)

55--60

EN

Aiming at assessing the environmental safety of small Kazbegi HPP, we have described the catastrophic-scale mudflow formed as a result of movement of Devdorak glacier in the Gorge of the river Kabakhi (left tributary of the river Tergi) on May 17, 2014, which inflicted significant damage to the hydraulic works of Kazbegi HPP. With the purpose of securing the environmental safety of small Kazbegi HPP and regulating the erosive-mudflow processes inter alia, the performance reliability and risk of breakdown of a new springboard-type structure by considering the dynamic and static loads of the mudflow were specified.

PL

Mające na uwadze ocenę bezpieczeństwa środowiskowego małej elektrowni wodnej Kazbegi opisano katastroficzną skalę lawiny mieszanej utworzonej w wyniku przemieszczania się lodowca Devdorak w wąwozie rzeki Kabakhi (lewy dopływ rzeki Tergi) w Gruzji 17 maja 2014 r., która spowodowała znaczne uszkodzenia w elektrowni Kazbegi. W celu zapewnienia bezpieczeństwa środowiskowego elektrowni Kazbegi i regulacji procesu powstawania lawin między innymi określono niezawodność i ryzyko wystąpienia awarii nowego typu konstrukcji przy uwzględnieniu dynamicznych i statycznych obciążeń od lawiny mieszanej.