Wyniki wyszukiwania - Biblioteka Nauki

1

The influence of curing time on the shear strength of fluidized fly ash

100%

Gruchot A.

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2015

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tom 47

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nr 2

EN

The influence of curing time on the shear strength of fluidized fly ash. The paper presents results of research on the influence of compaction and air and water curing on angle of internal friction and cohesion of fluidized fly ash from “Połaniec” Power Plant. It was stated that the increase in compaction resulted in an insignificant increase of the angle of internal friction and a quite signifi cant increase of cohesion. While the type and time of curing had a great influence on the angle of internal friction and cohesion. The highest values of angle of internal friction were obtained in the air curing, and the lowest in the water curing whereas in case of cohesion there was an inverse relation. The rise of curing time resulted in largely increased cohesion and small changes of angle of internal friction.

PL

W pracy przedstawiono wyniki badań wpływu zagęszczenia oraz czasu pielęgnacji powietrznej i wodnej na kąt tarcia wewnętrznego i spójność fluidalnego popiołu lotnego ze zsypu Elektrowni „Połaniec”. Stwierdzono, że wzrost zagęszczenia spowodował niewielkie zwiększenie wartości parametrów wytrzymałości na ścinanie. Rodzaj pielęgnacji i jej czas miały natomiast decydujący wpływ na wartości kąta tarcia wewnętrznego i spójność. Największe wartości kąta tarcia wewnętrznego uzyskano przy pielęgnacji powietrznej, a najmniejsze przy pielęgnacji wodnej przy odwrotnej zależności dla spójności. Wzrost czasu pielęgnacji spowodował kilkukrotny wzrost spójności, przy niewielkich zmianach kąta tarcia wewnętrznego.

2

Liniowe prawa tarcia warstwy ziarna zbóż

84%

Molenda M. , Horabik J.

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tom R. 6, nr 6

149--156

PL

Analizowano czynniki wpływające na tarcie ziarna zbóż. Stwierdzono, że zawartość wody, poziom naporu normalnego i procedura konsolidacji próbki wpływają istotnie na wyniki pomiaru współczynnika tarcia. Zależności naporu stycznego od naporu normalnego modelowano przebiegami liniowymi. Stwierdzono, że w zakresie zawartości wody 0,11-0,25 kg/kg i w zakresie naporu 20-100 kPa model liniowy bez wyrazu wolnego wystarczająco dokładnie opisuje tarcie ziarna pszenicy.

EN

Some factors affecting the friction of cereal grain were considered. Grain moisture content, the level of normal pressure and the procedure of sample consolidation were found to influence significantly the results of measuring friction coefficient. Linear relationship between frictional load and normal load were fitted to experimental results. The linear model without any free term was found to describe adequately the friction of wheat grain at the moisture content (dry basis) ranging from 0.11 to 0.25 kg/kg and the pressure range within 20-100 kPa.

3

Study of bearing capacity of skirted irregular pentagonal footings on different sands

84%

Thakur A. , Dutta R. K.

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tom Vol. 105, nr 1

5--17

EN

Purpose: The paper presents an experimental and numerical study to evaluate the bearing capacity of unskirted, singly and doubly skirted irregular pentagonal footings on different sands (S1, S2, S3) at a relative density of 30 %. The skirt depth of the footing was varied from 0.0B to 1.5B (B is the width of the square footing). Design/methodology/approach: The experimental and numerical study of the singly and doubly skirted irregular pentagonal footing resting on sands was modelled in a test tank and Plaxis 3D software respectively. Findings: The results of this study reveal that the bearing capacity was higher for the skirted irregular pentagonal footings on sand S3 followed by sand S2 and S1. The lowest percentage improvement for the singly skirted footing on sand S3 was 18.51% at a Ds/B = 0.25 whereas the highest improvement was 90.81% at a Ds/B = 1.50 for the singly skirted footing on sand S2. The highest percentage improvement for the doubly skirted footing on sand S2 was 95.13% at a Ds/B = 1.5 whereas the lowest improvement was 23.70% at a Ds/B = 0.25 the doubly skirted footing on sand S3. The results further revealed that the numerically obtained bearing capacity was marginally higher in comparison to the one obtained experimentally for the footings on all sands. Further, the experimental results validated the results obtained numerically with an average deviation of 8%. The percentage improvement in the bearing capacity was higher for the irregular pentagonal footing resting on sand S2 in comparison to sand S3 and S1. The settlement response of the irregular pentagonal footings is unchanged by increasing the number of elements beyond 7700. Both the experimental and numerical studies revealed a linear elastic behaviour at Ds = 0.5B, while the experimentally obtained pressure-settlement ratio plot shows a clear failure at Ds= 1B and 1.5B. Research limitations/implications: The results presented in this paper were based on the experimental and numerical study conducted on small scale model footings. However, for the actual footings, further study is recommended using full-scale field size footings to generalize the results. Originality/value: No experimental and numerical studies on singly and doubly skirted irregular pentagonal footings were conducted so far. Hence, an attempt was made in this article to predict the bearing capacity of these footings experimentally and using Plaxis 3D respectively.