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1

Modeling the vibratory roller compaction process of road soils

Căpăţînă Dragoş, Niţu Marilena Cristina, Iliescu Mihaiela

Archives of Civil Engineering

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2023

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Vol. 69, nr 4

431--444

EN

Road infrastructure is aimed to be sustainable construction in today’s condition of heavy traffic. Depending on geotechnical characteristics of soils there are chosen adequate techniques for compaction, meaning: type of compaction, equipment, compaction parameters and, if possible, computer aided acquisition and processing of data. This paper presents research results on the vibratory roller compaction process of road soils, from the point of view of process mathematically modeling and statistically modeling of process parameters interdependence. The obtained regression model is innovative one and fit for further application in optimization (by AI and IoT) of the compaction process. Good correlation of all the results (self-pulsation values) proves the adequate assumptions for both modeling and experimenting. Further development of this research is intended to develop a special software for direct correlation of road geographical position and soil characteristics to the compaction process parameters optimum values.

2

Preliminary research of monitoring of soil density

Kwaśniewski Arkadiusz

Zeszyty Naukowe Instytutu Pojazdów / Politechnika Warszawska

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2019

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z. 3/121

31--39

EN

This work presents the preliminary method for assessment of the degree of the soil compaction from two types of research performed by the author. The first type of research was the tests with sensors placed directly on the rammers foot in the laboratory stand. The second stage of works was to perform test with the same stand and the machine with sensors placed on the measuring plate nearly the rammer. The results of test are processed and on the spectrum chart in the function of frequency are presented. This allow to show the differences between the loose and compacted soil. The difference type of mounting sensors has influence to vibroacoustic signal and on the frequency spectrum.

PL

W pracy została zaprezentowana wstępna metoda oceny stopnia zagęszczenia ośrodka gruntowego na podstawie dwóch typów badań wykonanych przez autora. Pierwszym typem były badania przy użyciu maszyny zagęszczającej grunt znajdujący się w stanowisku laboratoryjnym, z czujnikami zamocowanymi bezpośrednio do stopy maszyny. Drugim etapem prac było wykonanie testów przy użyciu tego samego stanowiska i maszyny z czujnikami umieszczonymi na płycie pomiarowej obok zagęszczarki. Obróbka uzyskanych wyników i przedstawienie ich na wykresach widma w funkcji częstotliwości, pozwoliło na ukazanie różnic pomiędzy ośrodkiem luźnym i zagęszczonym. Zostały zaprezentowane różnice pomiędzy typem umieszczenia czujników na sygnał wibroakustyczny, a także na samo widmo amplitudowo-częstotliwościowe.

3

Compaction of lignite: a review of methods and results

Widera M.

Acta Geologica Polonica

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2015

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Vol. 65, no. 3

367--378

EN

The published peat:coal compaction ratios range from 1.1:1 to 60:1 and from 1.1:1 to 11:1 for lignites. These probably represent realistic end-member values for the degree of compaction during the transformation of peat into lignite and then to coal. Hence, in many cases, the obtained values of the compaction ratio are under- or overestimated with reference to the entire coal seam. This study focuses on the changes of thickness between a peat bed and the resulting lignite seam. The fundamental question is how many times the thickness of the peat bed, prior to covering the mire by the overburden, was greater than the present-day thickness of the lignite seam. The majority of methods reported in this paper cannot be used directly to quantify the amount of compaction of the lignite seam. In this context, the only category of methods which allow a direct estimation of the peat:lignite compaction ratio are the so-called stratigraphic methods. Therefore, based on comparison of the initial peat bed thickness with lignite seam thickness, the most accurate peat:lignite compaction ratio ranges from 2:1 to 4:1.

4

Badania nowej konstrukcji formierki impulsowo-prasujacej

Izdebska-Szanda I., Leśniewski W., Pezarski F., Soliński W.

Archiwum Odlewnictwa

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2006

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R. 6, nr 18/2

483--488

PL

Wychodząc naprzeciw potrzebom krajowych odlewni, Instytut Odlewnictwa - Kraków i Dozamet – Nowa Sól opracowały nową konstrukcję formierki impulsowo-prasującej, przeznaczonej do wykonywania połówek form z mas bentonitowych w skrzynkach o wymiarach 1000 x 800 x 250 – 350 mm. Ideą nowej konstrukcji jest umieszczenie zespołu impulsowego i prasującego w jednej przestrzeni. W artykule przedstawiono wyniki prób i badań nowej konstrukcji formierki na stanowisku badawczym w Dozamet - Nowa Sól.

EN

To meet the requirements of the domestic foundries, Foundry Research Institute in Cracow and Dozamet – Nowa Sól offered a new design of the impulse-squeeze moulding machine assigned for manufacture of half moulds made from bentonite sands in flasks of 1000 x 800 x 250 – 350 mm dimensions. The crucial point of this new design is placing the impulse and squeeze assemblies within one single space. The paper gives the results of the tests and trials carried out on this new moulding machine on a pilot post operating at Dozamet - Nowa Sól.

5

Analiza wybranych aspektów formowania podciśnieniowego

Ślazyk M.

Archiwum Odlewnictwa

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2004

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R. 4, nr 11/2

257--262

PL

Oferta maszyn formierskich jest bardzo szeroka. Realizowane jest zwykle zagęszczanie wieloetapowe z wykorzystaniem doprasowania w ostatniej fazie formowania. Nowoczesne formierki umożliwiają zmianę parametrów pracy maszyny. Dobór optymalnych parametrów wymaga znajomości realizowanego procesu zagęszczania. W pracy przedstawiono warianty formowania podciśnieniowego z doprasowaniem oraz wybrane wyniki badan tej metody.

EN

Current offer of moulding machines are very wide. There are usually used two-step compaction process. The final compaction method is squeezing. Modern moulding machines give possibilities of operation parameters changing. The proper choice of operation parameters need serious knowledge about realised compaction process. In the paper the own research results and analysis of moulding method based on suction pre-compaction and squeezing. The selected moulding machines using this method of compactions have been described.

6

A yield criterion for powdered metal compaction

Chen F. K.

Applied Mechanics and Engineering

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1998

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Vol. 3, no 3

413-432

EN

A yield criterion and the associated flow rule for the powdered metal compaction was proposed in the present study. In the proposed yield criterion, both the bulk movement and the consolidation of powdered metal in the compaction process were considered. In order to reflect the effect of volume change in the powder deformation, the first invariant of the stress tensor was added in the proposed yield criterion. Some previous yield criteria suggested for bulk materials were also evaluated in the present study to investigate the possible yield locus for the powder compaction. Material constants were introduced in the proposed yield criterion and the experimental procedures for the determination of these material constants were established. The states of stress predicted by the proposed yield criterion for the deformation of powder in the compaction process were compared with those obtained from the triaxial compaction test. The good agreement between the predicted values and the experimental results confirms the validity of the proposed yield criterion.