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Contribution to the a priori assessment of the value of the caving zone expansion coefficient in the forecast of ground surface uplift caused by the flooding of closed coal mines in the Ruhr region/Germany

Rafał Misa, Mateusz Dudek, Anton Sroka, Krzysztof Tajduś, Dawid Mrocheń

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2024

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Vol. 72, nr 2

art. no. e148611

EN

The article presents a methodology for determining the value of the expansion coefficient of a reconsolidated caving zone in the context of forecasting the rise in underground mine water levels and consequent surface subsidence caused by the process of flooding the closed coal mines. The paper also provides a brief characterisation of analytical predictive models regarding surface subsidence during the process of flooding coal mines. In order to describe the vertical deformation of the reconsolidated porous rock mass in the caving zone, a linear-elastic medium of Biot was utilised. The conducted theoretical calculations demonstrate a high agreement with the results obtained through the identification of the expansion coefficient parameter based on the analysis of in-situ subsidence measurements in Dutch and German mining areas. The proposed methodology was applied to a real case study involving the forecasting of the impact of the flooding process on the underground workings of the German Ibbenbüren mine. The article constitutes a significant contribution to the field of forecasting the rise in underground mine water levels and surface subsidence during the process of flooding closed coal mines. The presented methodology and obtained results can be valuable for researchers, engineers, and decision-makers involved in the planning and management of mining areas.

2

Effect of the entire coal basin flooding on the land surface deformation

Tajduś Krzysztof, Sroka Anton, Dudek Mateusz, Misa Rafał, Hager Stefan, Rusek Janusz

Archives of Mining Sciences

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2023

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Vol. 68, no. 3

375--392

EN

This paper presents one of the environmental problems occurring during underground mine closures: according to the underground coal mine closure programme in Germany, the behaviour of the land surface caused by flooding of the entire planned mining area – the Ruhr District – had to be addressed. It was highlighted that water drainage would need to be continuous; otherwise, water levels would rise again in the mining areas, resulting in flooding of currently highly urbanised zones. Based on the variant analysis, it was concluded that the expected uniform ground movements caused by the planned rise in the mining water levels (comprising a part of two concepts – flooding up to the level of –500 m a.s.l. and −600 m a.s.l.), in the RAG Aktiengesellschaft mines, will not result in new mining damage to traditional buildings. The analysis included calculations of the maximum land surface uplift and the most unfavourable deformation factor values on the land surface, important from the point of view of buildings and structures: tilt T, compressive strain ε– and tensile strain ε+. The impact of flooding on potential, discontinuous land surface deformation was also analysed.

3

Numerical Modeling of the Pipeline Uplift Mechanism in Clay

Abdelfateh Kattar, Mohamed Baheddi, Fattah Mohammed Yousif

Archives of Hydro-Engineering and Environmental Mechanics

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2021

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Vol. 68, nr 2

119--135

EN

Buried pipelines are a vital infrastructure and are mainly used to transport energy carriers and other essential products. The pipes are generally buried in the upper layer of soil deposits and, therefore, are highly affected by different geo-environmental conditions. The various pathological cases recorded in the world are caused by the degradation of structures in contact with swelling soils, the fact that necessitates a full understanding and investigation of such a phenomenon. This paper presents a method for the pipeline behavior modeling based on the finite element analysis by using PLAXIS 3D software, aimed at the determination of the pipe bending moment, displacement over its length, and the evaluation of vertical stresses in soil under the pipe. A parametric study has been carried out to investigate the effect of the pipe burial depth and the soil cohesion. The finite-element results have been compared with experimental data from the literature. It was found that, unlike laboratory models, the numerical analysis can account for the internal pressure in the pipe and the depth of the pipe burial. The finite-element analysis showed that the presence of fluid pressure inside the pipe results in a decrease in the maximum swelling of the soil by about 95%. The displacement of the pipe is considerably affected by the burial depth. The vertical stress at one end of the pipe can be greater than that at the other end in the case of a pipe under internal pressure, while in the case of an empty pipe, the values are very close at both ends. The numerical analysis shows that an increase in the pipe internal pressure leads to a decrease in its vertical displacement.

4

Analysis of steel industrial portal frame building subjected to loads resulting from land surface uplift following the closure of underground mines

Dudek Mateusz, Rusek Janusz, Tajduś Krzysztof, Słowik Leszek

Archives of Civil Engineering

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2021

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Vol. 67, nr 3

283--298

EN

The liquidation of underground mines by the flooding leads to movements of the rock mass and land surface as a result of pressure changes in the flooded zones. The changes resulting from the rising water table caused by the changes in the stress and strain state, as well as the physical and mechanical properties of rock layers, can lead to damage to building structures and environmental changes, such as chemical pollution of the surface water. For this reason, the ability to predict the movements of rock masses generated as a result of mine closure by flooding serves a key function in relation to the protection of the land surface and buildings present thereon. This paper presents an analysis of a steel industrial portal-frame structure under loading generated by the liquidation of a mine by flooding. The authors obtained land surface uplift results for the liquidated mine and used them in a numerical simulation for the example building. Calculations were performed for different cases, and the results were compared to determine whether limit states may be exceeded. A comparison was made between the cases for the design state and for additional loading caused by the uplift of the subsurface layer of the rock mass.

PL

Likwidacja podziemnych kopalń przez zatapianie prowadzi do ruchów górotworu i powierzchni terenu w wyniku zmian ciśnienia w strefach zatapianych. Zmiany wynikające z podniesienia się zwierciadła wody podziemnej, spowodowane zmianami stanu naprężenia i odkształcenia oraz właściwości fizycznych i mechanicznych warstw skał mogą prowadzić do uszkodzeń powierzchniowych obiektów budowlanych oraz zmian środowiskowych, takich jak chemiczne zanieczyszczenie wód przypowierzchniowych. Z tego względu możliwość przewidywania ruchów górotworu powstających w wyniku likwidacji kopalń przez zatapianie pełni kluczową funkcję w odniesieniu do ochrony powierzchni terenu i znajdujących się na nim budynków. W artykule przedstawiono analizę przemysłowej stalowej hali magazynowej pod obciążeniem wynikającym z likwidacji kopalni w wyniku jej zatapiania. Autorzy uzyskali wyniki wypiętrzenia terenu zlikwidowanej kopalni i wykorzystali je w symulacji numerycznej przykładowego budynku. Obliczenia przeprowadzono dla różnych przypadków, a wyniki porównano w celu określenia, czy możliwe jest przekroczenie stanów granicznych. Dokonano porównania pomiędzy stanem projektowym i dla dodatkowego obciążenia spowodowanego wypiętrzeniem przypowierzchniowej warstwy gruntu.

5

Co-seismic and post-seismic deformation, field observations and fault model of the 30 October 2020 Mw = 7.0 Samos earthquake, Aegean Sea

Ganas Athanassios, Elias Panagiotis, Briole Pierre, Valkaniotis Sotiris, Escartin Javier, Tsironi Varvara, Karasante Ilektra, Kosma Chrysanthi

Acta Geophysica

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2021

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Vol. 69, no. 3

999--1024

EN

On 30 October 2020, a large Mw = 7.0 earthquake occurred north of the island of Samos, Greece. Here we present the characteristics of the seismic fault (location, geometry, geodetic moment) as inferred from the processing of geodetic data (InSAR and GNSS). We use the InSAR displacement data from Sentinel-1 interferograms (ascending orbit 29 and descending 36) and the GNSS offsets from fourteen (14) stations in Greece and Turkey to invert for the fault parameters. Our inversion modelling indicates the activation of a normal fault offshore Samos with a length of 40 km, width of 15 km, average slip of 1.7 m, a moderate dip-angle (37°) and with a dip-direction towards North. The inferred fault is located immediately north of, and adjacent to Samos with the top of the slip ~ 0.6 km below surface, and ~ 1 km offshore at its closest to the island. Near the fault, the earthquake caused the permanent uplift of the island up to 10 cm with the exception of a coastal strip along part of the northern shore that subsided 2–6 cm. The co-seismic horizontal motion of GNSS station SAMO was 35.6 cm towards south and 3 cm towards west. A post-seismic signal (22–33% of the co-seismic on the vertical component) was observed at GNSS stations SAMO and SAMU, with a time constant of 30 days. The effects of the earthquake included liquefaction, rock falls, rock slides, road cracks and deep-seated landslides, all due to the strong ground motion and associated down-slope mobilization of soil cover and loose sediments.

6

Mikrodeformacje filtracyjne gruntów

Dąbska Agnieszka, Popielski Paweł

Gospodarka Wodna

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2020

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Nr 2

15--18

PL

Przedstawiono przegląd makrodeformacji gruntu powstających w wyniku wyporu hydrostatycznego i filtracji. Omówiono różne zjawiska objęte ogólną nazwą makrodeformacji filtracyjnych gruntu: kurzawka (upłynnienie), przebicie hydrauliczne oraz wyparcie występujące w gruntach spoistych i niespoistych.

EN

The article presents a review of macro-deformations of soils originating as a result of water pressure head and filtration. It discusses different phenomena referred to commonly as filtrational macro-deformations of soils: hydraulic heave, piping and uplift in cohesive and non-cohesive soils.

7

O problemach w modelowaniu deformacji powierzchni terenu w aspekcie budownictwa na terenach górniczych

Paleczek W.

Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo

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2018

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Z. 24 (174)

267-272

PL

Przedstawiono rozwiązanie zadania modelowania obniżeń powierzchni terenu i górotworu, w którym uwzględniono jednoczesne występowanie: wstępnych przemieszczeń pionowych, asymetryzacji i wypiętrzeń. Podane wzory obliczeniowe opracowano na podstawie studium teoretyczno-empirycznego. Mogą być one przydatne do celów inżynierskich i konstrukcyjnych przy zastosowaniu w modelowaniu konstrukcji i budownictwie na terenach wpływów podziemnej eksploatacji górniczej.

EN

The paper presents a solution to the problem of modeling the depressions of terrain and rock mass, in which simultaneous occurrence of: initial vertical displacement, asymmetrization and elevation was taken into account. The calculation formulas given have been developed on the basis of a theoretical and empirical study. They can be useful for engineering and construction purposes when used in modeling structures and construction in the areas of underground mining exploitation.

8

Optical dating of sediments from manas lake in northwestern china: Paleoenvironmental and neotectonic implications

Tse Y.-Y., Li S.-H.

Geochronometria

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2017

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Vol. 44, no. 1

175--187

EN

Manas Lake is a closed lake basin in northern Xinjiang Province of China, with its current lake bed at 244 m a.s.l. Sediments from the lake area provide valuable information about the paleoenvironmental changes in the Westerlies-dominated arid region. To obtain a chronological constraint on the past changes, optically stimulated luminescence dating was conducted on sediments from the lake beaches. The results show that lacustrine episodes dated at ~80–73 ka ago were recorded in northwestern side of the lake at 270 m a.s.l., while paleoshoreline to near-shore environments during ~80–90 ka ago were recorded in the opposite side of the lake at 262 m a.s.l. The ~80 ka old sedimentary layers are overlain by paleoshoreline sediments formed within the last ~1 ka, separated by a large age gap. From this study and the results from previous studies, it is concluded that breaks in sedimentary records are common in the lake area at elevation > 260 m a.s.l. When comparing sedimentary environments at different times from different sites in this study and previous studies, it is suggested that a small amount of uplift of the northwestern side of Manas Lake relative to the southeastern side may have occurred in the last 80 ka.