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

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

Forecast of rock mass and ground surface movements caused by the convergence of salt caverns for storage of liquid and gaseous energy carriers: Forecast of rock mass and ground surface movements caused by the convergence of salt caverns for storage of liquid and gaseous energy carriers

The paper presents a method of calculating deformation coefficients for any point situated in the overlying rock mass or on the ground surface. This solution was based on the method presented by Sroka and Schober (1982, 1987), taking into account new theoretical achievements and the current results of in situ measurements

Assessment of the behaviour of flysch rock mass during tunnel boring in the primary lining using indicators and limit values of displacements and deformations

The article describes the behaviour of the flysch rock massif (Carpathian flysch) during the drilling of three tunnels in the preliminary lining. These tunnels were excavated in: “Naprawa”, “Laliki”, and “Świnna Poręba”. The distance between these tunnels in a straight line was 50 km to 90 km. The results of the displacement of the contours of these tunnels and their convergence were analysed in detail. These values were compared with the indices used to assess the behaviour of the rock mass in the tunnel environment (Zasławski index and Hoek index) and the adopted limit values of displacements and deformations. On this basis, a critical analysis of the selection of initial supports in the completed tunnels was made, showing errors at the design stage

Some Considerations on Horizontal Displacement and Horizontal Displacement Coefficient B

Mining-induced deformations of the ground surface and within the rock mass may pose danger not only for surface constructions but also for underground objects (e.g., tunnels, underground storages, garages), diverse types of pipelines, electric cables, etc. For a proper evaluation of hazard for surface and underground objects, such parameters as horizontal displacement and horizontal deformations, especially their maximum values, are of crucial importance. The paper is an attempt at a critical review of hitherto accomplished studies and state of the art of predicting horizontal displacement u, in particular the coefficient B, whose value allows determination of the value of maximum displacement if the value of maximum slope is known, or the value of maximum deformation if the value of maximum trough slope is recognized. Since the geodesic observations of fully developed subsidence troughs suggest that the value of the coefficient depends on the depth H, radius of main influences range r and properties of overburden rock, in particular the occurrence of sub-eras Paleogene and Neogene layers (old name: Quaternary and Tertiary) with low strength parameters, therefore a formula is provided in the present paper allowing for the estimation of the influence of those factors on the value of coefficient B

Numerical Modelling of the Mining Induced Horizontal Displacement

The paper presents results of numerical calculations and modeling of mining-induced surface deformation based on Finite Element Method (FEM). Applying the numerical method discussed to calculations allows us to assume a larger number of factors, such as rock mass structure, fracture network, rock properties, etc., which essentially affect the results obtained. On the basis of an elastic transversely isotropic model, an analysis of horizontal displacement distribution and surface subsidence was carried out for two sample regions of mines. The results of numerical calculations were later compared with the measured values. Such an analysis proved that the applied numerical model properly described distribution and values of subsidence and slope of subsidence trough, though there were serious differences in the values of calculated horizontal displacement, especially in areas of far influence range. In order to improve the matching, the influence of boundary conditions of the model on the value of calculated horizontal displacement was analyzed. The results are presented in graphs

Analysis of Mining-Induced Delayed Surface Subsidence

The topic of residual subsidence is important in Europe as it defines possible surface deformation for closed mine areas. It has to be determined because of potential financial claims and damages of sensitive objects such as satellite dishes, precision mechanics objects, agriculture, forestry and hydrogeology, etc. Analyses of measured subsidence after the end of mining exploitation indicate that this process can last from several months to several dozen or even several hundred years, and the final surface subsidence is not known. It is dependent on the individual’s features of excavated medium, depth of exploitation, a system of exploitation, behaviour of surrounding rock masses, etc. In the article, the authors analysed the assessment of the subsidence process after the end of mining operations, based on the innovative method. This concerns the duration of the subsidence process and the size of the expected subsidence. The methodology was applied to the RAG Aktiengesellschaft company project where prognostic calculations were made for seven closed coal mines using unique results of precise height measurements carried out for more than 90 years by the German State Office for National Measurements (Landesvermessungsamt NRW) under the so-called levelling measurements net. These measurements are carried out every 2 years and serve to keep the altitude network in the whole state of Rhineland Westphalia up-to-date. The result of the prognosis for one case study, German mine Auguste-Victoria, is presented in the article

The influence of normal fault on initial state of stress in rock mass

Determination of original state of stress in rock mass is a very difficult task for rock mechanics. Yet, original state of stress in rock mass has fundamental influence on secondary state of stress, which occurs in the vicinity of mining headings. This, in turn, is the cause of the occurrence of a number of mining hazards, i.e., seismic events, rock bursts, gas and rock outbursts, falls of roof. From experience, it is known that original state of stress depends a lot on tectonic disturbances, i.e., faults and folds. In the area of faults, a great number of seismic events occur, often of high energies. These seismic events, in many cases, are the cause of rock bursts and damage to the constructions located inside the rock mass and on the surface of the ground. To estimate the influence of fault existence on the disturbance of original state of stress in rock mass, numerical calculations were done by means of Finite Element Method. In the calculations, it was tried to determine the influence of different factors on state of stress, which occurs in the vicinity of a normal fault, i.e., the influence of normal fault inclination, deformability of rock mass, values of friction coefficient on the fault contact. Critical value of friction coefficient was also determined, when mutual dislocation of rock mass part separated by a fault is impossible. The obtained results enabled formulation of a number of conclusions, which are important in the context of seismic events and rock bursts in the area of faults

Określanie wartości parametrów odkształceniowych górotworu uwarstwionego w rejonie wpływów eksploatacji górniczej praca doktorska /

Tyt. z ekranu tytułowego.Praca doktorska. Akademia Górniczo-Hutnicza im. Stanisława Staszica (Kraków), 2008.Zawiera bibliogr.Dostępna także w wersji drukowanej.Tryb dostępu: Internet.Zachowanie się górotworu w rejonie eksploatacji ścianowej z zawałem stropu, ogólne hipotezy opisujące zachowanie się górotworu w rejonie eksploatacji, powstawanie stref zawału, stref spękań w wyniku przejścia podziemnej eksploatacji, strefa zasięgu wpływów górniczych, teoria Knothego, wpływ wybranych czynników geometrycznych na wartość deformacji powierzchni, wpływ kształtu, wysokości strefy zawału całkowitego, wpływ wysokości strefy spękań i własności skał w strefach zawału, spękań na przemieszczenia powierzchni terenu, wpływ kształtu zasięgu wpływów głównych na przemieszczenia powierzchni terenu, wpływ budowy warstwowej górotworu na przemieszczenia powierzchni terenu, dobór modelu numerycznego dla modelowania stanu naprężenia i przemieszczenia w rejonie eksploatacji ścianowej, rodzaje modeli fizycznych wykorzystywanych do opisu zachowania się górotworu w rejonie oddziaływania eksploatacji górniczej, charakterystyka skał występujących w strefie zawału lub spękań, model fizyczny, dobór założeń geometrycznych, fizycznych dla modelu, propozycja postępowania przy doborze parametrów odkształceniowych górotworu po przejściu eksploatacji, wybór klasyfikacji górotworu dla określenia parametrów odkształceniowych warstw skalnych, krótka charakterystyka poszczególnych klasyfikacji, klasyfikacja Terzaghiego, Deere, RQD, Wickhama, RSR, Bieniawskiego, RMR, Bartona, Lien’a, Lunde’ego, Q, Hoek’a, GSI, Palmstroma, RMI, wybór klasyfikacji geotechnicznej odpowiedniej dla wyznaczania parametrów górotworu polskich kopalń węgla, określenie parametrów odkształceniowych warstw skalnych dla wybranych poeksploatacyjnych rejonów kopalń, górotworu dla wybranego rejonu KWK „Bogdanka”, warunki górniczo-geologiczne w wybranym rejonie kopalni, określenie wartości parametrów teorii Knothego, model numeryczny MES, określenie parametrów odkształceniowych górotworu dla wybranego rejonu KWK „Siersza”, „Wieczorek”, "Marcel", „Wujek”, „Piast”, „Ziemowit”, „Budryk” „Wesoła”, „Staszic”, „Bielszowice”, określenie szacunkowej wartości parametru GSI klasyfikacji Hoek’a dla skał występujących w polskich kopalniach węgl

Wykorzystanie submodelingu do modelowania zachowania się budowli poddanej wpływom eksploatacji

Tyt. z nagłówka.Bibliografia s. 541.Dostępny również w formie drukowanej.STRESZCZENIE: Artykuł przedstawia analizę doboru odpowiednich warunków brzegowych dla modelowanego zjawiska wpływu eksploatacji podziemnej na budowlę. Autorzy skłonili się do próby rozwiązania tego problemu w sposób dwuczłonowy, wykorzystując model globalny i submodel. W technice zaproponowanej przez autorów warunki brzegowe zadawane na submodel stanowiły przemieszczenia pionowe i poziome wyliczone z modelu globalnego. Dodatkowo przeprowadzono analizę wpływu wielkości modelowanego podłoża, na stan naprężenia wewnątrz posadowionego na nim fundamentu. SŁOWA KLUCZOWE: MES, submodeling, model globalny, warunki brzegowe, górotwór, podłoże, budowla. ABSTRACT: This paper describes the correct selections of the bonduary conditions, of the models presents the influence of the underground excavations on the bulding based on FEM. The authors incline to solve this problem by using the dobblepart methods, based on global model and sub-model. In this technic the boundary conditions of the sub-model are the value of vertical and horizontal displacements calculate previously in global model. Aditionally the authors made some calculations of the influence of the size of the model bedrock of the stress values in the fundations based on it. KEYWORDS: FEM, submodelling, global model, boundary conditions, rock mass, subsoil