The paper presents research results on the selection of parameters for the asymmetric rolling process of bimetallic plates 10CrMo9-10 + X2CrNiMo17-12-2. They consisted in determining the optimum parameters of the process, which would be ensured to obtain straight bands. Such deformation method introduces in the band the deformations resulting from shear stress, which affect changes in the microstructure. But their effect on the structure is more complicated than in the case of homogeneous materials. It has been shown that the introduction of asymmetric conditions into the rolling process results in greater grain refinement in the so-called hard layer. There was no negative effect on the structural changes in the soft layer observed.
Coal mining activities carried out for 200 years in Upper Silesia have had a negative effect on buildings. T his impact is in all cases related with continuous deformations of the surface and in certain cases with discontinuous deformations (mostly cave-ins), changes in water relations and mining tremors. T he paper presents an evaluation of the impact of a mining activity on a building situated in the Upper Silesian Coal Basin. T he building was affected by continuous deformations and mining tremors. Calculations were made of the values of deformation rates by means of Budryk–Knothe’s theory, which were partly verified on the basis of the results from geodetic measurements. An analysis of the velocity and acceleration of basement vibrations caused by mining-induced tremors was also conducted. T he conclusions included a high consistency between the results obtained on the basis of calculations and the values obtained by means of PGA and PGV measurements. In the case of tremors with the highest energy in the hipocentrum, there an empirical formula allowing for calculation of PGA value in given geological and mining conditions was also proposed. T he application range of the formula mentioned above is obviously limited only to the conditions in consideration. The presented conclusions indicate that at present, sufficiently precise methods, allowing for calculations for practical purposes, not only of deformation indices’ values, but also of PGV and PGA values, presently exist.
Currently available field rock mass deformability determination methods are rather difficult to perform, due to their complexity and a time-consuming nature. This article shows results of a suitability assessment of a Pen206 borehole jack (a hydraulic penetrometer) for field rock mass deformability measurements. This type of the borehole jack is widely used in Polish hard coal mining industry. It was originally intended only for quick rock mass strength parameters determination. This article describes an analysis and scope of basic modifications performed mainly on a borehole jack head. It includes discussion of results with possible directions for future development of the device.
Water is the main source of daily life for everyone and everywhere in the world. Sufficient water distribution depends on the place and design of water tank in certain areas. Water storage tanks are relatively flexible structures and they can tolerate greater settlements than other engineering structures. Deformation of tanks may cause severe damages to tank or even loss of life and injury to people, so monitoring the structural deformation and dynamic response of water tank and its supporting system to the large variety of external loadings has a great importance for maintaining tank safety and economical design of manmade structures. This paper presents an accurate geodetic observations technique to investigate the inclination of an elevated circular water tank and the deformation of its supporting structural system (supporting columns and circular horizontal beams) using reflector-less total station. The studied water tank was designed to deliver water to around 55000 person and has a storage capacity about 750 m3. Due to the studied water tank age, a non-uniform settlement of tank foundation and movement of pumps and electric machines under tank’s body will cause stress and strain for tanks membrane and settlement of sediments. So the studied water tank can tend to experience movement vertically, horizontally or both. Three epochs of observations were done (July 2014, September 2014 and December 2014). The results of the practical measurements, calculations and analysis of the interesting deformation of the studied elevated tanks and its supporting system using least squares theory and computer programs are presented. As a results of monitoring the water storage tank, circular reinforced concrete beams and columns at three monitoring epochs. The body of water storage tank has an inclination to the east direction and the value of inclination is increased with the time.
Underground mining extraction causes the displacement and changes of stress fields in the surrounding rock mass. The determination of the changes is extremely important when the mining activity takes place in the proximity of post-flotation tailing ponds, which may affect the stability of the tailing dams. The deterministic modeling based on principles of continuum mechanics with the use of numerical methods, e.g. finite element method (FEM) should be used in all problems of predicting rock mass displacements and changes of stress field, particularly in cases of complex geology and complex mining methods. The accuracy of FEM solutions depends mainly on the quality of geomechanical parameters of the geological strata. The parameters, e.g. young modulus of elasticity, may require verification through a comparison with measured surface deformations using geodetic methods. This paper presents application of FEM in predicting effects of underground mining on the surface displacements in the area of the KGHM safety pillar of the tailing pond of the OUOW Żelazny Most. The area has been affected by room and pillar mining with roof bending in the years 2008-2016 and will be further exposed to room-and-pillar extraction with hydraulic filling in the years 2017–2019.
Hydrocarbon production under certain geological conditions of these deposits can cause surface subsidence and deformation of the terrain surface. Such deformations appear as subsidence troughs of considerable range and the magnitude of the subsidence depending on the total thickness of the reservoir, compaction properties of reservoir and on the number of other factors. In the past there have been widely recognized magnitudes of the subsidence up to 9 meters. The stress zones in the subsidence trough may affect the buildings and surface structures. However there have been well known some cases of destroyed boreholes or pipelines belonging to the gas or oil mine. Therefore there is a requirement to analyze the possibility of occurrence unfavorable phenomenon on the ground surface, to monitor surface deformations during production and to protect surface infrastructure located in the range of mining influences. In the paper the issue of surface subsidence caused by hydrocarbon production has been presented. The cause - effect relationship between the compaction of thereservoir rock and the subsidence of surface area has been assumed. The prediction model base on the influence function and on the superposition of elementary influences. For the purpose of building damage protection a new model of risk assessment has been developed. This model base on the elements of fuzzy logicallows to incorporate in the analysis the quantitative and qualitative factors that contribute to the risk of building damage. Use of the fuzzy logic made it possible to obtain one value which clearly discriminate the risk of buildings damage. However, risk analyzes of damage to the large number of buildings has been required additional tools. The spatial analysis has been made by using GIS. The subjects of the paper have been illustrated with a practical example.
The article is focused on the most recent investigations of glaciotectonic structures in high escarpment exposures of the Vistula valley from Dobrzyń to Kuzki in the western part of the Płock Basin. Deformations involve Neogene and occasionally the Lower Pleistocene deposits and they are not expressed as landforms. Structural investigations and analysis of archival geological data provided new information on the origin of large-scale shear structures. Results obtained are clearly contrary to the concept of Brykczyński (1982) regarding valley-side glaciotectonics in the Płock Basin. An emergence of the extensive zone of serial thrust structures of significant amplitude (up to 100–150 m) was found to have not been controlled by a palaeovalley. A driving mechanism is interpreted as a gravity spreading in front of ice sheets advancing from north-northeast during the South Polish Complex (Dorst-Elsterian).
This study was undertaken to investigate the effect of severe plastic deformation (SPD) by extrusion combined with reversible torsion (KoBo) method on microstructure and mechanical properties of Al-5Cu and Al-25Cu alloys. The extrusion combined with reversible torsion was carried out using reduction coefficient of λ = 30 and λ = 98. In this work, the microstructure was characterized by light microscopy (LM), scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM). Compression test and tensile test were performed for deformed alloys. The binary Al-5Cu and Al-25Cu alloys consist of the face cantered cubic (FCC) α phase in the form of dendrites and tetragonal (C16) θ-Al2Cu intermetallic phase observed in interdentritic regions. The increase of Cu content leads to increase of interdentritic regions. The microstructure of the alloys is refined after applying KoB deformation with λ = 30 and λ = 98. Ultimate Tensile Strength (UTS) of Al-5Cu alloy after KoBo deformation with λ = 30 and λ = 98 reached about 200 MPa. UTS for samples of Al-25Cu with λ = 30 and λ = 98 increased compared to Al-5Cu alloy and exceed 320 MPa and 270 MPa respectively. All samples showed increase of plasticity with increase of reduction coefficient. Independently of reduction coefficient, the compressive strain of Al-5Cu alloys is about 60%. The Al-25Cu alloy with λ = 98 showed the value of compressive strain exceed 60%, although for this same alloy but with λ = 30, the compressive strain is only 35%.
The paper presents the effect of deformation temperature on the mechanical stability of retained austenite in a multiphase TRIP steel. Series of static tensile tests were carried out in the temperature range –20 to 140°C in order to simulate the temperatures occurring during stamping process of automotive steel sheets and conditions of their exploitation. Samples deformed at 20°C and 60°C showed the best combination of strength and ductility. It was related to the gradual transformation of retained austenite into martensite. Obtained results revealed that the intensity of TRIP effect is significantly related to the deformation temperature. The amount of retained austenite, which transformed into martensite during plastic deformation decreases as the deformation temperature increases. It was also found that the stability of retained austenite depends on its morphology. The obtained results showed the relationship between deformation temperature and the stability of retained austenite. The chemical composition and microstructure of multiphase steels dedicated to the automotive industry should be designed for providing the maximum TRIP effect at the specific deformation temperatures.