Karel Kubečka

Deformation of slopes as a cause of underground mining activities: three case studies from Ostrava–Karviná coal field (Czech Republic)

Underground mining activities may potentially play a role on the initiation and reactivation of the slope movements. However, an adequate attention has not yet been paid to these problems; in this study, the possible influence of present and former mining activities on the selected set of model slope deformations in the Ostrava–Karviná Coalfield (Opliji, Repiste and Orlova Lazy District) was analysed and a methodology for their observation for application to similar conditions and influence was described. Isocatabase maps, terrain deformation parameters calculated for the point lying on the slope deformation surface, length measurement by zone extensometer and dilatometer measurement in cracks was also provided for evaluation of the underground mining impact. It was found that inclinations of both boreholes were evidence of underground mining impact, and localization of inclinometer measurement on boreholes in the active part as well as in the near vicinity was very important as an important result of this study. Analysis of underground mining activity influence on model localities in relation to performed mining operations, subsidence and other influences on the ground surface was also determined. Thus, the study will contribute to a more objective knowledge of these problems of interest for the professional public and also for the state administration to solve problems associated with the utilisation and settlement of such affected areas.

Subsidence map of underground mining influence for urban planning: an example from the Czech Republic

The objective of this study is to produce a subsidence map linked to underground mining influence in a mining region. Ground subsidence represents the most important characteristic of a subsidence basin. However, ground subsidence itself does not carry information on geohazards by means of the impacts on the built-up area. Based on long-term experience and studies carried out, three basic subsidence intervals of varying influence were proposed. The lowest degree of undermining influence is connected with subsidence up to 12 cm; the second category is for subsidence from 12 to 100 cm, where constructions are considered possible under certain conditions but special technological procedures must be adhered to; and the third category of hazard is for subsidence over 100 cm. The study was implemented in the largest mining region (black coal deep mining) of the Czech Republic, in the locality of Orlova, Petrvald and Karvina. The study also involved an overall evaluation of subsidence influence, its variation with time, its relation to the current built-up area and to the future built-up area according to the land use plan, and its relation to engineering-geological zones and landslides.

Utilization of ground subsidence caused by underground mining to produce a map of possible land-use areas for urban planning purposes

The presented work deals with a new type of map titled—a map of a possible area use for planned built-up area purposes in areas affected by underground mining-related subsidence. Generally, accepted theory of a subsidence basin must be applied to such areas, and in order to produce the map, ground subsidence isolines, land-use plan, and slope deformation distribution were considered. The map can be used by land-use planners, future developers, investors, engineering geologists, etc. to inform future development of such land. It is clear that land-use planners may not have sufficient knowledge to decide whether the ground subsidence value is acceptable or not for a particular development purpose. At the same time, it shows that the existence of slope deformations also influences the siting of new buildings in undermined areas and therefore these were included in the map compilation process. The outcome is three area categories where mining subsidence impacts surface development, namely—low influence on the planned development, economically acceptable influence on the planned development, and extreme influence with development prohibited. The research was carried out in the Darkov Region in the northeast of the Czech Republic, where black coal is mined and extensive mining impact on the surface identified. The map produced in this study will help the controlled development of the region by means of appropriate land-use planning.

Application of the Engineering-Geological Conditions in Land-Use Plans in the Petrvald Region Czech Republic

The objective of this paper is to demonstrate necessity to inform relevant parties about engineering-geological conditions for various practical purposes, especially including appropriate land-use planning. However, the relationship between relevant geological information and the geological environment is vital for foundation engineering purposes, especially where demanding structures are involved. This information is most conveniently structured when accumulated information concerning engineering-geological zones is utilized. This necessarily includes knowledge of rock workability and also of the pre-Quaternary bedrock, and these characteristics were then related to the current built-up area and future development according to the land-use plans in a case study are from the Petrvald Region (Czech Republic). The geological environment of area has been severely influenced by anthropogenic effects of deep black coal mining. Results of this research showed that future development should be founded on spoil banks, dumps, and settling basins. According to the land-use plan, this zone occupies 44.9% of the area of interest, and its materials predominantly emanate from mining in the Ostrava–Karvina Coal District. For future foundation structures planned there, it is imperative to consult detailed engineering-geological study. However, attention to and reliance on this necessity is not reflected in the existing land-use plan.

Relevance of building site categories implementation into the land use plan in underground mining area in the region of Petrvald (Czech Republic)

Deep mining of mineral resources causes extensive changes in rock environment and ground morphology and must be considered in the land use planning. Subsidence as a result of underground mining activities in terrains is one of the serious geological hazards because they can effect slopes and damage engineering structures, settlement areas, natural lakes and allow infiltration of contaminant into the groundwater. The main aim of this article was implementation of the building site categories of underground mining regions into the land use plans. This case study area was selected from the region of Orlova town within the Ostrava-Karvina Coal district, and this region is one of the most affected areas by underground mining of black coal in the Czech Republic. Certain risk categories of land, where the individual categories express generalized influence of deep mining of coal in current and planned constructions were also represented in this article. Extensive variations caused by underground mining were identified within a wide variability of risk categories. An important finding was also the extensive variability over time, manifested by spatial variations in the stated categories in the studied time periods. Moreover, technical documentation of environmental impacts related to underground mining activities was provided; importance of existing and proposed underground mining projects that may significantly impact the land use was discussed and pointed out in this article, especially.

Utilization of an underground mining evaluation map incorporating the effect of landslides and surface flooding for land-use purpose

A number of problems related to land use and foundations of new structures are encountered in underground mining areas. Potential suitability and/or unsuitability of lands for new structures must be considered in areas affected by underground mining. It is well-known that subsidence, slope instability, and surface flooding are frequently observed in underground mining areas. Thus, a map that takes into account such geo-hazards and classifies suitable and unsuitable areas for new structures is needed. Areas affected by underground mining of coal in Stonava near to the border of the Czech Republic and Poland represent specific areas where subsidence, slope instability, and surface flooding problems need a strategy for future utilization of the landscape by means of land use plans. In light of the above reasons, the methodology and preparation of a map model incorporating the effect of landslides and surface flooding has been introduced in this study. This map depicts three levels of influence (important influence, moderate influence, and negligible influence). Chronological variations in the building site categories in the study area have been analyzed as another part of the study. It was further crucial to consider the current built-up area in the underground mining area, and therefore, its relation to building site categories has also been evaluated. Consequently, the building site categories were evaluated in relation to the planned built-up area, which is the most important landscape element in a land-use plan as a tool in the decision-making process.

Risk Assessment of Airtightness of Building Envelope

The paper deals with risk analysis of insufficient airtightness of the envelope construction. The risk analysis is a systematic and structured data processing to identify potential hazards. The main aim of paper is to qualified risks which arise from the danger, i.e. insufficiently airtight of the building envelope. The quality of airtight building envelope except for low energy consumption also minimizes the risk of damage to the structure associated with the spread of the heat, water vapor in the structure and fungal growth. The qualification of risks consists of choice of method and determinative indicators, input data and simulation of model with drawing results.

COMPARISON OF VARIOUS TYPES OF APPROACHES TO THE MINEABILITY OF ROCK

Mineability of rock is one of the most important characteristics of rocks in the field of engineering geology and geotechnical engineering. Mineability of rock is the amount of work that we need to expend to breakage resistance of rock, handling and loading rocks at surface earthworks. This characteristic is quantified using degrees of excavation difficulty. There are various classification systems with different span of individual classes. This property is the basis for the assessment of the financial costs of earthworks and it is one of the most important qualities for the economy of construction works. The aim of this publication is to make comparisons these systems.

Calculation and Reliability Assessment of Timber Structure Bolt Connection Subjected to Double Unequal Shears

The paper shows the calculation and reliability assessment of bolted connections subjected to unequal double shear with thin plates as outer members and inner timber member. The concrete example is calculated and explained.

Reliability of Timber Structure Bolt Connection Subjected to Double Unequal Shears

The paper deals with reliability in ultimate limit state of timber structure bolted connections subjected to unequal double shear with thin plates as outer members and inner timber member. There are derived equations for calculation of the reliability of this connection type in the ultimate limit state.