David Lamich

Unique documentation, analysis of origin and development of an undrained depression in a subsidence basin caused by underground coal mining (Kozinec, Czech Republic)

Abstract This article aims to explain and demonstrate the origin and development of a subsidence basin caused by coal mining as well as to point out important aspects of this phenomenon in engineering geology. Engineering geology needs to deal with a number of issues related to the origin and development of subsidence basins in areas affected by deep coal mining. An interesting case study from the Upper-Silesian Basin in the northeast of the Czech Republic near the Polish border is presented in this paper. There is a clear time chronological succession in the ground surface changes manifested by a ground subsidence gradation, both in their absolute values as well as in their spatial distribution. The phenomenon is documented by aerial photo time series, which optimally depict the origin and development of the subsidence. In the study area, there are changes in the landscape elements and it is essential to be considered in future land use plans. The marginal conditions of the Quaternary geological structure and hydrogeological conditions are responsible for an unconfined aquifer which manifests there as a water body in an undrained depression in the course of the ground subsidence.

Underground mining hazard map including building site categories in an area affected by underground mining activities

The objective of the paper is generation of an underground mining hazard map. The method applied to create the map is based on five categories of areas with different characters of underground mining influence making use of the so-called building site categories. The individual areas with different groups represent various suitability or unsuitability for founding new structures in such influenced territories. They will also reflect a higher or lower degree of influence on already existing structures. Areas affected by underground mining of category V are suitable without any significant restrictions. Areas of the medium category represent influence of building site categories III and IV with economically acceptable measures for founding engineering purposes. The last type is areas with high influence in the category I and II and they are clearly unsuitable for new development. Structures may be founded there in exceptional cases only. This methodology was applied on four map sheets in 1:10,000 scale in a coal mining region in the town of Karviná and its environs in the direction to the City of Ostrava (Czech Republic). Extensive changes caused by underground mining have been identified in the study area and the implementation of the suggested maps may help to deal with the issue in terms of land development by means of land use planning.

STUDIES DETERMINING THE AGGRESSIVENESS OF WATER IN GEOTECHNICAL PRACTICE

The aim of this publication is to study realization of aggressiveness of water in engineering geological and geotechnical practice. Determination of water aggressiveness is important for the knowledge of effect of concrete and steel. In the case that water is aggressive to concrete, located in the foundation structure, can be disturbed statics of the building or other malfunctions. Similar problems may occur in the case of steel elements. Moreover, various pipelines are steel pipes, which can be accelerated corrosion damaged. Determination of aggressiveness is thus one of the important goals engineering geological and geotechnical survey.

ANALYSIS OF VARIOUS TYPES OF ENGINEERING GEOLOGICAL MAPS

Engineering geological maps are an important tool for the implementation of geological engineering surveys and research. This is a different view of engineering geological conditions in topographic maps. The aim of this publication is to provide analysis of character engineering geological maps in the Czech Republic. Each of engineering geological maps gives specific knowledge about the state of engineering geological conditions. These are displayed on the basis of a methodological approach according to the type of maps in a given scale. Subsequently, various different types of maps gives possibility of practical use for the building survey with different structure and character of engineering geological information. Analysis of the state maps is very important for engineering geological, geotechnical and construction practice.

Use of geological databases for geotechnical practice

The use of various geological databases is very important for construction practice. It brings a lot of important information that can be applied in geotechnical survey. We must remember that in the Czech Republic took place a number of different engineering geological surveys and research. Their results data are available in the final reports, which are centrally archived. Very convenient and economically preferred is to use the information obtained in previous works. It is possible only when we realize the research on the territory, in which has been in the past performed works. It is geological database boreholes, final reports, landslides and others.