Martin Bednarik

Landslide hazard and risk assessment: a case study from the Hlohovec–Sered’ landslide area in south-west Slovakia

Landslide hazard or susceptibility assessment is based on the selection of relevant factors which play a role on the slope instability, and it is assumed that landslides will occur at similar conditions to those in the past. The selected statistical method compares parametric maps with the landslide inventory map, and results are then extrapolated to the entire evaluated territory with a final product of landslide hazard or susceptibility map. Elements at risk are defined and analyzed in relation with landslide hazard, and their vulnerability is thus established. The landslide risk map presents risk scenarios and expected financial losses caused by landslides, and it utilizes prognoses and analyses arising from the landslide hazard map. However, especially the risk scenarios for future in a selected area have a significant importance, the literature generally consists of the landslide susceptibility assessment and papers which attempt to assess and construct the map of the landslide risk are not prevail. In the paper presented herein, landslide hazard and risk assessment using bivariate statistical analysis was applied in the landslide area between Hlohovec and Sered’ cities in the south-western Slovakia, and methodology for the risk assessment was explained in detail.

Neural computing models for prediction of permeability coefficient of coarse-grained soils

Correlations are very significant from the earliest days; in some cases, it is essential as it is difficult to measure the amount directly, and in other cases it is desirable to ascertain the results with other tests through correlations. Soft computing techniques are now being used as alternate statistical tool, and new techniques such as artificial neural networks, fuzzy inference systems, genetic algorithms, and their hybrids were employed for developing the predictive models to estimate the needed parameters, in the recent years. Determination of permeability coefficient (k) of soils is very important for the definition of hydraulic conductivity and is difficult, expensive, time-consuming, and involves destructive tests. In this paper, use of some soft computing techniques such as ANNs (MLP, RBF, etc.) and ANFIS (adaptive neuro-fuzzy inference system) for prediction of permeability of coarse-grained soils was described and compared. As a result of this paper, it was obtained that the all constructed soft computing models exhibited high performance for predicting k. In order to predict the permeability coefficient, ANN models having three inputs, one output were applied successfully and exhibited reliable predictions. However, all four different algorithms of ANN have almost the same prediction capability, and accuracy of MLP was relatively higher than RBF models. The ANFIS model for prediction of permeability coefficient revealed the most reliable prediction when compared with the ANN models, and the use of soft computing techniques will provide new approaches and methodologies in prediction of some parameters in soil mechanics.

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.

GIS-based kinematic slope instability and slope mass rating (SMR) maps: application to a railway route in Sivas (Turkey)

The paper discusses the use of kinematic stability and slope mass rating (SMR) maps in GIS based on field studies recording the relationships between the bedding/joint geometry relative to the orientation of the free face. The results indicated the potential for both planar and wedge type failures in many locations along a railway route. Whilst the results showed the procedure to be a useful first assessment of slope stability, it is recommended that the construction of the maps by kinematic slope stability and SMR analysis within the GIS medium should be used in conjunction with more sophisticated slope stability models taking into account of the material strengths, hydrostatic pressures, seepage forces, active forces, passive forces, etc.RésuméL’article considère l’utilisation de cartes présentant les conditions cinématiques de rupture de pente et un indice SMR de pente, dans un système d’information géographique, cartes établies à partir d’études de terrain comparant les attitudes respectives des pentes et des joints dans une masse rocheuse. Les résultats montrent que des ruptures planes et des ruptures de dièdres sont possibles en plusieurs endroits le long de la voie ferrée étudiée. La procédure est utile pour une première évaluation de la stabilité des pentes, mais il est recommandé que les cartes donnant les conditions cinématiques de rupture de pente et l’indice SMR de pente, dans un SIG, soient utilisées conjointement avec des modèles plus sophistiqués de stabilité des pentes prenant en compte les résistances des matériaux, les pressions hydrostatiques, les forces d’écoulement, les forces motrices, les forces résistantes, etc.

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.

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.

Evaluation of engineering-geological conditions for conurbation of Ostrava (Czech Republic) within GIS environment

The main aim of the presented study was to create a new type of engineering-geological maps for relative costs for foundation engineering. The newly proposed map in this paper can replace the formerly used maps of the suitability for foundation engineering which shows only the suitable and/or unsuitable sites and suggests the use of suitable areas for construction only. However, there are developed technologies that they can overcome the potential problems in unsuitable areas by relatively high costs. It means that unsuitable areas can also be used as construction areas. Therefore, the use of the newly proposed map of relative costs, which reflects the complexity of geo-factors by proportional category of larger, or smaller relative costs is satisfactory. Another part of this research was to assess various geo-factors (engineering-geological zones, workability of rocks, pre-Quaternary bedrock, flood land, radon hazard, mining subsidence and slope movements), which affect the foundation of future buildings. This study was carried out in the large industrial city of Ostrava in the Czech Republic with complicated engineering geological conditions and high anthropogenic influence factors including undermining. The use of complicated relationships is also generally difficult to be taken into account by the planners. Therefore, the use of the newly created synthetic map by planners is simple; even planners who are not geologists will be able to apply it easily.

An assessment on the use of bivariate, multivariate and soft computing techniques for collapse susceptibility in GIS environ

The paper presented herein compares and discusses the use of bivariate, multivariate and soft computing techniques for collapse susceptibility modelling. Conditional probability (CP), logistic regression (LR) and artificial neural networks (ANN) models representing the bivariate, multivariate and soft computing techniques were used in GIS based collapse susceptibility mapping in an area from Sivas basin (Turkey). Collapse-related factors, directly or indirectly related to the causes of collapse occurrence, such as distance from faults, slope angle and aspect, topographical elevation, distance from drainage, topographic wetness index (TWI), stream power index (SPI), Normalized Difference Vegetation Index (NDVI) by means of vegetation cover, distance from roads and settlements were used in the collapse susceptibility analyses. In the last stage of the analyses, collapse susceptibility maps were produced from the models, and they were then compared by means of their validations. However, Area Under Curve (AUC) values obtained from all three models showed that the map obtained from soft computing (ANN) model looks like more accurate than the other models, accuracies of all three models can be evaluated relatively similar. The results also showed that the conditional probability is an essential method in preparation of collapse susceptibility map and highly compatible with GIS operating features.

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.