Karst Hazards Research Articles

Knowledge graph-driven mountain railway alignment optimization integrating karst hazard assessment

Karst hazard is a considerable threat that should be considered in railway alignment design for mountainous regions with dense water systems. Nevertheless, alignment design principles in karst regions have not been systematically studied. Moreover, a quantitative karst hazard assessment model is currently lacking for automated alignment optimization. To solve the above problems, based on the analyses of karst inducing factors and hazard representation, the railway alignment design principles in karst regions are summarized through an event tree. A highly-coupled knowledge graph (called KaRAD-KG) modeling method is proposed. Then, a bi-objective alignment optimization model considering railway construction cost and karst hazard (mainly including hazard components of synclinal karst, anticlinal karst and karst depression) is constructed. To solve the optimization model, a knowledge-driven distance transform algorithm incorporating a karst hazard assessment method and a multicriteria tournament decision method is customized. Finally, the application in a real-world case indicates that the proposed method can generate an alignment which reduces construction cost by 3.39 % and karst hazard by 18.73 % compared to the best manually-designed alternative, which verifies the effectiveness of this method for assisting actual railway alignment design in a karst-dense mountainous region.

Study on field and numerical analysis of karst collapse as railway hazard

The vulnerability of karst ecosystems and the weak mechanical performance of caves pose hidden risks in railways, leading to increased karst collapses. To analyse karst collapse as a railway hazard, the Beijing–Guangzhou railway line in China was selected to identify karst features, using the multi-source frequency domain method because of its operational advantages. Abaqus was also used to numerically analyse the factors (dynamic loading, groundwater fluctuations, over-burden thickness) affecting the collapse mechanism. The study reveals diverse stratigraphy, transitioning from a Quaternary layer to stable rock formations. A notable finding is that the presence of a karst cavity in the railway embankment significantly increases the vertical dynamic displacements, particularly within the soil layer, by 72%, highlighting the significant impact of karst sections on soil dynamics. The study also reveals that due to the groundwater table fluctuations from the subsoil surface to the subgrade surface, the maximum displacement increases by 73% in the subgrade section of the railway embankment. The authors consider soil overburden thickness to validate confirmation of reliability through field data and theoretical study. The findings offer crucial insights for managing karst hazards, enhancing railway safety and ensuring durable infrastructure in challenging geological conditions.

IMPACT OF URBAN LAND ON THE RISKS OF KARST PROCESSES IN THE NPP LOCATION AREA (ON THE EXAMPLE OF RIVNE NPP)

The aim of the article is to assess the impact of urbanized areas on the risk of developing karst processes in the area of nuclear power plant location and on the safety of the plant (using the example of the Rivne nuclear power plant). Karst features in the area around the Rivne nuclear power plant were visualized using GIS methods. Systematization of karst hazards was carried out with regard to their impact on the structural integrity and safety of the long-term operation of the Rivne nuclear power plant. The impact of urbanized areas on the geological environment was assessed, and a correlation was established between urbanization factors and the activation of karst-suffusion processes. It is shown that urbanization can contribute to the emergence of karst manifestations and, as a result, to threaten to the safety of NNP. Approaches aimed at improving the assessment of karst hazards, monitoring of the main factors of their activation, and managing urbanized areas to increase the safety of nuclear power plants were proposed.

Application of 2D Electrical Resistivity Method for Detections of Subsurface Karst Hazards Within the State Company for Glass and Refractories in Ar-Ramadi City, Iraq

The electrical resistivity method has been applied to detect the subsurface karst hazards using Dipole-dipole and Wenner – Schlumberger arrays with a-spacing equal to 1m and n-factor 6 at three selected stations within the State Company for Glass and Refractories in Al-Ramadi City, Iraq. The results indicate that the area formed a weakness zone as two separated zones, the first at a depth in the range of 2.5-5 m within the quaternary deposits and the second weakness zone within the Injana Formation deposits at an approximate depth range of 7 – >12 m. The investigation advises conducting physical, chemical, and engineering site investigations to decide the suitable treatment techniques to solve these problems.

On the issue of determining the dimensions of the rock massif cavity sufficient for the formation of a sinkhole in the overlying soil stratum

Introduction. The procedure currently recommended for karst hazard assessment includes a comparison of the cavity dimensions at the top of the karst massif with a “critical” value, sufficient for a shift of the cylindrical volume in the soil stratum. The scheme of calculating the “critical” value, proposed 40 years ago, is widely used due to its proven efficiency. However, in some cases, this procedure leads to an incorrect assessment of sinkhole development conditions, i.e., to incorrect decisions about the parameters of anti-karst measures.Aim. To adjust the procedure for calculating the “critical dimensions”, depending on the stratum structure and soil characteristics, as well as the load from the foundation.Materials and methods. The calculation formulas, transformed for computer calculations, are corrected by the introduction of a variable stability factor, the refinement of the schemes for accounting the effect of a surface load on the forces, acting along the side surface of the “shifting” volume, as well as by accounting, under the fulfillment of conditions for the general stability of a soil cylinder, the possibility of destroying the lower soil bearing layer, which is modeled as the clamped plate, loaded according to two different schemes depending on the properties of overlying soils.Results. The results of comparative calculations performed using the Mathcad software package for “standard” conditions are analyzed, and conclusions about the significance of the proposed corrections are drawn.Conclusion. When determining critical dimensions, it is necessary to introduce the values of the stability coefficient for the “shifting” soil volume, which are standard for geotechnics. In the case of using slab foundations, recommended in “karst-hazardous” areas, the effect of a surface load on the soil shift should be taken into account only when determining horizontal stresses on the side surface. Moreover, accounting can be carried out according to simple, but sufficiently justified, schemes. When the possibility of the lower layer destruction is accounted, the formation of a sinkhole is predicted at a smaller cavity span as compared to the proposed procedures.

Application of lineament-geodynamic analysis for assessment of karst hazard on the example of the Chayanda–ESPO oil pipeline route

The relevance of the work is due to the need to improve the methods for monitoring engineering structures of oil and gas transport in sparsely populated and hard-to-reach regions. To ensure the safe operation of pipeline systems, it is proposed to use remote sensing data to establish both the spatial position of the object and the activation centers of undesirable geological processes (karst, solifluction, landslide processes, etc.). As the main factor influencing the activation of such processes, it is definitely worth noting the tectonic disturbances of the territory. The research aimed at detecting and extracting special tectonic structures – lineaments – is today an important analytical method for finding relationships between the geodynamics of a territory and various geological processes. Purpose of the work – identification of lineaments and compilation of a general picture of tectonic activity along the pipeline route to assess their impact on the activation of karst sinkholes. Research methods. The main focus is on the construction and extraction of lineaments from a digital elevation model using the tools of the PCI Geomatica and ArcGis programs with their subsequent verification. In addition to construction, visual and analytical numerical data are presented to determine the relationship between the parameters of tectonic fracturing and karst manifestations. Results. The article presents the results of the influence of tectonics on karst manifestations within the route of an oil pipeline located in difficult engineering-geological and cryological conditions in southern Yakutia. Detailed maps of tectonic activity and distribution of lineaments in the study area have been developed, compiled on the basis of engineering-geological materials and decoding of digital elevation models (satellite images). The obtained results of the density of the general tectonic jointing showed a close connection with the previously discovered karst manifestations within the route. Conclusions. The application of an integrated approach to the consideration of geodynamic activity makes it possible to improve approaches to the description and study of territories that are complex in terms of engineering and geological parameters. Lineament-geodynamic analysis proves the need to consider tectonic fracturing as the main factor influencing karst activation.

Karst hazard assessment in the design of a residential complex in Moscow

The composition and content of necessary engineering-geological research providing accident-free operation of buildings and constructions in karst areas are considered. These studies include karst hazard assessment and rational selection of karst protection measures. The results of the prognostic assessment of karst sinkhole formation possibility on the territory of about 4 hectares, allocated for construction of the first stage of the complex of residential buildings of different numbers of floors in the northwest of Moscow, are presented. The basis was the results of site investigations, during which, in particular, several dozen boreholes were drilled to uncover soluble rocks. Karst hazard assessment included an in-depth analysis of engineering-geological conditions of the future construction site and adjacent territories and took into account the possibility of the occurrence of karst sinkholes of different genetic types in this city area. When building forecasts and karst risk assessment, calculated methods of probabilistic and deterministic character were used, allowing to determine the necessary conditions and parameters of karst sinkhole formation in quantitative terms. The results of the karst hazard assessment were considered when selecting karst protection methods.

Карстоопасность территории архитектурно-этнографического музея «Хохловка»

Exogenous geologic processes (EGP) on the territory of Perm Krai have a wide development. In this list, karst occupies a special position, as this process is widespread and, in addition, can serve as a catalyst for associated hazardous geological processes. At the request of the management of the State Regional Budgetary Cultural Institution "Perm Regional Museum of History" the authors conducted a reconnaissance survey of karst occurrences in the territory of the architectural and ethnographic museum "Khokhlovka" to assess the geological risks and to ensure the safe operation of cultural heritage object, non-capital structures and engineering facilities. This article presents the results of preliminary assessment of karst hazard of the territory, based on the analysis of stock materials, remote sensing data and field reconnaissance survey.

Geotechnical Integrated Approach to evaluate the karst hazard potentiality in the Qatar Coastal Eocene carbonate bedrocks

Geotechnical Integrated Approach to evaluate the karst hazard potentiality in the Qatar Coastal Eocene carbonate bedrocks

Сравнительный анализ изучения карстовых процессов на урбанизированных территориях и месторождениях строительного гипса

Natural and anthropogenic factors leading to the collapse zones formation and methods of studying karst processes for urbanized territories and deposits of gypsum plaster are characterized. Comparative analysis shows that the study of karst processes both in urbanized areas and in deposits of gypsum plaster are similar, but their essence is different for the assessment of the karst hazard. The possibility of applying the results of studying karst processes in urbanized territories to deposits of gypsum plaster and vice versa is considered. Recommended karstological studies at all ages and stages of geological exploration are given.

Use of electrical Resistivity tomography (ERT) and electromagnetic induction (EMI) methods to Characterize Karst Hazards in north-eastern of Algeria

Sinkholes are natural phenomena caused by the dissolution of limestone rocks due to the infiltration of acidic surface water. Initially, this infiltration creates voids, and then a sudden collapse occurs when the roof structure fails to support the weight load of the overlying deposits. In Algeria, a sinkhole occurred in February 2015 after a severe snowstorm, on an agricultural field near the city of El Ouldja ( South-Eastern Setif). The sinkhole occurred only after the dissolution of a quaternary lacustrine limestone. This dissolution created a karstic cavity, covered by an alluvial deposit. These alluvium deposits progressively pulled down from the base to the top through a sediment removal phenomenon at the deep karstic cavity opening. The sinkhole is circular with 16-m diameter and 16-m deep. This phenomenon represents a risk for local populations living with the fear of a worsening and expansion of the existing cavity or the formation of new sinkholes under the same circumstances. This work aims at identifying high-risk zones in the entire site surrounding the karstic collapse phenomenon through geological analysis of the sinkhole walls as well as two geophysical methods, namely, electrical resistivity tomography (ERT) and electromagnetic induction (EMI). Results revealed the existence of developing superficial karst cavities, in the NNW and SSE part, beneath the Quaternary alluvium of the study area, bordered by a fracture network. Such structures are a natural risk that needs to be considered not only for agricultural land management, but also for rural construction.

Institute of Mining and Chemical Industry

Introduction. There are the speleological and engineering-geological areas in karst studies. Engineeringgeological area has two aspects, the surface aspect including the construction of surface buildings in the areas with the karst hazard and the subsurface aspect of prevention and protection from karstification when developing mineral deposits. Although shafts in salt mines has been working since the Middle Ages, the salt karst is still the reason for the destruction of a lot of salt mines. Research aim is to reveal the physical and chemical mechanism of salt karst development and the reasons for accidents and flooding in salt mines. Methodology included the analysis of regular survey measurements of surface deformation, recording of brine manifestations in mine workings, chemical analyses in brines, hydraulic measurements at surface watercourses, direct determinations of brine aggression, geophysical research by the natural field method, vertical electrical sounding, etc. In recent years, in order to control surface deformation, the data from the radar survey have been used. Results. A clue to the mechanism of salt karst responsible for accidents is the theory of hydrodynamic systems by A. M. Ovchinnikov, the elements of which are the areas of accumulation, transit, and discharge. Brine motion is in the supra-salt reservoir. The trajectory of brine motion is determined by the relief of the salt table. Pressure flow take up the elevated terrain. Accumulation areas are confined to stream corridors permeating the low-permeability strata which covers the salt. The area of transit distinguishes between the zone of the pressure flow and the vertical slot where the brines move in the gravity turbulent conditions. Mine workings make up the discharge area. Within them under the action of aggressive brines triangular niches develop. Pillars undercut results in their collapse and surface sink. Summary. Salt karst development mechanism disclosure has made it possible to propose the methods for predicting its effect and the ways of predicting flooding in salt mines.

Algorithm for predicting of the transition of a key point of geodynamic control to the risk zone

The article discusses the algorithm for assessing changes in the level of risk of karst hazard of the territory based on the forecasting of the number of holes depending on the water level. Based on the results of the analysis, the values of bifurcation parameters are determined, the transition through which sharply increases the formation of new holes. The article provides the developed block diagram of the neural network for assessing the dynamics of the occurrence of holes, as well as an algorithm for generating a predictive estimate of the number of holes. An analysis of the occurrence of the number of holes is carried out on the basis of water level data in the Oka River. The results of spline interpolation of the data are presented in the dependence on the number of holes on the dynamics of the water level in the river for the current and previous year. Practical verification of the developed algorithm was carried out on the basis of the new set of data on the water level in the river and the number of holes. The developed algorithm can be used in predicting the spread (leaching from the soil) of pollutants.

Mapping geological risk in urban areas

The geological risk of economic losses was qualitatively assessed for the Moscow megacity proceeding from the combined consideration of geohazards operating in this territory and the vulnerability of urban environment. The map of geoecological conditions was built on the basis of assessing karst, suffosion, waterlogging, and landslide hazards in Moscow, and the schematic map of geological risk (scale 1: 50000) was compiled for the Moscow territory, representing risk as an integral parameter of probable damage caused by the considered geohazards and the anthropogenic load on the urban territory. The mapping procedure included four steps: grading and mapping exogenous geohazards, grading and mapping the vulnerability of urban environment (which is understood here as the city territory with the surface infrastructure) to these geohazards, distinguishing risk categories by the analysis of geohazard impact on urban environment, and compiling the resultant risk map by superposition of the integral map of exogenous geohazards and the vulnerability map. This qualitative approach provides reliable and sufficient data permitting urban planners to optimize investments in Moscow city development.

Ensuring the civil security in territorial entities

Subject. As the society faces more and more threats and risks, civil security issues become a priority. The civil security means the protection of a citizen from external and internal threats arising from the societal, natural and technological environments. Objectives. The study evaluates threats and civil security in territorial units. Methods. I applied methods of the comparative analysis, results of sociological surveys and official statistics. Results. What seems to put people at peril at the local level is mushrooming threats of emergencies. Evaluating the security of the urban environment, I should point out low road accident rates, good fire safety, more preventive public security actions for people and businesses. In the mean time, I mention weaknesses, such as buildings in residential areas that can be destroyed by land slides, residential areas exposed to karst hazards, floods in cities and houses during spring tides, few people having access to central communication channels, its obsolescence, low capacity and insufficient ramification of sewage networks, etc. Conclusions and Relevance. There should be a conceptual smart city model, which would refer to the public feedback on the urban environment. At the municipal level, I should prioritize the improvement of emergency prevention practices, expansion and development of video surveillance in publicly important places, air pollution monitoring, rehabilitation of the existing sewage network, geological surveys of karst hazards in urban areas, etc.

Risk Assessment for Karst Hazards at a Facility in Saudi Arabia—A Case Study

The boom in industrial and infrastructure construction in Saudi Arabia requires in-depth knowledge of the underground conditions to build a sustainable project. This paper gave a practical example of the challenges facing an existing facility built on a karstic limestone formation in 1970’s. Multiple geophysical techniques such as Microgravity, Electrical Resistivity Imaging, Vertical Seismic Velocity Profiling, Cross Hole Seismic Tomography, Ground Penetration Radar, Multi-Channel Analysis of Surface Waves, as well as boreholes and down-hole video imagery, were deployed through the journey of assessing the karst associated hazards of potential sinkholes or general subsidence. This paper described the karst processes, site geology, geophysical and geotechnical exploration program, and characterizes the subsurface karst conditions at the eastern province of Kingdom of Saudi Arabia. Results and findings of preliminary, geotechnical and geophysical investigations have been utilized to identify the major factors influencing the karst formation. Analyses and integration of obtained results to estimate the type and magnitude of risk affected the major components of industrial facility at the project site using well-known statistical approach were presented in this paper. Consequently number of remedial measures implemented to combating the experienced and expected karst hazards at the studied industrial facility placed in karstified landform are given. A model for using integrated geophysical and geotechnical techniques to assess karst-related risks to a facility was further explored herein.

Районирование закарстованных территорий Калужской области с применением интегрального подхода с целью выявления благоприятных площадей для строительства

The article considers 17 factors of natural structure of the territory of the Kaluga region divided into 4 groups: geological, hydrogeological, structural-tectonic and geomorphological. The relationship between each factor and the development of surface karst forms has been analyzed. Laws of distribution of karst forms and factors boundary values corresponding to intervals with different degree of danger are defined. The final assessment of the karst hazard was carried out by means of ESRI ArcGIS 10 using an integrated approach that takes into account the role of each factor in the development of the karst process as much as possible.

GPR surveys for the prevention of karst risk in underground gypsum quarries

The investigation and prediction of geological anomalies in underground quarries is fundamental to ensure safety, efficiency and economic convenience of the exploitation. For these aims, non-destructive geophysical surveys may be an effective alternative approach to classical destructive prospecting techniques (i.e. horizontal drilling), with great advantages particularly in complex geological frameworks and in areas subjected to specific geo-hazards. Ground Penetrating Radar (GPR), for its high resolution, is a suitable technique for underground excavations, particularly for the identification of water bodies, fissures and fractured rocks. The present study is focused on the application of GPR for the prediction of karst structures in underground gypsum quarries. Karst phenomenon is a main risk factor for gypsum orebodies, where large cavities may be intersected by the excavation. The possible filling with clay or pressurized water of these cavities exponentially increases the dangerousness of the phenomenon, due to swelling problems and violent water inrushes. The aim of the present study is to propose, through modelling and field surveys, a description of GPR outputs for principal elements of karst hazard in gypsum bodies, with particular attention to the discrimination of fillings (air, water or clay).

Evaporite Dissolution Rate through an on-site Experiment into Piezometric Tubes Applied to the Real Case-Study of Quinis (NE Italy)

The present paper deals with a field experiments on evaporite rock samples and groundwater investigations in the Quinis test site, a hamlet of the Enemonzo municipality in NE Italy, were sinkholes occurred in the past and are still occurring causing severe damage to the existing infrastructures. The area is characterised by a Carnian evaporitic bedrock made of gypsum and anhydrite mantled by alluvial and colluvial deposits. In order to evaluate the loss of weight and volume of the subcropping evaporites as responsible for sinkholes, a field-experiment was carried out. Inside seven piezometers, at different depths, evaporitic rock samples were exposed to the naturally occurring variable climatic conditions such as degree of humidity, different air flow and hydrodynamic. The rock samples were installed at the beginning of April 2017 in the dry sections of piezometric tubes, in the vadose zone and in the phreatic zone. Data related to water level fluctuations were recorded by using data-logger devices and highlight significant changes in the water table. After 13 months of data recording (May 2018), rock samples were removed, reweighted and the volume loss measured. In addition, water from piezometer-experiment, representative of the groundwater circulation, were collected at different depths. The obtained results indicate that rock sample reduction is dependent on the hydrological regime and water chemistry and not on the number of days during which the samples remained submersed. In particular, the water geochemistry highlights the possible role in gypsum/anhydrite dissolution due to NaCl water admixing in a complex scenario. In additional, the geochemical data highlight the occurrence of some potentially toxic elements (As, Fe, Mn) at concentrations of concern in some water. This approach represents a novel contribution in the study of karst hazard in evaporites adding a tile to the knowledge of the fast evolutionary processes which cause sinkhole formation.

Assessment of karst hazard in engineering surveys: a review of Russian regulatory technical documents

Engineering surveys are a required part of the construction activity in accordance with the Urban Planning Code of the Russian Federation No. 190-FZ of December 29, 2004 and the Technical Regulations on the Safety of Buildings and Structures No. 384-ФЗ of December 30, 2009.The analysis of domestic regulatory technical documents containing the terms, requirements for the composition, volume and methods of studying hazardous territories is presented. Requirements for engineering surveys in karst development areas are most fully set out in SP 11-105-97 (Part II); TCH 302-50-95 RB; TSN 22-308-98 NN; TSN 11-301-2004Po, which are currently not valid. Issues of terminology are considered, problems in determining the normative indicators (sinkhole formation intensity and average diameter of karst sinkhole) are covered during the karst hazard assessment, in accordance with SP 11-105-97 (Part II). It is noted that it is necessary to make changes to a number of regulatory technical documents to eliminate contradictions and inconsistencies, especially in SP 22.13330.2016 "SNiP 2.02.01-83* Foundations of buildings and structures", SP 116.13330.2012 "SNiP 22-02-2003 Engineering Protection of Territories, buildings and structures from hazardous geological processes. Fundamental principles". The need to develop a new set of rules for the implementation of engineering surveys for construction on karst territories, in which it is supposed to take into account regional features of engineering surveys, is shown. It is proposed to take SP 11-105-97 (Part II) as a basis, in which the composition and volume of engineering and geological surveys are described in most detail and have not lost their relevance to the present.