Journal articles on the topic 'Suffosion surface'
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1
Shcherbakov, S. V., V. N. Kataev, D. R. Zolotarev, and T. G. Kovaleva. "COVERED KARST LANDFORMS: COMPLEXIFICATION OF METHODS TO ESTIMATION OF MORPHOMETRIC PARAMETERS IN ENGINEERING PURPOSES." Engineering Geology 13, no. 6 (December 21, 2018): 10–23. http://dx.doi.org/10.25296/1993-5056-2018-13-6-10-23.
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The research is aimed to search of optimal solution in integration of various methods for predicting the sizes of karst-suffosion deformations on the ground surface or at the base of shallow foundations. Necessity of integration is dictated by engineering-geological conditionsof the karst areas and the complexity of their reliable study with using modern approaches (drilling, geophysics etc.). From this point of view increasing of authenticity of the final forecast is in direct dependency from completeness of investigation of sizes of observed surface karstforms and features of behavior soils massif above the karst cavity. The mechanism of the karst process in the soils thickness is defined, first of all, by geological structure (thickness and interleaving of different soil layers), hydrogeological conditions and the physical-mechanicalproperties of soils. At the present day are known three basic mechanisms of soil deformation over karst cavity: karst-collapse, karst-suffosion and karst-suffosion-collapse mechanism. Even in the conditions of one site these mechanisms can be interleave during the year, which makesthe karst formation process hard-to-predict in part of diameters of sinkholes and subsidence zones. Today are known and applicable next four methods to estimations of possible sizes of karst-suffosion deformations: 1) method of analogy, 2) probabilistic method, 3) deterministic(calculated) method, 4) laboratory physical modeling method. Each of four methods for predicting the sizes of karst-suffosion deformations has its own advantages and disadvantages, which limit the possibility of using any one of them in different natural environments of karstdevelopment. To improve objectivity and reach necessity accuracy of estimation of diameters and depths of surface karst deformations in engineering-geological purposes a block-scheme of integrations of different forecasting methods is recommended. This scheme is based on the data about surface karst area, the depth of occurrence of karst rocks and level of responsibility of the projecting object.
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Latypov, A. I., A. N. Garaeva, and O. V. Luneva. "CHARACTERISTICS OF THE SUFFOSION HAZARD OF THE TERRITORY OF THE BUGULMA PLATEAU OF THE BUGULMA-BELEBEY UPLAND." Gruntovedenie 1, no. 18 (2022): 31–42. http://dx.doi.org/10.53278/2306-9139-2022-1-18-31-42.
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This work is devoted to the studies of the territory, located in the south-eastern part of the Republic of Tatarstan. Despite the high anthropogenic development of the territory (several large cities are located in this part of the Republic of Tatarstan, several oil fields are being developed, a number of large industrial plants operate), the engineering and geological study is significantly inferior to the western and central parts of the Republic of Tatarstan.This is due to the wide spread of eluvial soils in this part of the territory, which everywhere come out on the daytime surface and are the basis of the foundations of buildings and structures. Except the high degree of diversity of physical and mechanical properties, as in area so in depth rates, these soils have a high degree of suffosion instability.This creates serious problems while design of the bases of buildings and structures composed of eluvial soils. Another problem is created by the fact that anthropogenic development of territories contributes to a significant activation of suffosionprocesses, and can lead to serious deformations of the foundations of buildings and structures.The purpose of the performed studies was to conduct a comprehensive engineering and geological assessment of eluvial soils with the identification of types of new weathering crusts, as well as an assessment of the suffusion danger of the Bugulma plateau territory, taking into account the parameters of fracturing and suffosion stability of soils.The authors present the results of the typification of laboratory studies, the main physical and mechanical properties, mineral composition and spatial patterns of the distribution of suffusion dangerous soils on the territory of the Bugulma plateau of the Bugulma-Belebey upland.Lithological varieties of eluvial soils are identified all forms of weathering crust in the studied area are described in detail. Based on spatial analysis in the ArcMap 10.8 software environment, a map of geological and geomorphological processes of the Bugulma plateau territory was constructed, karst-suffusion processes were classified according to geological, geomorphological, hydrogeological conditions in accordance with the types of geological environment.The assessment of the suffosion danger of soils of the studied territory was carried out, the parameters of fracturing and suffosion stability were calculated. It is established that all the differences of structureless eluvium developed in the upper part of the geological cross section within the studied territory are potentially suffosion-unstable. The calculations of suffosion damage have shown that studied area in terms of the intensity of Failure formation belongs mainly to moderately dangerous, and in river valleys and terraces deposit of large rivers like Ik, Sheshma, StepnoyZay — to moderately dangerous. The results will be useful both for making preliminary design decisions on undeveloped territories and for predicting the development of unfavorable engineering and geological processes on the areas of existing buildings and structures.
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Mikailsoy, F. D., and E. V. Shein. "Analytical Mathematical Model of Chemical Suffosion while Washing Saline Soils." Eurasian Soil Science 53, no. 9 (September 2020): 1247–54. http://dx.doi.org/10.1134/s1064229320090100.
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Jiang, Zhen Wei, and Qi Yao Wang. "Study on the Formation and Repeated Opening Mechanism of Ground Fissures under the Role of Surface Water." Advanced Materials Research 243-249 (May 2011): 3238–43. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.3238.
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The role of surface water is also the main reason for the formation and development of ground fissures. Five mechanisms were obtained on the formation of ground fissures under the role of surface water in the loess region through theoretical analysis, i.e., fissuring mechanism induced by loess collapsible deformation; that induced by dissolution and suffosion; that induced by water-loss shrinkage; that induced by hydraulic pressure; that induced by humidification and softening. As the role of surface water had certain phased and periodic characteristics, repeated fissuring mechanism of ground fissures was analyzed. Consequently, it could be known that the repeated fissuring of ground fissures under the role of surface water was mainly shown as horizontal openness and closure with little vertical displacement, and fissures were intersected and cross-cut with each other to form a complex network structure.
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Kochev, A. D., L. G. Chertkov, and I. L. Zayonts. "KARST-SUFFOSION PROCESSES ON THE TERRITORY OF MOSCOW AND THE PROBLEM OF THEIR HAZARD ASSESSMENT." Engineering Geology 13, no. 6 (December 21, 2018): 24–32. http://dx.doi.org/10.25296/1993-5056-2018-13-6-24-32.
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The study of the processes leading to the formation of sinkholes on the surface of the earth on the territory of Moscow began in the late 60s of the last century. To date, 42 karst-suffusion funnels have been identified. Analysis of all the studied city sinkholes with their confirmedassociation with the ancient karst showed that their average size of these forms in the plan is 13.1 m, varying from 1.5 to 53 m. At the same time, all calculations of possible diameters of the sinkholes made during engineering-geological surveys in Moscow are usually reduced tovalues less than 3 m, less often they reach 5 – 6 m. The overwhelming number of specialists speak about the urgent need to change and improve the content of the set of rules in terms of engineering-geological surveys in karst areas. Existing calculation models are often usedunreasonably, often the result is tailored to the “necessary” values for designing engineers and builders. Hazard assessment of modern karstsuffosion processes, carried out on the basis of the “Hazard maps of ancient karst forms and modern karst-suffusion processes” (scale 1:10000) created by the specialists of the Sergeev Institute of Environmental Geoscience RAS and the State Unitary Enterprise Mosgorgeotrest in 2012, which determines the need for regional zoning using more meaningful criteria. The paper proposes a new approach, which takes intoaccount the results of the typification of geological-hydrogeological conditions of 42 karst-suffusion sinkholes formed in Moscow. In this case, the hazard prediction is carried out on the basis of an analysis of natural conditions, where a hazardous process has already beenimplemented with access to the surface in the form of such sinkholes.
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Makarova, N. V., A. S. Gusel’tsev, T. V. Sukhanova, and V. M. Makeev. "Geological conditions of suffosion processes development and their acitivity at Sal-Don neotectonic upland (Rostov NPP area)." Геоэкология. Инженерная геология. Гидрогеология. Геокриология, no. 6 (December 21, 2019): 19–29. http://dx.doi.org/10.31857/s0869-78092019619-29.
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Suffusion processes and their influence on the stability of the Rostov NPP site are investigated. Geological, tectonic, geomorphological, hydrogeological conditions, as well as anthropogenic factors affect the development and intensification of suffusion. These conditions and factors include the following: predominance of Pliocene and Quaternary sands in the geological cross-section; the presence of clay aquiclude underlying sandy deposits; natural seasonal and human-induced fluctuations of the water level in the Tsimlyansk reservoir; as well as pumping of groundwater. The buried relief in the shape of a slope dissected by erosional gullies are also of great importance. These erosional depressions are probably channels, along which sand is removed to the Tsimlyansk water reservoir. It is suffusion that may be the reason of surface subsidence that causes deformation of ground basements and inclinations of some engineering structures at NPP. Recent tectonic conditions control the formation of active zones and fracturing in the mantle deposits favoring percolation of surface water. Suffusion amplified by tectonic and technogenic factors results in the subsidence of soil basement in some places at the NPP site, displacement of reference marks, and inclination of engineering structures.
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Fernandes Ferreira, Cristiano, Yawar Hussain, and Rogério Uagoda. "A semi-automatic approach for doline mapping in Brazilian covered karst: the way forward to vulnerability assessment." Acta Carsologica 51, no. 1 (December 8, 2022): 19–31. http://dx.doi.org/10.3986/ac.v51i1.10011.
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Doline mapping is paramount in the vulnerability and risk assessment of the underground karst environment by identifying cave-ground connectivity points at the surface. However, manual mapping is labour-intensive, slow and subjective, especially on a large scale. Therefore, the present study adopted a GIS-based semi-automatic approach for mapping large and medium-sized depressions/dolines in the Corrente river basin in Brazil, with a particular focus on the environmentally preserved areas of river Vermelho (APANRV Portuguese abbreviation) using remote sensing (DEM and Google Earth imagery) and field-based observations. Seven typical dolines forms (e.g., cockpit with drain insertion, collapse, collapse with river capture, suffosion, solution, cover collapse, and buried) are found from extensive field surveys. As an outcome of the proposed approach, two hundred and thirty-two medium to large-sized dolines have been identified and categorised into three main groups based on the cave density and local geology G1, G2, and G3. The high density of identified dolines (164 known caves) in G1 provides reconnaissance for future speleological works in the preserved areas. Additionally, the presence of a considerable number of dolines in the adjoining areas (G2 and G3) stresses the need to revise the existing boundaries of the APANRV. Results correlate well with the dolines sites marked using field surveys and Google Earth images. This doline mapping may help researchers in the groundwater vulnerability assessment and the protection of speleological heritage preserved in the caves.
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Eremina, Olga, Irina Kozliakova, Nadezhda Anisimova, and Irina Kozhevnikova. "Assessment of exogenous geological hazards in Moscow, Russia." Journal of Nepal Geological Society 55, no. 1 (June 4, 2018): 133–40. http://dx.doi.org/10.3126/jngs.v55i1.22802.
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Exogenous geological processes are exerting a significant impact on urban geo environment in Moscow endangering both surface and subsurface constructions. For surface construction, the principle geohazards in Moscow are karst-suffosion sinkholes, land subsidence, landslides, and waterlogging. The subsurface construction is endangered by karstification and fracturing of limestone, decompaction and swelling of clay, quicksand phenomena, and groundwater breakthrough to tunnels. Different methods are applied to study geohazards depending on the purpose and the scale of study. At the preliminary investigation stage, small-scale mapping and zoning of city surface or subsurface appears to be the most appropriate for the qualitative assessment of the risk of economic losses caused by exogenous geohazards. Assessment of the geological risk in Moscow was carried out separately for already existing urban infrastructure and for future planned construction. For existing surface urban infrastructure, geological risk is considered to be an integral parameter of probable damage caused by geohazards and the anthropogenic load on the specific territories. The main aim of risk mapping in this case is outlining the territories, for which restrictions and prohibitions should be imposed for further urban engineering development. For future subsurface urban construction, the risk-analysis consists in assessing the impact of geohazards on the engineering structure by comparing the future expenditures for the construction and operation under different engineering geological conditions. The risk maps in this case will help planners to compare and make alternative project decisions in order to minimize the cost in future economic expenditures. Both approaches are successfully approved in this investigation in Moscow.
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Kozliakova, Irina V., Olga N. Eremina, Nadezhda G. Anisimova, and Irina A. Kozhevnikova. "Specific Features Of Geological Risk Assessment In Moscow." GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY 12, no. 4 (December 31, 2019): 159–74. http://dx.doi.org/10.24057/2071-9388-2019-85.
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The paper describes approaches to assessing geohazards and georisk of economic losses in Moscow. It is shown that for surface construction, the principle geohazards in Moscow are karst-suffosion sinkholes, land subsidence, landslides, and waterlogging. The subsurface construction is endangered by karstification and fracturing of limestone, decompaction, and swelling of clay, quicksand phenomena, and groundwater breakthrough to tunnels. The different procedures for the assessment of geological risk in Moscow have been suggested for already existing urban infrastructure and for future planned construction. For existing surface urban infrastructure, geological risk is considered to be an integral parameter of probable damage caused by geohazards and the anthropogenic load on the specific territories. The main aim of risk mapping in this case is outlining the territories, for which restrictions and prohibitions should be imposed for further urban engineering development. For future subsurface urban construction, the risk-analysis consists in assessing the impact of geohazards on the engineering structure by comparing the future expenditures for the construction and operation under different engineering geological conditions. The procedures of risk mapping elaborated for both approaches are described; the typification schemes are listed; and the relevant risk maps built for the Moscow territory are provided. The risk maps will help planners to compare and make alternative project decisions in order to minimize the cost in future economic expenditures. Both approaches are successfully approved in Moscow.
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Wilk, Krzysztof. "Hazards for buildings and structures caused by flood conditions." E3S Web of Conferences 45 (2018): 00101. http://dx.doi.org/10.1051/e3sconf/20184500101.
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Floods are one of the common natural phenomena that can cause a huge danger to people and building objects located in flood plains. The particularly severe effects of such disasters are felt in heavily urbanized areas [1, 2]. The development of river valleys causes difficulties in the flow of flood water and the protective embankments limit the possibility of the temporary accumulation of water. The consequence of this situation is increasing the level of the flood wave and thereby intensifying its negative impact. Damages to the building during inundations can be the result of not only the direct activity of the flood wave and surface water, but also changes in groundwater flow conditions, including the increase of their piezometric level [3, 4]. An increasing of groundwater pressure can intensify or initiate new phenomena related to permeability (suffosion, colmatation, etc.) and consequently conduce disadvantageous changes of soil substrate parameters [5]. The influence of such processes can be revealed later, after the floods stage recede. The local conditions of water flow and the ground structure have a direct impact on the probability of occurrence of specific phenomena threatening construction objects (initiated by floods).
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Kołodyńska-Gawrysiak, Renata. "Grain-size and microstructure of the loess from closed depressions in the Nałęczów Plateau (East Poland)." Polish Journal of Soil Science 52, no. 2 (December 28, 2019): 295. http://dx.doi.org/10.17951/pjss.2019.52.2.295.
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<p>The investigation was conducted in the eastern part of the Nałęczów Plateau, a region of the Lublin Upland, in eastern Poland. The loess cover of this region was formed mainly during the last glaciation, and loess accumulation lasted until 15,000–12,000 BP. The undulating loess plateau with numerous oval-shaped closed depressions (CDs) is the main landform in the study area. Particle size distribution and SEM analyses were conducted for loess profiles under the bottoms and on the slopes of 4 CDs. Grain-size distribution characteristics as well as qualitative and quantitative micromorphological characteristics of the the loess forming the bottoms and slopes of the depressions were compared and discussed. It was documented that the differences between the loess forming the bottoms and slopes of the depressions are insignificant in the case of clay fraction content, but are considerable in the case of microstructure characteristics. The differences documented result from the impact of syn- and post-depositional diagenetic processes related mainly to suffosion and hydroconsolidation occurring under the influence of water. A quantitative assessment of the morphological effects of these processes was carried out in the context of the origin of closed depressions. The morphological effect of Holocene diagenetic processes was manifested in the deepening of the initial closed depressions formed previously under the influence of primary morphogenetic processes.</p>
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Yuan, Changfeng, Zhenhui Hu, Zhen Zhu, Zijin Yuan, Yanxiang Fan, Hui Guan, and Liang Li. "Numerical Simulation of Seepage and Deformation in Excavation of a Deep Foundation Pit under Water-Rich Fractured Intrusive Rock." Geofluids 2021 (February 12, 2021): 1–10. http://dx.doi.org/10.1155/2021/6628882.
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Water is one of the major risk sources in the excavation of deep-large foundation pits in a water-rich area. The presence of intrusive broken diorite porphyrite in the stratum aggravates the risk level of deep foundation pits. Based on a geological survey report and design documents of parameter information, MIDAS/GTS software was used to perform the numerical simulation of an engineering example of a deep foundation pit project of ultradeep and water-rich intrusion into the broken rock station of subway line 4 in a city. The simulation results show the characteristics of seepage path evolution, seepage aggregation areas and points, and the effect of seepage on the deformation of a deep foundation pit during the whole construction of this deep foundation pit. The results show that with the precipitation-excavation of the deep foundation pit, the pore water pressure at the bottom of the foundation pit follows a distribution of three “concave” shapes. High-permeability pressure zones are found around the foundation pit, intruding broken diorite porphyrite zones, and middle coarse sand zones. With further excavation of the foundation pit, the seepage pressure in the middle part of the foundation pit gradually decreases, and the two “concave” distributions in the middle gradually merge together. After excavation to the bottom of the pit, the pore water pressure at the bottom is distributed in two asymmetrical “concave” shapes, and the maximum peak of pore water pressure is found at the intrusion of fractured porphyrites prone to water inrush. The four corners of the foundation pit are prone to form seepage accumulation zones; therefore, suffosion and piping zones are formed. The surface settlement caused by excavation is found to be the largest along the longitudinal axis of the deep foundation pit, whereas the largest deformation is found near the foundation pit side in the horizontal axis direction of the foundation pit. With the excavation of the deep foundation pit, the diaphragm wall converges to the foundation pit with the maximum deformation reaching about 25 mm. After the first precipitation-excavation of the deep foundation pit to the silty clay and the bottom of the pit with the largest uplift, with further precipitation-excavation of the deep foundation pit, the uplift at the bottom of the deep foundation pit changes only slightly.
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Cardoso de Salis, Hugo Henrique, Adriana Monteiro da Costa, João Herbert Moreira Vianna, Marysol Azeneth Schuler, Annika Künne, Luís Filipe Sanches Fernandes, and Fernando António Leal Pacheco. "Hydrologic Modeling for Sustainable Water Resources Management in Urbanized Karst Areas." International Journal of Environmental Research and Public Health 16, no. 14 (July 16, 2019): 2542. http://dx.doi.org/10.3390/ijerph16142542.
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The potential of karst aquifers as a drinking water resource is substantial because of their large storage capacity gained in the course of carbonate dissolution. Carbonate dissolution and consequent development of preferential paths are also the reasons for the complex behavior of these aquifers as regards surface and underground flow. Hydrological modeling is therefore of paramount importance for an adequate assessment of flow components in catchments shaped on karsts. The cross tabulation of such components with geology, soils, and land use data in Geographic Information Systems helps decision makers to set up sustainable groundwater abstractions and allocate areas for storage of quality surface water, in the context of conjunctive water resources management. In the present study, a hydrologic modeling using the JAMS J2000 software was conducted in a karst area of Jequitiba River basin located near the Sete Lagoas town in the state of Minas Gerais, Brazil. The results revealed a very high surface water component explained by urbanization of Sete Lagoas, which hampers the recharge of 7.9 hm3 yr−1 of storm water. They also exposed a very large negative difference (−8.3 hm3 yr−1) between groundwater availability (6.3 hm3 yr−1) and current groundwater abstraction from the karst aquifer (14.6 hm3 yr−1), which is in keeping with previously reported water table declines around drilled wells that can reach 48 m in old wells used for public water supply. Artificial recharge of excess surface flow is not recommended within the urban areas, given the high risk of groundwater contamination with metals and hydrocarbons potentially transported in storm water, as well as development of suffosional sinkholes as a consequence of concentrated storm flow. The surface component could however be stored in small dams in forested areas from the catchment headwaters and diverted to the urban area to complement the drinking water supply. The percolation in soil was estimated to be high in areas used for agriculture and pastures. The implementation of correct fertilizing, management, and irrigation practices are considered crucial to attenuate potential contamination of groundwater and suffosional sinkhole development in these areas.
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Vasil'chuk, Yurij Kirillovich, Jessica Yur'evna Vasil'chuk, and Alexander Pavlovich Ginzburg. "Cryogenic soils in the Vilyuy River Valley (Yakutia)." Арктика и Антарктика, no. 3 (March 2021): 80–107. http://dx.doi.org/10.7256/2453-8922.2021.3.36671.
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The object of this research is the cryogenic soils of the territory located in Central Yakutia, in the middle reach of Vilyuy River nearby Makhatta Tukulan with middle-taiga larch woods landscapes. In July 2021, on the right and left banks of the Vilyuy River, twelve soil sections have been formed, which relate to turf-podzols and turf-sub-units of the illovial-ferruginous, sod and alluvial sod, psammozems and stratozems according to to classification and diagnostics of Russian soils (2004). On the slope of the river valley was also formed the soil catena that included elementary geochemical landscapes of river terraces tops and slopes surfaces, as well as middle and high floodplains on the slopes of thermofusional funnels. Soil sections were also formed in flooded beam bottom and well-drained ravine bottom, on sub-horizontal Makhatta Tukulan surface, bottoms and slopes of thermo-suffosional funnels. The study involves 46 soil samples for measuring the acidity level (pH), electric conductivity (EC), and concentration of total disolved solids (TDS). The explored soils are characterized with pH ranging from 2.81 to 7.78, with most common fluctuations of 5.5–5.6. TDS rates were often within the limit of 10 mg L-1 and rarely exceeded that threshold, however, there were single valyes higher than 50 mg L-1. Thus, the highest EC values (over 100 μS/cm) were measured in surface and subsurface horizons with high organic matter content, whereas mostly mineral horizons had typical EС values within the limit of 20 μS/cm.
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Iwanek, Małgorzata, Paweł Suchorab, and Małgorzata Karpińska-Kiełbasa. "Suffosion Holes as the Results of a Breakage of a Buried Water Pipe." Periodica Polytechnica Civil Engineering, March 6, 2017. http://dx.doi.org/10.3311/ppci.9728.
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The result of a breakage of a buried water pipe is the watermovement in soil, which can cause that fine soil particles arewashed out from the solid matrix and transported through pores(suffosion process). It is widely known that the most hazardoussuffosion effects in urban areas relate to water-engineeringstructures. Holes, that can form on the soil surface by wateroutflowing after a failure of a buried pipeline (suffosion holes),are in different shapes and sizes. Recognition of factors influencingholes shapes and sizes would facilitate the preventionof hazardous suffosion effects connected with failures of waterdistribution systems. In the range of the presented article, theinfluence of selected parameters on the dimensions of suffosionholes was analyzed. The basis of the analysis was results oflaboratory investigations of the controlled leakage from a buriedwater pipe. The vast majority of values of suffosion holesareas, selected according to area of leak and hydraulic pressurehead in a pipe, occurred normally distributed. The tendencyof average area of suffosion holes to be higher with risingpressure head in a pipe was clearly visible, but we were asyet unable to select one regression model fitting measured andcalculated data better than others. Moreover, no tendency wasobserved between the biggest probable area of suffosion holeand pressure head in a pipe.
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Vetési-Foith, Szilárd. "Analysing the influencing factors of a postgenetic subsidence doline’s development using model experiments." Journal of Geological Research 2, no. 1 (July 2, 2020). http://dx.doi.org/10.30564/jgr.v2i1.1988.
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The subsidence dolines are the most common surface forms of the concealed karsts. One type of these dolines is the suffosion doline. In this model experiment the influential role of these kind of dolines’ development factors were analyzed. The aim of the study was to determine the significance of the parameters (cover thickness, secondary porosity of the bedrock, chimney diameter, grain size) that influence the development of a suffosion doline. To study the influencing factors numerous (162) experiments were made with different parameters, in a manner that during the experiments we changed only one parameter, so the effects of it would be detectable from the final solution. These measurements were made with the use of a special tool, designed and built for this purpose. According to the data we gained from the model experiments, the development of a suffosion doline is influenced by many parameters. If these parameters are in an optimal connection to each other, a suffosion doline may appear on the surface. Knowing these parameters of the covered karstic depressions lets us estimate other parameters that may influence the development of the subsidence dolines.
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Mihevc, Andrej, and Rok Mihevc. "Morphological characteristics and distribution of dolines in Slovenia, a study of a lidar-based doline map of Slovenia." Acta Carsologica 50, no. 1 (May 31, 2021). http://dx.doi.org/10.3986/ac.v50i1.9462.
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Dolines are small to intermediate enclosed depressions and are the most numerous karst feature in Slovenia. They are circular in plan form and vary in diameter from a few metres to over a kilometre. They are developed in limestone, dolomite, carbonate breccia and conglomerate and occupy different geomorphic settings. They were formed by various processes like dissolution, collapse, suffosion and transformation of caves to surface features by denudation. Publicly accessible lidar data, provided by a nationwide laser scanning project of Slovenia, was used for this study. To catalogue the dolines, we manually label a fraction of the digital elevation model (DEM) with a binary mask indicating if the area is a doline or not. We then train a slightly modified u-net, a type of machine learning algorithm, on the labelled territory. Using the trained algorithm, we infer the binary mask on the entire DEM. We convert the resulting mask into an ESRI Shapefile and manually verify the results. We note that the training and inference are error prone on types of relief that were less common in the training set (e.g., the relatively uncommon collapse dolines). We believe manual verification mitigates most of these errors, so the resulting map is a good basis for the doline study. We have made our georeferenced catalogue of dolines available at https://dolines.org/ (Mihevc & Mihevc 2021). Dolines are found in most of the karst areas, except mountains where they were eroded by glacial action or covered by glacial deposits. We detected 471,192 dolines and divided them into three genetic types. Most abundant are solution dolines (470,325). The average doline is 9 m deep, has a diameter of 42 m and a volume of 14,098 m3. The density of dolines on levelled surfaces can be as high as 500/ per km2. They are absent from the floors of poljes and steeper slopes, and are less abundant on sloping surfaces. We have identified 314 dolines to be of collapse origin. The mean depth of collapse dolines is 49 m, and 20 of them are deeper than 100 m. The mean volume is 1.2 million m3, with the largest having a volume of 11.6 million m3. Most of the collapse dolines can be found close to ponors or springs or corridors where large underground rivers flow. We have detected 553 suffosion dolines formed by suffosion of sediments in blind valleys or on poljes. This basic data set for dolines enables further study and comparison of dolines with the geology and topography of the karst.
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Strzałkowski, Piotr. "The influence of selected mining and natural factors on the sinkhole creation hazard based on the case study." Environmental Earth Sciences 80, no. 3 (February 2021). http://dx.doi.org/10.1007/s12665-021-09403-1.
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AbstractThe formation of sinkholes, especially in developed areas, constitutes a considerable hazard to the public safety. Due to the above, the subject of the paper is a significant and current issue. The paper includes a case study of sinkholes forming over shallow mine galleries. Calculations of the workings’ stability and the impact of the underground mining exploitation have been conducted. The probability of sinkhole formation has been determined as well. The time of sinkholes formation did not correspond with the time in which the mining exploitation affected the gallery workings and the moment in time for which the rock mass deformations caused by the exploitation were at the highest level. The performed exploitation caused occurrence of cracks in the rock mass over the working. This allowed the transportation of the loose overburden by rainwater to workings and as a result sinkholes were created—suffosion occurred. The Quaternary overburden built of sands and sandy loams was probably washed out by rainwater, which led to the formation of sinkholes. In all locations, where shallow voids exist at a depth up to 100 m and the overburden consists of loose rocks, one should consider the probability of sinkholes formation.
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Scheperboer, I. C., A. S. J. Suiker, E. Bosco, and F. H. L. R. Clemens. "A coupled hydro-mechanical model for subsurface erosion with analyses of soil piping and void formation." Acta Geotechnica, April 6, 2022. http://dx.doi.org/10.1007/s11440-022-01479-8.
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AbstractA coupled hydro-mechanical erosion model is presented that is used for studying soil piping and erosion void formation under practical, in-situ conditions. The continuum model treats the soil as a two-phase porous medium composed of a solid phase and a liquid phase, and accounts for its elasto-plastic deformation behaviour caused by frictional sliding and granular compaction. The kinetic law characterizing the erosion process is assumed to have a similar form as the type of threshold law typically used in interfacial erosion models. The numerical implementation of the coupled hydro-mechanical model is based on an incremental-iterative, staggered update scheme. A one-dimensional poro-elastic benchmark problem is used to study the basic features of the hydro-mechanical erosion model and validate its numerical implementation. This problem is further used to reveal the interplay between soil erosion and soil consolidation processes that occur under transient hydro-mechanical conditions, thereby identifying characteristic time scales of these processes for a sandy material. Subsequently, two practical case studies are considered that relate to a sewer system embedded in a sandy soil structure. The first case study treats soil piping caused by suffusion near a sewer system subjected to natural ground water flow, and the second case study considers the formation of a suffosion erosion void under strong ground water flow near a defect sewer pipe. The effects on the erosion profile and the soil deformation behaviour by plasticity phenomena are elucidated by comparing the computational results to those obtained by modelling the constitutive behaviour of the granular material as elastic. The results of this comparison study point out the importance of including an advanced elasto-plastic soil model in the numerical simulation of erosion-driven ground surface deformations and the consequent failure behaviour. The numerical analyses further illustrate that the model realistically predicts the size, location, and characteristic time scale of the generated soil piping and void erosion profiles. Hence, the modelling results may support the early detection of in-situ subsurface erosion phenomena from recorded ground surface deformations. Additionally, the computed erosion profiles may serve as input for a detailed analysis of the local, residual bearing capacity and stress redistribution of buried concrete pipe systems.