Debris flow events in the Blagoevgradska Bistritsa catchment (SW Bulgaria) become more frequent in the past few years. To localize the debris source along the tributary system, the Harsovska River is chosen in this study. During the observation period a torrential event was registered in June 2023. The synoptic situation, which caused the flood, is re-analyzed and also geomorphological research is made for depositional landforms in the river channel for the period 2019-2023. In the study, the alluvial sediments are defined by grain size and also by morphoscopic study of pebble-sized grains. During the field research, two critical flood-risk sites are pointed, located in the Harsovo hamlet. The data about past debris flow events are collected from residents of Harsovo with interviews regarding their experience in this issue. In the period of the study, the main part of debris nourishment in Harsovska catchment is provided by the tributary Marulevska River, where active mass movement processes are registered. However, the alluvial profiles of both rivers – Marulevska and Harsovska, showed an alternation of coarser and finer materials, resulting of turbulent and calm discharge. Such periodical change in the sedimentary environment of the two compound rivers demonstrates their unsteady torrential character. Regarding the fortification activities in this area, at the moment some new forestation has been noticed. Still, the species, used to fortify the river banks are not suitable for the climate and hydrological regime of the region. The channel fortifications, built in the middle of the 20th century, currently are not maintained properly, which puts under threat of future debris flow events the settlements and infrastructure along this catchment.
{"title":"Geomorphological study of the debris flow events in the Harsovska River (Blagoevgradska Bistritsa catchment), observed within 2019-2023","authors":"R. Kenderova, G. Rachev, A. Baltakova","doi":"10.52321/igh.38.1.53","DOIUrl":"https://doi.org/10.52321/igh.38.1.53","url":null,"abstract":"Debris flow events in the Blagoevgradska Bistritsa catchment (SW Bulgaria) become more frequent in the past few years. To localize the debris source along the tributary system, the Harsovska River is chosen in this study. During the observation period a torrential event was registered in June 2023. The synoptic situation, which caused the flood, is re-analyzed and also geomorphological research is made for depositional landforms in the river channel for the period 2019-2023. In the study, the alluvial sediments are defined by grain size and also by morphoscopic study of pebble-sized grains. During the field research, two critical flood-risk sites are pointed, located in the Harsovo hamlet. The data about past debris flow events are collected from residents of Harsovo with interviews regarding their experience in this issue. In the period of the study, the main part of debris nourishment in Harsovska catchment is provided by the tributary Marulevska River, where active mass movement processes are registered. However, the alluvial profiles of both rivers – Marulevska and Harsovska, showed an alternation of coarser and finer materials, resulting of turbulent and calm discharge. Such periodical change in the sedimentary environment of the two compound rivers demonstrates their unsteady torrential character. Regarding the fortification activities in this area, at the moment some new forestation has been noticed. Still, the species, used to fortify the river banks are not suitable for the climate and hydrological regime of the region. The channel fortifications, built in the middle of the 20th century, currently are not maintained properly, which puts under threat of future debris flow events the settlements and infrastructure along this catchment.","PeriodicalId":512391,"journal":{"name":"Engineering Geology and Hydrogeology","volume":"23 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141020145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study is related to the preparation of a project for the construction of a fishing port for small vessels in the area between the mouth of the Dyavolska River and Cape Kyupria (SE Bulgaria) with the aim of protecting the water area from dangerous wave loads, geological and meteorological impacts and creating conditions for safe docking, service and accommodation of the fishing vessels. The geological structure, geomorphology and physical-geological phenomena in the water area of Primorsko Fishing Port in the southern part of Cape Kyupria have been clarified. An engineering-geological project was prepared, the physico-mechanical indicators of the construction soils and the geotechnical characteristics of the ground base were determined. A complex package of scientific and engineering-geological methods was applied during the implementation of the project. Based on the obtained scientific and applied results, recommendations were made to the Municipality of Primorsko in connection with the construction of the port. The foundation conditions of the designed wharf with a walled pier are favorable for the construction of the wharf with gravity hydrotechnical facilities.
{"title":"Engineering Geological and Hydrotechnical Conditions of Primorsko Fishing Port, SE Bulgaria","authors":"Dimitar Dimitrov, Gencho Georgiev","doi":"10.52321/igh.38.1.37","DOIUrl":"https://doi.org/10.52321/igh.38.1.37","url":null,"abstract":"The present study is related to the preparation of a project for the construction of a fishing port for small vessels in the area between the mouth of the Dyavolska River and Cape Kyupria (SE Bulgaria) with the aim of protecting the water area from dangerous wave loads, geological and meteorological impacts and creating conditions for safe docking, service and accommodation of the fishing vessels. The geological structure, geomorphology and physical-geological phenomena in the water area of Primorsko Fishing Port in the southern part of Cape Kyupria have been clarified. An engineering-geological project was prepared, the physico-mechanical indicators of the construction soils and the geotechnical characteristics of the ground base were determined. A complex package of scientific and engineering-geological methods was applied during the implementation of the project. Based on the obtained scientific and applied results, recommendations were made to the Municipality of Primorsko in connection with the construction of the port. The foundation conditions of the designed wharf with a walled pier are favorable for the construction of the wharf with gravity hydrotechnical facilities.","PeriodicalId":512391,"journal":{"name":"Engineering Geology and Hydrogeology","volume":"14 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141020059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper is focused on the testing of material from the "Lyulyakovitsa" tailings dam situated in proximity to the town of Panagyurishte in Bulgaria. The primary objective of this study is to investigate various laboratory techniques aimed at determining essential dynamic characteristics of the studied material. This research is conducted with the goal of subsequently assessing the seismic response of the existing tailings dam. In the context of performing an equivalent linear analysis, a widely used approach in geotechnical earthquake engineering, several crucial relationships and parameters come into play. These include the material's stiffness degradation, the damping ratio, and the small-strain stiffness, expressed through the shear wave velocity. The paper describes analysis of three experiments carried out in the geotechnical laboratory "Komaba" at the University of Tokyo. These experiments introduce undrained cyclic triaxial tests conducted under identical relative density (95%) of the tailings and executed at 50 kPa, 80 kPa, and 100 kPa effective confining stress, specifically, respectively. Additionally, two distinct testing methods were employed to measure the shear wave velocity in the specimens. The findings align with certain established directions in the existing literature for characterizing the dynamic properties of granular soils. Simultaneously, they underscore the practicality of the laboratory experiments adopted for acquiring a comprehensive set of relationships and parameters.
{"title":"Experimental evaluation of dynamic geotechnical parameters of tailings","authors":"Nikolay Milev, Junichi Koseki","doi":"10.52321/igh.38.1.3","DOIUrl":"https://doi.org/10.52321/igh.38.1.3","url":null,"abstract":"The paper is focused on the testing of material from the \"Lyulyakovitsa\" tailings dam situated in proximity to the town of Panagyurishte in Bulgaria. The primary objective of this study is to investigate various laboratory techniques aimed at determining essential dynamic characteristics of the studied material. This research is conducted with the goal of subsequently assessing the seismic response of the existing tailings dam. In the context of performing an equivalent linear analysis, a widely used approach in geotechnical earthquake engineering, several crucial relationships and parameters come into play. These include the material's stiffness degradation, the damping ratio, and the small-strain stiffness, expressed through the shear wave velocity. The paper describes analysis of three experiments carried out in the geotechnical laboratory \"Komaba\" at the University of Tokyo. These experiments introduce undrained cyclic triaxial tests conducted under identical relative density (95%) of the tailings and executed at 50 kPa, 80 kPa, and 100 kPa effective confining stress, specifically, respectively. Additionally, two distinct testing methods were employed to measure the shear wave velocity in the specimens. The findings align with certain established directions in the existing literature for characterizing the dynamic properties of granular soils. Simultaneously, they underscore the practicality of the laboratory experiments adopted for acquiring a comprehensive set of relationships and parameters.","PeriodicalId":512391,"journal":{"name":"Engineering Geology and Hydrogeology","volume":"1 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141021416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the context of Bulgaria's expanding construction sector, the northern region of the Danube Plain has encountered challenges associated with the subsidence of loess soils upon saturation, characterized by rapid settlement and self-compaction – also known as “collapse”. This phenomenon poses significant risks to construction projects, prompting extensive research into its causes and prevention. One widely adopted method for stabilizing loess soil foundations in construction is the use of cement-soil cushions (CSC). This study's primary objective is to explore and select an effective technology for constructing a suitable composition of a cement-soil (loess-cement) cushion beneath buildings’ foundations in Kozloduy, where the soil is collapsible loess.
{"title":"Studying the mechanical behavior of loess-cement mixtures and adopting a cement-soil cushion (CSC) as a shallow ground improvement solution for foundations laying on collapsible soils","authors":"Nikolay Milev, Ivailo Ivanov","doi":"10.52321/igh.38.1.17","DOIUrl":"https://doi.org/10.52321/igh.38.1.17","url":null,"abstract":"In the context of Bulgaria's expanding construction sector, the northern region of the Danube Plain has encountered challenges associated with the subsidence of loess soils upon saturation, characterized by rapid settlement and self-compaction – also known as “collapse”. This phenomenon poses significant risks to construction projects, prompting extensive research into its causes and prevention. One widely adopted method for stabilizing loess soil foundations in construction is the use of cement-soil cushions (CSC). This study's primary objective is to explore and select an effective technology for constructing a suitable composition of a cement-soil (loess-cement) cushion beneath buildings’ foundations in Kozloduy, where the soil is collapsible loess.","PeriodicalId":512391,"journal":{"name":"Engineering Geology and Hydrogeology","volume":"24 55","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141019815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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