{"title":"Peculiarities of the materials involved in the debris flows in Kresna Gorge, Southwest Bulgaria","authors":"N. Dobrev, P. Ivanov, A. Baltakova, R. Rizova","doi":"10.52321/igh.37.1.19","DOIUrl":null,"url":null,"abstract":"Debris flow events periodically occur in the northern part of the Kresna Gorge, SW Bulgaria. Most of them damage the infrastructure and block the traffic along the National Route E79. In the present paper, we analyze the physical properties of the materials involved in debris flow transportation and sedimentation. Samples taken from events in 2017 and 2021 were studied. Plasticity properties were found in the materials deposited in and near the alluvial fan. The plasticity index is up to 23.4% according to BDS EN ISO 17892-12. The particle size composition of the samples shows a predominance of gravelly sand and sandy gravel materials according to the BDS EN ISO 14688-2 standard. The samples taken from the transport zone are defined as gravel and less commonly as sandy gravel. The sand content in them is lower – from 5.3 to 48.5% (average 21.5%) than in the samples taken from the source area and accumulation zone, where the average values are 43.8% and 47.4%, respectively. In the accumulation zone, the quantity of sand content also increases – the average value is 14.1%, while in the source and transport zones it is 6.6% and 8.2%, respectively. The debris flows materials are polydisperse, with dominantly angular and subangular roundness. The coarser grains are accumulated within the stream channel. The finer grains (silty and clayey) are more common in the periphery of the accumulation zone (alluvial fan).","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":"7 1","pages":""},"PeriodicalIF":1.3000,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Quarterly Journal of Engineering Geology and Hydrogeology","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.52321/igh.37.1.19","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENGINEERING, GEOLOGICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Debris flow events periodically occur in the northern part of the Kresna Gorge, SW Bulgaria. Most of them damage the infrastructure and block the traffic along the National Route E79. In the present paper, we analyze the physical properties of the materials involved in debris flow transportation and sedimentation. Samples taken from events in 2017 and 2021 were studied. Plasticity properties were found in the materials deposited in and near the alluvial fan. The plasticity index is up to 23.4% according to BDS EN ISO 17892-12. The particle size composition of the samples shows a predominance of gravelly sand and sandy gravel materials according to the BDS EN ISO 14688-2 standard. The samples taken from the transport zone are defined as gravel and less commonly as sandy gravel. The sand content in them is lower – from 5.3 to 48.5% (average 21.5%) than in the samples taken from the source area and accumulation zone, where the average values are 43.8% and 47.4%, respectively. In the accumulation zone, the quantity of sand content also increases – the average value is 14.1%, while in the source and transport zones it is 6.6% and 8.2%, respectively. The debris flows materials are polydisperse, with dominantly angular and subangular roundness. The coarser grains are accumulated within the stream channel. The finer grains (silty and clayey) are more common in the periphery of the accumulation zone (alluvial fan).
泥石流事件周期性地发生在保加利亚西南部的克雷斯纳峡谷北部。其中大多数破坏了基础设施,阻塞了E79国道沿线的交通。在本文中,我们分析了参与泥石流运输和沉积的物质的物理性质。研究人员研究了2017年和2021年事件中采集的样本。冲积扇内及附近沉积的物质具有可塑性。根据BDS EN ISO 17892-12,塑性指数可达23.4%。根据BDS EN ISO 14688-2标准,样品的粒度组成以砾石砂和砂砾石材料为主。从运输带取的样品被定义为砾石,较少被定义为砂砾石。其中含砂量为5.3% ~ 48.5%,平均21.5%,低于源区和堆积区的平均值43.8%和47.4%。堆积区含砂量也增加,平均为14.1%,源区和输运区分别为6.6%和8.2%。泥石流物质多分散,以角圆度和次角圆度为主。较粗的颗粒积聚在河道内。较细颗粒(粉质和粘土)在堆积带外围(冲积扇)较为常见。
期刊介绍:
Quarterly Journal of Engineering Geology and Hydrogeology is owned by the Geological Society of London and published by the Geological Society Publishing House.
Quarterly Journal of Engineering Geology & Hydrogeology (QJEGH) is an established peer reviewed international journal featuring papers on geology as applied to civil engineering mining practice and water resources. Papers are invited from, and about, all areas of the world on engineering geology and hydrogeology topics. This includes but is not limited to: applied geophysics, engineering geomorphology, environmental geology, hydrogeology, groundwater quality, ground source heat, contaminated land, waste management, land use planning, geotechnics, rock mechanics, geomaterials and geological hazards.
The journal publishes the prestigious Glossop and Ineson lectures, research papers, case studies, review articles, technical notes, photographic features, thematic sets, discussion papers, editorial opinion and book reviews.