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。
{"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":"https://doi.org/10.52321/igh.37.1.19","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":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79805043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhongbai Liu, Tao Zhou, Lei Huang, Xinguang Cheng, Zhen-en Huang
Many tunnels are inevitably built near valley terrain, which greatly amplifies the seismic response of the tunnel. This paper considers the interaction between valley terrain and tunnels, proposes a high-precision indirect boundary element method (IBEM) for simulation, and verifies the correctness of the method. The impact of factors such as incident wave type, incident frequency, and distance between the tunnel and the valley on the seismic response of the tunnel is then analyzed in detail. The numerical analysis demonstrates that the stress of the tunnel can be amplified by approximately twice when the distance between the river valley and the tunnel is 10m due to the scattering and coherence effects of seismic waves. However, when this distance is greater than 50m, the presence of river valleys has little effect on the stress of the tunnel. The stress at the right shoulder of the tunnel and the displacement amplification effect on the valley slope is significant compared to other areas. The findings of this study provide theoretical guidance for the seismic fortification and disaster avoidance of tunnel structures near river valleys.
{"title":"The amplification effect of river valley topography on seismic response of a tunnel near the valley: simulated by boundary element method","authors":"Zhongbai Liu, Tao Zhou, Lei Huang, Xinguang Cheng, Zhen-en Huang","doi":"10.1144/qjegh2022-142","DOIUrl":"https://doi.org/10.1144/qjegh2022-142","url":null,"abstract":"Many tunnels are inevitably built near valley terrain, which greatly amplifies the seismic response of the tunnel. This paper considers the interaction between valley terrain and tunnels, proposes a high-precision indirect boundary element method (IBEM) for simulation, and verifies the correctness of the method. The impact of factors such as incident wave type, incident frequency, and distance between the tunnel and the valley on the seismic response of the tunnel is then analyzed in detail. The numerical analysis demonstrates that the stress of the tunnel can be amplified by approximately twice when the distance between the river valley and the tunnel is 10m due to the scattering and coherence effects of seismic waves. However, when this distance is greater than 50m, the presence of river valleys has little effect on the stress of the tunnel. The stress at the right shoulder of the tunnel and the displacement amplification effect on the valley slope is significant compared to other areas. The findings of this study provide theoretical guidance for the seismic fortification and disaster avoidance of tunnel structures near river valleys.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45336230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Landslides often occur along expressways in earthquake-prone areas, leading to casualties and property loss. Most previous studies applied the simplified Newmark method to assess landslide susceptibility at a regional scale, ignoring the characteristics of local ground motions. In this study, we investigated permanent displacement characteristics of three potential landslide areas along the Dayong expressway using the rigorous Newmark method, considering the frequency and energy characteristics of the historical seismic waves. First, we analyzed the frequency characteristics of historical earthquakes in the study areas using the fast Fourier transform method and adopted them as input ground motions in calculating the Newmark displacement. Next, we computed the critical accelerations of the three study areas. Parameters such as the elevation, soil layer thickness, and soil strength required for critical acceleration calculations were obtained using high-precision (approximately 3 cm) unmanned aerial vehicle mapping technology, drilling operations, and laboratory tests. Finally, the Newmark displacement was calculated, and landslide susceptibility of the study areas was evaluated. The results showed that the predominant frequency of historical seismic waves in the study areas was 0.38–3.36 Hz, indicating low-frequency characteristics. The results also indicated that the frequency and energy characteristics of the seismic ground motions significantly influenced the Newmark displacement. The maximum Newmark displacement under different waveforms at Damieju ranged from 2 to 18 cm. Under the most dangerous conditions, all three areas showed potential for landslides. The maximum Newmark displacement positively correlated with the energy of the predominant frequency. Large energy and low frequency characteristics of seismic wave corresponds to a large displacement. The simplified Newmark method in regional landslide susceptibility analysis did not reflect this effect and may be unsuitable to determine the size of landslides.
{"title":"Permanent displacement characteristics of landslide considering frequency and energy behaviors of historical seismic ground motions","authors":"Hua Tang, Yuwei Fang, Xu Cheng, Zhenjun Wu, Yu Qin","doi":"10.1144/qjegh2022-062","DOIUrl":"https://doi.org/10.1144/qjegh2022-062","url":null,"abstract":"Landslides often occur along expressways in earthquake-prone areas, leading to casualties and property loss. Most previous studies applied the simplified Newmark method to assess landslide susceptibility at a regional scale, ignoring the characteristics of local ground motions. In this study, we investigated permanent displacement characteristics of three potential landslide areas along the Dayong expressway using the rigorous Newmark method, considering the frequency and energy characteristics of the historical seismic waves. First, we analyzed the frequency characteristics of historical earthquakes in the study areas using the fast Fourier transform method and adopted them as input ground motions in calculating the Newmark displacement. Next, we computed the critical accelerations of the three study areas. Parameters such as the elevation, soil layer thickness, and soil strength required for critical acceleration calculations were obtained using high-precision (approximately 3 cm) unmanned aerial vehicle mapping technology, drilling operations, and laboratory tests. Finally, the Newmark displacement was calculated, and landslide susceptibility of the study areas was evaluated. The results showed that the predominant frequency of historical seismic waves in the study areas was 0.38–3.36 Hz, indicating low-frequency characteristics. The results also indicated that the frequency and energy characteristics of the seismic ground motions significantly influenced the Newmark displacement. The maximum Newmark displacement under different waveforms at Damieju ranged from 2 to 18 cm. Under the most dangerous conditions, all three areas showed potential for landslides. The maximum Newmark displacement positively correlated with the energy of the predominant frequency. Large energy and low frequency characteristics of seismic wave corresponds to a large displacement. The simplified Newmark method in regional landslide susceptibility analysis did not reflect this effect and may be unsuitable to determine the size of landslides.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48962264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
While the Lugeon test was initially designed to aid in determining the grouting needs of dam foundations in fractured rock, its outcomes have been utilised by geotechnical engineers and hydrogeologists to estimate the hydraulic conductivity. Most of the practitioners use the long-established relation of 1 Lu ≈ 1 e − 7 m/s to calculate the hydraulic conductivity based on the determined Lugeon value. However, this relationship does not cover all the potential boundary conditions encountered in field conditions where the Lugeon test is applied and the consequences on the estimated hydraulic conductivity are poorly understood. This paper aims to address this issue by revisiting existing mathematical formulations to calculate the hydraulic conductivity from the Lugeon test under the various boundary conditions. The paper also examines how the flow conditions and length of test intervals impact the recorded Lu and hydraulic conductivity values. It was found that the long-stablished relationship of 1 Lu ≈ 1 e − 7 m/s and the equation presented in the commonly used reference of BS5930:2010 only present one of the potential boundary conditions for Lugeon test.
{"title":"Lugeon Test: New insights Into the Calculated Hydraulic Conductivity","authors":"M. Zoorabadi","doi":"10.1144/qjegh2023-006","DOIUrl":"https://doi.org/10.1144/qjegh2023-006","url":null,"abstract":"\u0000 While the Lugeon test was initially designed to aid in determining the grouting needs of dam foundations in fractured rock, its outcomes have been utilised by geotechnical engineers and hydrogeologists to estimate the hydraulic conductivity. Most of the practitioners use the long-established relation of 1\u0000 Lu\u0000 ≈ 1\u0000 e\u0000 − 7\u0000 m/s\u0000 to calculate the hydraulic conductivity based on the determined Lugeon value. However, this relationship does not cover all the potential boundary conditions encountered in field conditions where the Lugeon test is applied and the consequences on the estimated hydraulic conductivity are poorly understood. This paper aims to address this issue by revisiting existing mathematical formulations to calculate the hydraulic conductivity from the Lugeon test under the various boundary conditions. The paper also examines how the flow conditions and length of test intervals impact the recorded\u0000 Lu\u0000 and hydraulic conductivity values. It was found that the long-stablished relationship of 1\u0000 Lu\u0000 ≈ 1\u0000 e\u0000 − 7\u0000 m/s\u0000 and the equation presented in the commonly used reference of BS5930:2010 only present one of the potential boundary conditions for Lugeon test.\u0000","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48469737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Bianchi, S. Collins, J. Ford, O. Wakefield, J. Dearlove, M. Swartz, A. Hughes
Groundwater abstractions from the Carboniferous Fell Sandstone, Northumbria, north-east England, provide water supply to the Berwick-upon-Tweed area. Management of these abstractions, totalling 6.5 Ml/day, by the water company along with the regulator for sustainability issues is required. Groundwater abstraction takes place from different sandstone units, which are separated by mudstones, with monitored groundwater heads showing variable responses to system stresses. To improve understanding of this complex system, various activities have been undertaken. Geological mapping and interpretation have been conducted to characterise the nature, geometry, and interconnection of the sandstone units, along with the superficial deposits. Recharge modelling has used to quantify inputs to the system and to understand the long-term water balance. A time-variant model has been implemented to simulate groundwater flow in the sandstone units and to quantify the groundwater balance. The work confirms that the Fell can be split into seven discrete sandstone units, separated by low permeability mudstones, but they are not necessarily laterally connected. There is a range of timescales of groundwater response to recharge events from slow (six months) to very rapid (∼1 day). These findings confirm the complexity of this groundwater system and offer lessons for similar sandstone systems in the UK and worldwide. Thematic collection: This article is part of the Hydrogeology of Sandstone collection available at: https://www.lyellcollection.org/cc/hydrogeology-of-sandstone
{"title":"Using numerical modelling to test the geological and groundwater conceptual understanding of a complex, layered aquifer: A case study from the Fell Sandstone, Northumbria","authors":"M. Bianchi, S. Collins, J. Ford, O. Wakefield, J. Dearlove, M. Swartz, A. Hughes","doi":"10.1144/qjegh2022-077","DOIUrl":"https://doi.org/10.1144/qjegh2022-077","url":null,"abstract":"Groundwater abstractions from the Carboniferous Fell Sandstone, Northumbria, north-east England, provide water supply to the Berwick-upon-Tweed area. Management of these abstractions, totalling 6.5 Ml/day, by the water company along with the regulator for sustainability issues is required. Groundwater abstraction takes place from different sandstone units, which are separated by mudstones, with monitored groundwater heads showing variable responses to system stresses. To improve understanding of this complex system, various activities have been undertaken. Geological mapping and interpretation have been conducted to characterise the nature, geometry, and interconnection of the sandstone units, along with the superficial deposits. Recharge modelling has used to quantify inputs to the system and to understand the long-term water balance. A time-variant model has been implemented to simulate groundwater flow in the sandstone units and to quantify the groundwater balance. The work confirms that the Fell can be split into seven discrete sandstone units, separated by low permeability mudstones, but they are not necessarily laterally connected. There is a range of timescales of groundwater response to recharge events from slow (six months) to very rapid (∼1 day). These findings confirm the complexity of this groundwater system and offer lessons for similar sandstone systems in the UK and worldwide. Thematic collection: This article is part of the Hydrogeology of Sandstone collection available at: https://www.lyellcollection.org/cc/hydrogeology-of-sandstone","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45318607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article presents the assessment results of the long-term annual average groundwater recharge for the territory of the Tundzha River catchment area. In order to assess those results, a GIS-method has been applied based on spatial analysis of the slope of the relief, soil cover and aquifer properties. A series of maps is presented and a quantitative analysis of the results obtained is carried out. The mean annual groundwater recharge ranges from 4 to 483 mm, or about 55 mm on average for the catchment area. Additional calculations have been made for water management purposes. For individual groundwater bodies that fall into the catchment area of the Tundzha River (managed primarily by the East Aegean River Basin Directorate) both groundwater recharge and their natural groundwater resources were assessed (based on the outcrop areas of the respective bodies).
{"title":"Groundwater Recharge and Resources in the Tundzha River Basin, Southeast Bulgaria","authors":"Tanya Vasileva","doi":"10.52321/igh.37.1.3","DOIUrl":"https://doi.org/10.52321/igh.37.1.3","url":null,"abstract":"This article presents the assessment results of the long-term annual average groundwater recharge for the territory of the Tundzha River catchment area. In order to assess those results, a GIS-method has been applied based on spatial analysis of the slope of the relief, soil cover and aquifer properties. A series of maps is presented and a quantitative analysis of the results obtained is carried out. The mean annual groundwater recharge ranges from 4 to 483 mm, or about 55 mm on average for the catchment area. Additional calculations have been made for water management purposes. For individual groundwater bodies that fall into the catchment area of the Tundzha River (managed primarily by the East Aegean River Basin Directorate) both groundwater recharge and their natural groundwater resources were assessed (based on the outcrop areas of the respective bodies).","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75347002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Dong, Z. Duan, Renwei Li, Jiang Li, Heng Li, Nianqin Wang, Jian-bing Peng, Xin Chen
The impact liquefaction of sediments in the path of a landslide would reduce the friction of sliding surface, leading to increase in the speed and distance of the landslide. In this study, a self-designed impact-liquefaction test was used to explore the pressure development of soil under the effect of different impact energies. The microscopic mechanisms were unravelled by using Nuclear Magnetic Resonance (NMR) and Scanning Electron Microscope (SEM) methods. The results show that the soil at the middle depth shows higher pore water pressure than at the top and bottom of the layer. Furthermore, the variation of pore water pressure in these parts is relatively stable, and the peak pressure linearly increases with impact energy. The collapse of large pores in sandy silt is the primary reason for the generation of high pore water pressures in sandy silt. But when the soils are high-energy impacted, the mesopores and small-pores are compressed and blocked, which also stimulate the pore water pressure. The result also demonstrates weak drainage behaviour of sandy silt under rapid impacting. If the impact energy is sufficient, the pore water pressure in sandy silt suppresses the dissipation, causing quick liquefaction in the interior of the sandy silt. Supplementary material: https://doi.org/10.6084/m9.figshare.c.6655482
{"title":"Impact liquefaction mechanism of sandy silt under energy change","authors":"C. Dong, Z. Duan, Renwei Li, Jiang Li, Heng Li, Nianqin Wang, Jian-bing Peng, Xin Chen","doi":"10.1144/qjegh2022-122","DOIUrl":"https://doi.org/10.1144/qjegh2022-122","url":null,"abstract":"The impact liquefaction of sediments in the path of a landslide would reduce the friction of sliding surface, leading to increase in the speed and distance of the landslide. In this study, a self-designed impact-liquefaction test was used to explore the pressure development of soil under the effect of different impact energies. The microscopic mechanisms were unravelled by using Nuclear Magnetic Resonance (NMR) and Scanning Electron Microscope (SEM) methods. The results show that the soil at the middle depth shows higher pore water pressure than at the top and bottom of the layer. Furthermore, the variation of pore water pressure in these parts is relatively stable, and the peak pressure linearly increases with impact energy. The collapse of large pores in sandy silt is the primary reason for the generation of high pore water pressures in sandy silt. But when the soils are high-energy impacted, the mesopores and small-pores are compressed and blocked, which also stimulate the pore water pressure. The result also demonstrates weak drainage behaviour of sandy silt under rapid impacting. If the impact energy is sufficient, the pore water pressure in sandy silt suppresses the dissipation, causing quick liquefaction in the interior of the sandy silt.\u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.6655482\u0000","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48272782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tom M. Statham, Richard Sumner, A. F. Hill, Jonathan W. N. Smith
Natural source zone depletion (NSZD) is increasingly being considered as a risk-management option at sites impacted with light non-aqueous phase liquids (LNAPL). NSZD can be applied in isolation or in combination with active remediation techniques, depending on site-specific risk management requirements. A case study of the transition from active remediation to passive NSZD is presented for a petroleum impacted site in northwest Europe. This transition was supported by multiple lines of evidence/management options including: the introduction of institutional controls on groundwater and land development restrictions, the results from a residual-NAPL risk assessment, monitoring to establish that the LNAPL plume is reducing in size, LNAPL transmissivity assessment, a CO2 equivalent assessment of remediation options, and a LNAPL recovery diminishing returns model. Through application of local sustainable remediation principles consistent with ISO / SuRF-UK sustainable remediation frameworks and tools, regulatory approval was obtained for a partial closeout of the remediation system. By the final year of operation, NSZD rates in the portion of the site on which transition to NSZD has been agreed were over three times greater than active LNAPL recovery rates (12,000 L/ha/a for NSZD; 3,800 L/ha/a for active LNAPL recovery). At the remaining active remediation areas total fluids extraction currently out-performs NSZD and will be continued until a comparable point is reached when NSZD removal exceeds active remediation. At that point transition to NSZD alone will be considered as the most sustainable risk-based approach.
{"title":"Transition from active remediation to natural source zone depletion (NSZD) at a LNAPL-impacted site, supported by sustainable remediation appraisal","authors":"Tom M. Statham, Richard Sumner, A. F. Hill, Jonathan W. N. Smith","doi":"10.1144/qjegh2022-140","DOIUrl":"https://doi.org/10.1144/qjegh2022-140","url":null,"abstract":"Natural source zone depletion (NSZD) is increasingly being considered as a risk-management option at sites impacted with light non-aqueous phase liquids (LNAPL). NSZD can be applied in isolation or in combination with active remediation techniques, depending on site-specific risk management requirements. A case study of the transition from active remediation to passive NSZD is presented for a petroleum impacted site in northwest Europe. This transition was supported by multiple lines of evidence/management options including: the introduction of institutional controls on groundwater and land development restrictions, the results from a residual-NAPL risk assessment, monitoring to establish that the LNAPL plume is reducing in size, LNAPL transmissivity assessment, a CO2 equivalent assessment of remediation options, and a LNAPL recovery diminishing returns model. Through application of local sustainable remediation principles consistent with ISO / SuRF-UK sustainable remediation frameworks and tools, regulatory approval was obtained for a partial closeout of the remediation system. By the final year of operation, NSZD rates in the portion of the site on which transition to NSZD has been agreed were over three times greater than active LNAPL recovery rates (12,000 L/ha/a for NSZD; 3,800 L/ha/a for active LNAPL recovery). At the remaining active remediation areas total fluids extraction currently out-performs NSZD and will be continued until a comparable point is reached when NSZD removal exceeds active remediation. At that point transition to NSZD alone will be considered as the most sustainable risk-based approach.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48100210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The UK road network is deteriorating due to ageing infrastructure, climate change and increasing traffic. Due to community and economic reliance on a functioning road system, there is an urgent requirement to build resilience. The roads of south Lincolnshire have high susceptibility to ground movement due to the underlying geology. Deposits such as peat, tidal flat deposits, and alluvium have a high susceptibility to compress, particularly when loaded, or through loss of water content driven by climate change or lowering of water in drainage channels. The shallow foundations of Lincolnshire's rural evolved roads, originating from old mud tracks, are poorly constructed, increasing their vulnerability to movement. Types of damage include longitudinal cracking, edge failure, and uneven long section profiles. Through knowledge exchange, data sharing and collaboration between the British Geological Survey and Lincolnshire County Council, a direct relationship between road condition and geohazard susceptibility has been demonstrated; showing compressible ground has a greater correlation with road damage than originally considered. This suggests improved understanding of the relationships between the geological, climatic, and anthropogenic driving forces on ground movement and road damage enables more informed repair prioritisation, decision support, and improved bespoke road repair practices, increasing future resilience of road networks. Thematic collection: This article is part of the Climate change and resilience in Engineering Geology and Hydrogeology collection available at: https://www.lyellcollection.org/topic/collections/climate-change-and-resilience-in-engineering-geology-and-hydrogeology
{"title":"Increasing road network resilience to the impacts of ground movement due to climate change – A case study from Lincolnshire, United Kingdom","authors":"A. Harrison, M. Heaton, D. Entwisle","doi":"10.1144/qjegh2023-002","DOIUrl":"https://doi.org/10.1144/qjegh2023-002","url":null,"abstract":"The UK road network is deteriorating due to ageing infrastructure, climate change and increasing traffic. Due to community and economic reliance on a functioning road system, there is an urgent requirement to build resilience. The roads of south Lincolnshire have high susceptibility to ground movement due to the underlying geology. Deposits such as peat, tidal flat deposits, and alluvium have a high susceptibility to compress, particularly when loaded, or through loss of water content driven by climate change or lowering of water in drainage channels. The shallow foundations of Lincolnshire's rural evolved roads, originating from old mud tracks, are poorly constructed, increasing their vulnerability to movement. Types of damage include longitudinal cracking, edge failure, and uneven long section profiles. Through knowledge exchange, data sharing and collaboration between the British Geological Survey and Lincolnshire County Council, a direct relationship between road condition and geohazard susceptibility has been demonstrated; showing compressible ground has a greater correlation with road damage than originally considered. This suggests improved understanding of the relationships between the geological, climatic, and anthropogenic driving forces on ground movement and road damage enables more informed repair prioritisation, decision support, and improved bespoke road repair practices, increasing future resilience of road networks.\u0000 \u0000 Thematic collection:\u0000 This article is part of the Climate change and resilience in Engineering Geology and Hydrogeology collection available at:\u0000 https://www.lyellcollection.org/topic/collections/climate-change-and-resilience-in-engineering-geology-and-hydrogeology\u0000","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47994127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anisotropy affects the mechanical behaviours of rock, especially for application in rock engineering. In this study, a digital drilling method is proposed to evaluate the mechanical anisotropy of rock. In consideration with the critical friction, the cutting efficiency and contact stress are determined from the revised drilling model to characterize the drilling process. For six types of rock, a series of drilling tests are conducted on three axial directions using the coring bit. The anisotropy of rock strength is obtained from the point load test to compare with the anisotropy of drilling characteristics. Correspondingly, an anisotropy criterion is established. A critical point is identified in the evolution of contact stress and the plot of drilling parameters, corresponding to the critical friction. Result indicates that the evolution of contact stress with inclination angle suggests the similar elastic and plastic stages (inclination angles of 5 and 12, respectively). The typical evolution is also confirmed by the critical depth of the friction point. Moreover, the cutting efficiency and contact stress at the critical point show the evident anisotropic characteristic. A comparison of A 1 and A 2 is conducted to determine the anisotropy index of drilling characteristics. Contact stress present the anisotropy sequence as shale (22.45) > gneiss (14.21) > schist 302 (10.74) and blue sandstone (10.07) > granite (7.29) > red sandstone (5.09). The consistency examination with strength anisotropy index suggests that the contact stress has a fitting correlation with an accuracy of 91 %. In summary, the digital drilling-based method provides a reliable evaluation for rock anisotropy, showing potential in practical application.
{"title":"Digital drilling-based determination of rock anisotropy and anisotropic effect on cutter wear","authors":"Haoteng Wang, Mingming He, Jian-bin Zhao, Yonghao Zhang","doi":"10.1144/qjegh2022-103","DOIUrl":"https://doi.org/10.1144/qjegh2022-103","url":null,"abstract":"\u0000 Anisotropy affects the mechanical behaviours of rock, especially for application in rock engineering. In this study, a digital drilling method is proposed to evaluate the mechanical anisotropy of rock. In consideration with the critical friction, the cutting efficiency and contact stress are determined from the revised drilling model to characterize the drilling process. For six types of rock, a series of drilling tests are conducted on three axial directions using the coring bit. The anisotropy of rock strength is obtained from the point load test to compare with the anisotropy of drilling characteristics. Correspondingly, an anisotropy criterion is established. A critical point is identified in the evolution of contact stress and the plot of drilling parameters, corresponding to the critical friction. Result indicates that the evolution of contact stress with inclination angle suggests the similar elastic and plastic stages (inclination angles of 5 and 12, respectively). The typical evolution is also confirmed by the critical depth of the friction point. Moreover, the cutting efficiency and contact stress at the critical point show the evident anisotropic characteristic. A comparison of\u0000 A\u0000 1\u0000 and\u0000 A\u0000 2\u0000 is conducted to determine the anisotropy index of drilling characteristics. Contact stress present the anisotropy sequence as shale (22.45) > gneiss (14.21) > schist 302 (10.74) and blue sandstone (10.07) > granite (7.29) > red sandstone (5.09). The consistency examination with strength anisotropy index suggests that the contact stress has a fitting correlation with an accuracy of 91 %. In summary, the digital drilling-based method provides a reliable evaluation for rock anisotropy, showing potential in practical application.\u0000","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44699874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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