Rock mass erosion in unlined spillways causes significant structural damage and necessitates expensive repairs. The rock mass is made up of blocks formed by various arrangements of joint sets. The volume and the protrusion of these blocks, as well as the orientation, opening and roughness of the joints, are all features that can affect rock erodibility. Most of these features are incorporated in parameters developed for rock mass characterization. Three joint orientation parameters are compared in this article using a database containing geological and hydraulic information on scoured spillways. According to the detailed methodology, data is first classified according to rock quality using the GSI chart index. Then, for each GSI chart class, data is distributed according to the damage level, stream power and joint orientation parameter chosen. This study shows that no joint orientation parameter is currently able to accurately represent the effect of joint orientation on erosion of excellent- to poor-quality rock mass. Moreover, this study shows that the GSI chart index is not a rock quality index that completely evaluates rock erosion, since some relevant parameters for evaluating rock erodibility are not considered.
{"title":"Comparison of Existing Joint Orientation Parameters and Their Effect on Rock Erodibility in Dam Spillways","authors":"Marie-Hélène Wisse, A. Saeidi, M. Quirion","doi":"10.1144/qjegh2022-042","DOIUrl":"https://doi.org/10.1144/qjegh2022-042","url":null,"abstract":"\u0000 Rock mass erosion in unlined spillways causes significant structural damage and necessitates expensive repairs. The rock mass is made up of blocks formed by various arrangements of joint sets. The volume and the protrusion of these blocks, as well as the orientation, opening and roughness of the joints, are all features that can affect rock erodibility. Most of these features are incorporated in parameters developed for rock mass characterization. Three joint orientation parameters are compared in this article using a database containing geological and hydraulic information on scoured spillways. According to the detailed methodology, data is first classified according to rock quality using the GSI\u0000 chart\u0000 index. Then, for each GSI\u0000 chart\u0000 class, data is distributed according to the damage level, stream power and joint orientation parameter chosen. This study shows that no joint orientation parameter is currently able to accurately represent the effect of joint orientation on erosion of excellent- to poor-quality rock mass. Moreover, this study shows that the GSI\u0000 chart\u0000 index is not a rock quality index that completely evaluates rock erosion, since some relevant parameters for evaluating rock erodibility are not considered.\u0000","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49501490","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}
Recently, deep coal mining has posed a significant challenge due to the threat of water inrush from highly pressured aquifers in the floor strata. Water inrush in the floor strata are often associated with the structural characteristics of the underlying fault zones. The permeability of these fault zones is a critical factor in determining their potential as conduits for water flow. The variation in permeability is attributed to the varying cementation degree across different locations within the fault zones. Hence, this study is based on the key stratum theory and introduces the concept of a water-blocking key stratum within fault zones. This research focuses on the engineering context of the 16th coal seam above the lower coal seam in the 10603 working face of the Yangcun Coal Mine's tenth mining area. The study investigates the activation characteristics of the 10605F5 reverse fault zone, which cuts through the working face. Various methods, including test of simulation of similar materials and numerical simulations, are employed to analyze the hydraulic pressure distribution and the impact of mining activities on the water-blocking key stratum within the 10605F5 reverse fault zone. The research findings will provide valuable insights for preventing fault activation and water inrush.
{"title":"Water-blocking characteristics of fault zones with different structural combination of cementation degree","authors":"Yingzhou Chen, Shu-yun Zhu, Zhi-yong Yang","doi":"10.1144/qjegh2023-059","DOIUrl":"https://doi.org/10.1144/qjegh2023-059","url":null,"abstract":"Recently, deep coal mining has posed a significant challenge due to the threat of water inrush from highly pressured aquifers in the floor strata. Water inrush in the floor strata are often associated with the structural characteristics of the underlying fault zones. The permeability of these fault zones is a critical factor in determining their potential as conduits for water flow. The variation in permeability is attributed to the varying cementation degree across different locations within the fault zones. Hence, this study is based on the key stratum theory and introduces the concept of a water-blocking key stratum within fault zones. This research focuses on the engineering context of the 16th coal seam above the lower coal seam in the 10603 working face of the Yangcun Coal Mine's tenth mining area. The study investigates the activation characteristics of the 10605F5 reverse fault zone, which cuts through the working face. Various methods, including test of simulation of similar materials and numerical simulations, are employed to analyze the hydraulic pressure distribution and the impact of mining activities on the water-blocking key stratum within the 10605F5 reverse fault zone. The research findings will provide valuable insights for preventing fault activation and water inrush.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44562663","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 swelling of rock is a key issue in engineering. With large infrastructure construction trending toward complex geological conditions, an increasing number of projects could suffer from soft rock swelling. To solve this problem, an understanding of the damage evolution during the swelling process is essential. Argillaceous slate is a typical metamorphic rock and shows strong swelling characteristics in a water-rich environment due to its abundance of hydrophilic minerals. In this paper, argillaceous slate was selected as the research object. The damage evolution of argillaceous slate during swelling was explored via laboratory tests including swelling characteristic tests, soft rock needle penetration tests, and scanning electron microscope tests and damage theory. The research findings reveal that the slate swelling process in a water-rich environment could be divided into three stages. The swelling rate was relatively high in the early stage of the tests, slowed over time, and finally stabilized. However, the argillaceous slate strength decreased rapidly in the early stage, and the degradation rate was generally slow in the later stage. After water absorption, the clay mineral particles began to expand, and the microscopic structure of the argillaceous slate became complicated. The pore area increased, and the pore diameter decreased. A low degree of microscopic damage induced a high degree of macroscopic mechanical degradation. Additionally, the damage mechanism of argillaceous slate during swelling was discussed from micro- and macroscopic perspectives. A relationship between macroscopic mechanical degradation and microscopic damage to argillaceous slate was established, which can provide theoretical support for further research on soft rock swelling characteristics: The microscopic damage drove the macroscopic mechanical degradation.
{"title":"Swelling Damage Evolution of Argillaceous Slate in a Water-Rich Environment","authors":"Q. Zuo, Pan Li, Xinyi Li, Fubang Chen","doi":"10.1144/qjegh2022-128","DOIUrl":"https://doi.org/10.1144/qjegh2022-128","url":null,"abstract":"The swelling of rock is a key issue in engineering. With large infrastructure construction trending toward complex geological conditions, an increasing number of projects could suffer from soft rock swelling. To solve this problem, an understanding of the damage evolution during the swelling process is essential. Argillaceous slate is a typical metamorphic rock and shows strong swelling characteristics in a water-rich environment due to its abundance of hydrophilic minerals. In this paper, argillaceous slate was selected as the research object. The damage evolution of argillaceous slate during swelling was explored via laboratory tests including swelling characteristic tests, soft rock needle penetration tests, and scanning electron microscope tests and damage theory. The research findings reveal that the slate swelling process in a water-rich environment could be divided into three stages. The swelling rate was relatively high in the early stage of the tests, slowed over time, and finally stabilized. However, the argillaceous slate strength decreased rapidly in the early stage, and the degradation rate was generally slow in the later stage. After water absorption, the clay mineral particles began to expand, and the microscopic structure of the argillaceous slate became complicated. The pore area increased, and the pore diameter decreased. A low degree of microscopic damage induced a high degree of macroscopic mechanical degradation. Additionally, the damage mechanism of argillaceous slate during swelling was discussed from micro- and macroscopic perspectives. A relationship between macroscopic mechanical degradation and microscopic damage to argillaceous slate was established, which can provide theoretical support for further research on soft rock swelling characteristics: The microscopic damage drove the macroscopic mechanical degradation.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44698467","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 study is focused on the assessment of the stability of the lower part of the right slope of the Danube River. The research area is situated in the town of Tutrakan, Northeastern Bulgaria. The present study investigates the likelihood of activating landslide processes due to construction works on the water supply and sewerage network of the town, as well as the influence of the natural geological and hydrogeological settings of the region. The research area is part of the Danubian Plain. The groundwater level lies between 7 and 26 m below the surface, in the sandy sediments and limestones of the Pliocene that form the semi-confined to unconfined aquifer. They are mainly formed by infiltration of precipitation through the loess layer. The groundwater discharge is carried out naturally and technogenically towards the Danube, through a herringbone system of drains built in the toe of the landslide cirques. The assessment of the slope stability was made for the different hypotheses – natural (momentous – including the existing buildings), constructional (including excavations), primary and specific (including seismic forces) combination of stresses. The different geodynamic models, taking into account the influence of groundwater, the influence of different destabilizing factors and seismic impact, show that the slope, as well as the studied sections of it – the landslide cirques, are in a stabilized state, with safety coefficients (Fs > 1). According to the mechanism of deformation, the landslides are classified as a translational slide, and deep seated according to the depth of the slip zone. They are contemporary and currently active. The study confirms the hypothesis of the origin of the landslide masses in the area, formed as a mixture of loess material and Pliocene clays. The groundwater level is directly related to the current state of the landslide slope stability.
{"title":"Influence of geological and hydrogeological settings in assessing the stability of a landslide slope in the Tutrakan area, Northeastern Bulgaria","authors":"Lyubomir Angelov, Tanya Vasileva","doi":"10.52321/igh.37.1.47","DOIUrl":"https://doi.org/10.52321/igh.37.1.47","url":null,"abstract":"The study is focused on the assessment of the stability of the lower part of the right slope of the Danube River. The research area is situated in the town of Tutrakan, Northeastern Bulgaria. The present study investigates the likelihood of activating landslide processes due to construction works on the water supply and sewerage network of the town, as well as the influence of the natural geological and hydrogeological settings of the region. The research area is part of the Danubian Plain. The groundwater level lies between 7 and 26 m below the surface, in the sandy sediments and limestones of the Pliocene that form the semi-confined to unconfined aquifer. They are mainly formed by infiltration of precipitation through the loess layer. The groundwater discharge is carried out naturally and technogenically towards the Danube, through a herringbone system of drains built in the toe of the landslide cirques. The assessment of the slope stability was made for the different hypotheses – natural (momentous – including the existing buildings), constructional (including excavations), primary and specific (including seismic forces) combination of stresses. The different geodynamic models, taking into account the influence of groundwater, the influence of different destabilizing factors and seismic impact, show that the slope, as well as the studied sections of it – the landslide cirques, are in a stabilized state, with safety coefficients (Fs > 1). According to the mechanism of deformation, the landslides are classified as a translational slide, and deep seated according to the depth of the slip zone. They are contemporary and currently active. The study confirms the hypothesis of the origin of the landslide masses in the area, formed as a mixture of loess material and Pliocene clays. The groundwater level is directly related to the current state of the landslide slope stability.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91214787","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 main purpose of the study is to develop models for the strength reliability of closed spillways at earth-fill dams. The object of the research is closed mine-type spillway structures. The strength reliability model of a closed spillway structure includes a material model, a shape model, a model of actual load, and a fracture model. The material model in most cases is reinforced concrete. The shape model is very important, especially for precast culverts of glory hole spillways, because giving it a certain shape can significantly reduce the value of stresses acting in weak sections. As a result of the stress reduction, there is a decrease in material requirements, primarily for metals, leading to reduced energy and economic costs. This also makes it possible to increase the reliability and durability of such structures, increase their operational safety, and adapt them to various operating conditions. The shape model for the culvert is justified. The load model determines the behavior of the structure during construction and operation. This article suggests a justification for the methodology for calculating the strength of a precast culvert of segment blocks. The methodology allows to perform strength analysis of culverts of closed spillways with a cross-section outline similar to a membrane. The state of reinforced concrete load-carrying units under various combinations of loads has been studied. The limits of stresses and displacements, the excess of which can lead to destruction in the load-carrying units, are determined.
{"title":"Justification of cross direction profile of pipe-culvert of closed mine-type spillway","authors":"T. Lyapota","doi":"10.52321/igh.37.1.35","DOIUrl":"https://doi.org/10.52321/igh.37.1.35","url":null,"abstract":"The main purpose of the study is to develop models for the strength reliability of closed spillways at earth-fill dams. The object of the research is closed mine-type spillway structures. The strength reliability model of a closed spillway structure includes a material model, a shape model, a model of actual load, and a fracture model. The material model in most cases is reinforced concrete. The shape model is very important, especially for precast culverts of glory hole spillways, because giving it a certain shape can significantly reduce the value of stresses acting in weak sections. As a result of the stress reduction, there is a decrease in material requirements, primarily for metals, leading to reduced energy and economic costs. This also makes it possible to increase the reliability and durability of such structures, increase their operational safety, and adapt them to various operating conditions. The shape model for the culvert is justified. The load model determines the behavior of the structure during construction and operation. This article suggests a justification for the methodology for calculating the strength of a precast culvert of segment blocks. The methodology allows to perform strength analysis of culverts of closed spillways with a cross-section outline similar to a membrane. The state of reinforced concrete load-carrying units under various combinations of loads has been studied. The limits of stresses and displacements, the excess of which can lead to destruction in the load-carrying units, are determined.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88020800","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}
A database containing ca 27000 records of Quaternary lithostratigraphy extracted from ca 5800 individual boreholes drilled to a variety of depths, has been compiled from information contained in logs recorded and held by British Geological Survey (BGS) and from the Crossrail (CR) project. After ‘cleaning’ and quality assessment the raw borehole log data have been investigated for patterns in distribution, and variations in the Quaternary facies across Greater London. In particular, the analysis of Quaternary River Terrace Deposits has been focused on here and a summary of relevant published terminology and nomenclature is also included in this report, as an aid to understanding. The spatial distributions of each major Quaternary lithostratigraphic interval, as identified in the log descriptions, are also presented as point locations in map form, and in comparison with the corresponding BGS mapped outcrop patterns of the respective lithostratigraphic units. The presence of various specific clasts in the log descriptions, e.g. cobbles and chalk clasts, is also presented at stratigraphic member levels against their apparent source outcrops. For instance, cobbles recorded from the Boyne Hill Terrace intervals are concentrated in the eastern outcrops and reflect the Wealden source and former river system of the Darrent – Wid towards the Essex coast at Maldon. Similarly, the presence and distribution of shell and chalk clasts within river terrace sands and gravels reflect the geology of the underlying subcropping strata of Lower Shelly Clay and Chalk respectively. The Crossrail data also include some grain size information from sieve analysis and some engineering in situ test values, which require careful analysis beyond the scope of this work but are potentially useful. The grain size distributions for some of the samples from the river terrace sands and gravels show fining up and coarsening up sequences, and geographical grain size trends in various stratigraphic intervals. The recorded presence of faults, fractures and fissures, as identified by the drilling contractors or logging geologists, are also extracted and mapped. Supplementary evidence, from repeated stratigraphy or improbable spatial proximity changes in subcrop depths, suggest a cause other than deposition for such changes and on the presumption that their cause is natural, are interpreted as likely to be representative of faulting of some kind, including low angle thrust faults. Faulting is also considered to have controlled the distribution of several interglacial silt members and is the subject of considerable research in the deeper intervals of London stratigraphy, so is only briefly dealt with here. To define the period over which tectonic structures, now known to exist within the strata of the London Basin, were active requires an analysis of Quaternary deposits that overlie them. This Technical Note provides an initial review of the data available from boreholes for su
从英国地质调查局(BGS)和横贯铁路(CR)项目记录和保存的日志信息中收集了大约27000条第四纪岩石地层学记录，这些记录是从5800个不同深度的钻孔中提取的。经过“清洗”和质量评估，原始钻孔测井数据的分布模式和第四纪相在大伦敦地区的变化进行了研究。本报告特别着重分析了第四纪河流阶地沉积，并对已发表的相关术语和命名法进行了总结，以帮助理解。测井描述中确定的各主要第四纪岩石地层段的空间分布也以图的形式表示为点位，并与相应的BGS绘制的各岩石地层单元的露头格局进行比较。测井描述中各种特殊碎屑的存在，如鹅卵石和白垩碎屑，也在地层成员水平上与其明显的来源露头相比较。例如，从Boyne Hill Terrace区间记录下来的鹅卵石集中在东部露头，反映了威尔登的源头和达伦特-维德河在马尔登流向埃塞克斯海岸的前河流系统。同样，河阶地砂和砾石中贝壳碎屑和白垩碎屑的存在和分布，分别反映了下雪利粘土和白垩下垫地层的地质情况。Crossrail数据还包括筛分分析的一些粒度信息和一些工程现场测试值，这些数据需要仔细分析，超出了本工作的范围，但可能有用。部分阶地砂和砾石样品的粒度分布呈现出细化和粗化的序列，以及不同层段的地理粒度趋势。由钻井承包商或测井地质学家识别的断层、裂缝和裂缝的记录也被提取并绘制成地图。从重复的地层学或不可能的次层深度空间接近变化中获得的补充证据表明，这种变化是由沉积以外的原因造成的，并且假设它们的原因是自然的，这些证据被解释为可能是某种断裂的代表，包括低角度逆冲断层。断裂作用也被认为控制了几个间冰期粉砂体的分布，是伦敦地层学中较深层段大量研究的主题，因此这里只作简要讨论。要确定伦敦盆地地层中存在的构造构造的活动时期，需要对其上的第四纪沉积物进行分析。本技术说明对此类工作和任何其他需要了解这些矿床的研究所获得的钻孔数据进行了初步审查。专题合集:本文是伦敦地质及其对地面工程的影响合集的一部分，可在:https://www.lyellcollection.org/topic/collections/geology-of-london-and-its-implications-for-ground-engineering补充材料:https://doi.org/10.6084/m9.figshare.c.6700313
{"title":"The distributions and variations of Quaternary Thames River Terrace deposits of Greater London","authors":"Elizabeth Aston, P. Mason","doi":"10.1144/qjegh2023-016","DOIUrl":"https://doi.org/10.1144/qjegh2023-016","url":null,"abstract":"\u0000 A database containing\u0000 ca\u0000 27000 records of Quaternary lithostratigraphy extracted from\u0000 ca\u0000 5800 individual boreholes drilled to a variety of depths, has been compiled from information contained in logs recorded and held by British Geological Survey (BGS) and from the Crossrail (CR) project. After ‘cleaning’ and quality assessment the raw borehole log data have been investigated for patterns in distribution, and variations in the Quaternary facies across Greater London.\u0000 \u0000 In particular, the analysis of Quaternary River Terrace Deposits has been focused on here and a summary of relevant published terminology and nomenclature is also included in this report, as an aid to understanding. The spatial distributions of each major Quaternary lithostratigraphic interval, as identified in the log descriptions, are also presented as point locations in map form, and in comparison with the corresponding BGS mapped outcrop patterns of the respective lithostratigraphic units.\u0000 The presence of various specific clasts in the log descriptions, e.g. cobbles and chalk clasts, is also presented at stratigraphic member levels against their apparent source outcrops. For instance, cobbles recorded from the Boyne Hill Terrace intervals are concentrated in the eastern outcrops and reflect the Wealden source and former river system of the Darrent – Wid towards the Essex coast at Maldon. Similarly, the presence and distribution of shell and chalk clasts within river terrace sands and gravels reflect the geology of the underlying subcropping strata of Lower Shelly Clay and Chalk respectively.\u0000 The Crossrail data also include some grain size information from sieve analysis and some engineering in situ test values, which require careful analysis beyond the scope of this work but are potentially useful. The grain size distributions for some of the samples from the river terrace sands and gravels show fining up and coarsening up sequences, and geographical grain size trends in various stratigraphic intervals.\u0000 The recorded presence of faults, fractures and fissures, as identified by the drilling contractors or logging geologists, are also extracted and mapped. Supplementary evidence, from repeated stratigraphy or improbable spatial proximity changes in subcrop depths, suggest a cause other than deposition for such changes and on the presumption that their cause is natural, are interpreted as likely to be representative of faulting of some kind, including low angle thrust faults. Faulting is also considered to have controlled the distribution of several interglacial silt members and is the subject of considerable research in the deeper intervals of London stratigraphy, so is only briefly dealt with here. To define the period over which tectonic structures, now known to exist within the strata of the London Basin, were active requires an analysis of Quaternary deposits that overlie them. This Technical Note provides an initial review of the data available from boreholes for su","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44681561","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}
Sourour Elgattoussi, F. Melki, H. Gabtni, G. B. Rea
We present the characterization of a poorly studied karstic aquifer, documenting the geometry, resistivity properties and the control of structural discontinuities affecting the outcropping Ypresian limestone in the Mateur imbricated thrust zone in Northern Tunisia. The karst system was produced by meteoric diagenesis. Geophysical methods and field investigations were useful in extracting geologic features. First, our findings suggest that the N110 to N140 directions are the preferred dissolution paths oriented parallel to strike-slip and extensional faults. Second, the gravity data analysis (regional-residual separation, horizontal gravity gradient, and Euler deconvolution) show a particular tectonic node as a junction of NE-SW and NW-SE directions. Third, the 2D electrical resistivity models exhibit the various karstification typologies with high (more than 1000 Ω m), medium (between 200 and 1000 Ω m) to low (less than 100) electrical resistivity zones. These electrical resistivity models contributed to the establishment of the conceptual structural model of the global karst features. Finally, 2D ERT and 1D time domain electromagnetic analysis highlighted the presence of potential water zones integrated into the aquifer. Thematic collection: This article is part of the Karst: Characterization, Hazards & Hydrogeology collection available at: https://www.lyellcollection.org/topic/collections/karst
{"title":"Structural control on Ypresian karstic aquifer revealed by an integrated geophysical and geological approach: the Mateur imbricated thrust zone (Northern Tunisia)","authors":"Sourour Elgattoussi, F. Melki, H. Gabtni, G. B. Rea","doi":"10.1144/qjegh2023-049","DOIUrl":"https://doi.org/10.1144/qjegh2023-049","url":null,"abstract":"\u0000 We present the characterization of a poorly studied karstic aquifer, documenting the geometry, resistivity properties and the control of structural discontinuities affecting the outcropping Ypresian limestone in the Mateur imbricated thrust zone in Northern Tunisia. The karst system was produced by meteoric diagenesis. Geophysical methods and field investigations were useful in extracting geologic features. First, our findings suggest that the N110 to N140 directions are the preferred dissolution paths oriented parallel to strike-slip and extensional faults. Second, the gravity data analysis (regional-residual separation, horizontal gravity gradient, and Euler deconvolution) show a particular tectonic node as a junction of NE-SW and NW-SE directions. Third, the 2D electrical resistivity models exhibit the various karstification typologies with high (more than 1000\u0000 \u0000 \u0000 Ω\u0000 \u0000 \u0000 m), medium (between 200 and 1000\u0000 \u0000 \u0000 Ω\u0000 \u0000 \u0000 m) to low (less than 100) electrical resistivity zones. These electrical resistivity models contributed to the establishment of the conceptual structural model of the global karst features. Finally, 2D ERT and 1D time domain electromagnetic analysis highlighted the presence of potential water zones integrated into the aquifer.\u0000 \u0000 \u0000 Thematic collection:\u0000 This article is part of the Karst: Characterization, Hazards & Hydrogeology collection available at:\u0000 https://www.lyellcollection.org/topic/collections/karst\u0000","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44241031","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}
K. Zhao, Wenqiang Ao, Yajing Yan, Yichen Shi, Jun Wu, Lijie Guo, Lang Liu
During the construction of underground projects, different types of rock are often in a cyclic state of loading and unloading. Therefore, cyclic fracturing experiments on metamorphic sandstone, slate and granite from one mine site. Based on the basic parameters of acoustic emission(AE), the damage processes and damage precursor patterns of different types of rock samples are analysed. The results of the study show that there is basically no AE signal generated during the unloading phase of the first two cycles of loading, and less acoustic emission signal is generated in the loading stage; In the experimental process of different types of rock samples, when the value of CV( r ) is larger, it can be considered as large scale crack dominance; small scale crack dominance when the value of CV( r ) is small, and CV( r ) values are more accurate than AE b-values in determining the pattern of cracking within a rock sample. With different internal crack development during cyclic splitting, can focus on the changes in the AE loading energy ratio and CV( r ) values before damage destabilization occurs. The Felicity ratio, CV( r ) value and loading energy ratio can be used in combination in practical engineering to improve the accuracy of determining rock stability.
{"title":"Damage evolution process and damage precursor law under cyclic splitting action of different types of rocks","authors":"K. Zhao, Wenqiang Ao, Yajing Yan, Yichen Shi, Jun Wu, Lijie Guo, Lang Liu","doi":"10.1144/qjegh2022-067","DOIUrl":"https://doi.org/10.1144/qjegh2022-067","url":null,"abstract":"\u0000 During the construction of underground projects, different types of rock are often in a cyclic state of loading and unloading. Therefore, cyclic fracturing experiments on metamorphic sandstone, slate and granite from one mine site. Based on the basic parameters of acoustic emission(AE), the damage processes and damage precursor patterns of different types of rock samples are analysed. The results of the study show that there is basically no AE signal generated during the unloading phase of the first two cycles of loading, and less acoustic emission signal is generated in the loading stage; In the experimental process of different types of rock samples, when the value of CV(\u0000 r\u0000 ) is larger, it can be considered as large scale crack dominance; small scale crack dominance when the value of CV(\u0000 r\u0000 ) is small, and CV(\u0000 r\u0000 ) values are more accurate than AE b-values in determining the pattern of cracking within a rock sample. With different internal crack development during cyclic splitting, can focus on the changes in the AE loading energy ratio and CV(\u0000 r\u0000 ) values before damage destabilization occurs. The Felicity ratio, CV(\u0000 r\u0000 ) value and loading energy ratio can be used in combination in practical engineering to improve the accuracy of determining rock stability.\u0000","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48596473","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}
Hong-yuan Fu, Xiao Yu, Jie Liu, Ling Zeng, Xiao-wei Chen
This study aims to improve the mechanical properties of predisintegrated carbonaceous mudstone (PCM) used as an embankment fill. The four factors used in the orthogonal design test are nano-Al 2 O 3 content, cement content, water content and compaction. Afterward, the strength characteristics and micromechanisms of PCM modified by nano-Al 2 O 3 and cement are studied through triaxial compression tests, X-ray diffraction analysis and SEM observations. The results show that the failure mode of PCM changes from bulging failure to shear failure when the nano-Al 2 O 3 and cement contents are increased. The order in which the factors affected the cohesion of PCM is cement content, nano-Al 2 O 3 content, water content and compaction. At a given cement content, the cohesion of PCM with an optimal compaction of 96% and a water content of 8% increases and then decreases with increasing nano-Al 2 O 3 content. The increase in the internal friction angle is proportional to the nano-Al 2 O 3 content when the cement content is between 0 and 4%. Controlling the contents of nano-Al 2 O 3 and cement to 0.3% and 8% results in a synergistic effect of both materials on shear strength. Nano-Al 2 O 3 improves the cohesion and friction strength of PCM through accelerating the hydration of cement and optimizing the structure of hydration products.
{"title":"Study on the Strength Properties and Micromechanisms of Nano-Al\u0000 2\u0000 O\u0000 3\u0000 -Modified Predisintegrated Carbonaceous Mudstone Based on Orthogonal Design","authors":"Hong-yuan Fu, Xiao Yu, Jie Liu, Ling Zeng, Xiao-wei Chen","doi":"10.1144/qjegh2023-018","DOIUrl":"https://doi.org/10.1144/qjegh2023-018","url":null,"abstract":"\u0000 This study aims to improve the mechanical properties of predisintegrated carbonaceous mudstone (PCM) used as an embankment fill. The four factors used in the orthogonal design test are nano-Al\u0000 2\u0000 O\u0000 3\u0000 content, cement content, water content and compaction. Afterward, the strength characteristics and micromechanisms of PCM modified by nano-Al\u0000 2\u0000 O\u0000 3\u0000 and cement are studied through triaxial compression tests, X-ray diffraction analysis and SEM observations. The results show that the failure mode of PCM changes from bulging failure to shear failure when the nano-Al\u0000 2\u0000 O\u0000 3\u0000 and cement contents are increased. The order in which the factors affected the cohesion of PCM is cement content, nano-Al\u0000 2\u0000 O\u0000 3\u0000 content, water content and compaction. At a given cement content, the cohesion of PCM with an optimal compaction of 96% and a water content of 8% increases and then decreases with increasing nano-Al\u0000 2\u0000 O\u0000 3\u0000 content. The increase in the internal friction angle is proportional to the nano-Al\u0000 2\u0000 O\u0000 3\u0000 content when the cement content is between 0 and 4%. Controlling the contents of nano-Al\u0000 2\u0000 O\u0000 3\u0000 and cement to 0.3% and 8% results in a synergistic effect of both materials on shear strength. Nano-Al\u0000 2\u0000 O\u0000 3\u0000 improves the cohesion and friction strength of PCM through accelerating the hydration of cement and optimizing the structure of hydration products.\u0000","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46399496","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}
To facilitate the automation accuracy of rock joint mapping, a new method based on color space was proposed for the semi-automatic identification and orientation calculation of rock joints. The developed method in this study comprises four-step: (1) the point color space and point curvature were calculated based on the point normal and xyz-coordinates respectively; (2) the rock joint sets were identified from point clouds based on the difference in point color space and point curvature; (3) each single rock joint was extracted from the aforementioned joint sets using a density-based spatial clustering of applications with noise (DBSCAN); and (4) the orientation was determined according to the point normals of the fitting planes of the points on each detected rock joint. A dodecahedron was used to demonstrate the procedures of rock joint detection and orientation calculation, and two outcrop cases were selected to further verify the effectiveness of the proposed method. The results of all cases indicate that the orientation difference between manual measurement and the proposed method was less than 2°. The codes that support the findings of this study are publicly shared on GitHub ( https://github.com/DisDet/DisDetCIELAB ).
{"title":"Rock Joints Detection from 3D Point Clouds Based on Color Space","authors":"Yunfeng Ge, Bei Cao, Qianwang Chen, Yu Wang","doi":"10.1144/qjegh2023-012","DOIUrl":"https://doi.org/10.1144/qjegh2023-012","url":null,"abstract":"\u0000 To facilitate the automation accuracy of rock joint mapping, a new method based on color space was proposed for the semi-automatic identification and orientation calculation of rock joints. The developed method in this study comprises four-step: (1) the point color space and point curvature were calculated based on the point normal and xyz-coordinates respectively; (2) the rock joint sets were identified from point clouds based on the difference in point color space and point curvature; (3) each single rock joint was extracted from the aforementioned joint sets using a density-based spatial clustering of applications with noise (DBSCAN); and (4) the orientation was determined according to the point normals of the fitting planes of the points on each detected rock joint. A dodecahedron was used to demonstrate the procedures of rock joint detection and orientation calculation, and two outcrop cases were selected to further verify the effectiveness of the proposed method. The results of all cases indicate that the orientation difference between manual measurement and the proposed method was less than 2°. The codes that support the findings of this study are publicly shared on GitHub (\u0000 https://github.com/DisDet/DisDetCIELAB\u0000 ).\u0000","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44436074","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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