In alignment with the Cornwall & Isles of Scilly Shoreline Management Plan (SMP2), adopted by Cornwall Council, the Coverack North Coast Protection Scheme comprised the construction of a circa 125m long rock armour revetment, and 55m long retaining wall, at Coverack Cove on the Lizard peninsula in Cornwall, UK. This was to prevent sea erosion impacting vehicle access via the B3294, the main public highway into Coverack. The site of the proposed works on Coverack Beach is part of a Natural England designated Site of Special Scientific Interest (SSSI) for its geology, specifically the exposure on the foreshore of an almost continuous cross section of a palaeo-Moho, the former boundary between the earth's crust and underlying mantle. Following a period of consultation, a set of management proposals and mitigation measures were agreed with Natural England and Cornwall Council to protect and offset the impact of the proposed works on the SSSI asset. It is sometimes difficult to reconcile the issue of protecting communities from coastal erosion and ensuring the protection of geological assets. This can be mitigated if a balanced approach is adopted, and the work is sensitively managed to offset the impact of coastal protection schemes such of this.
{"title":"Managing a potential conflict between the protection of geological sites and the need to safeguard essential road infrastructure: the Coverack North Coast Protection Scheme and palaeo-Moho in Cornwall, UK","authors":"Holme Andrew","doi":"10.1144/qjegh2024-040","DOIUrl":"https://doi.org/10.1144/qjegh2024-040","url":null,"abstract":"In alignment with the Cornwall & Isles of Scilly Shoreline Management Plan (SMP2), adopted by Cornwall Council, the Coverack North Coast Protection Scheme comprised the construction of a circa 125m long rock armour revetment, and 55m long retaining wall, at Coverack Cove on the Lizard peninsula in Cornwall, UK. This was to prevent sea erosion impacting vehicle access via the B3294, the main public highway into Coverack.\u0000 The site of the proposed works on Coverack Beach is part of a Natural England designated Site of Special Scientific Interest (SSSI) for its geology, specifically the exposure on the foreshore of an almost continuous cross section of a palaeo-Moho, the former boundary between the earth's crust and underlying mantle.\u0000 Following a period of consultation, a set of management proposals and mitigation measures were agreed with Natural England and Cornwall Council to protect and offset the impact of the proposed works on the SSSI asset.\u0000 It is sometimes difficult to reconcile the issue of protecting communities from coastal erosion and ensuring the protection of geological assets. This can be mitigated if a balanced approach is adopted, and the work is sensitively managed to offset the impact of coastal protection schemes such of this.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141812402","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}
Kevin M. Briggs, Yuderka Trinidad González, G. J. Meijer, Andrew Ridley, W. Powrie, Simon Butler, N. Sartain
Monitoring the changes in pore water pressure associated with the construction of earthworks can yield information on the stiffness and permeability of the ground, as well as how the natural groundwater regime might be impacted. This paper presents three years of pore water pressure measurements in weathered Lias Group mudstone, obtained from a trial cutting and a trial embankment constructed for the UK's High Speed Two (HS2) railway. The immediate changes in pore water pressure were small in relation to the changes in total stress imposed. This can be explained by the consolidation or swelling during the period of construction, combined with the sensitivity of very stiff clays and mudstones to a very small (0.5%) reduction in the degree of saturation. In the longer-term, pore water pressures reduced across the site owing to the reduction in ground level at the trial cutting. Rates of pore water pressure change were accelerated by more permeable limestone within the ground profile reducing drainage path lengths. It is concluded that construction-induced pore water pressure changes may be smaller, and their rate of dissipation more rapid, in weathered clays and mudstones such as those of the Lias Group than in younger, more compressible clay deposits.
{"title":"The influence of earthworks construction on pore water pressures in clays and mudstones of the Lias Group","authors":"Kevin M. Briggs, Yuderka Trinidad González, G. J. Meijer, Andrew Ridley, W. Powrie, Simon Butler, N. Sartain","doi":"10.1144/qjegh2024-036","DOIUrl":"https://doi.org/10.1144/qjegh2024-036","url":null,"abstract":"Monitoring the changes in pore water pressure associated with the construction of earthworks can yield information on the stiffness and permeability of the ground, as well as how the natural groundwater regime might be impacted. This paper presents three years of pore water pressure measurements in weathered Lias Group mudstone, obtained from a trial cutting and a trial embankment constructed for the UK's High Speed Two (HS2) railway. The immediate changes in pore water pressure were small in relation to the changes in total stress imposed. This can be explained by the consolidation or swelling during the period of construction, combined with the sensitivity of very stiff clays and mudstones to a very small (0.5%) reduction in the degree of saturation. In the longer-term, pore water pressures reduced across the site owing to the reduction in ground level at the trial cutting. Rates of pore water pressure change were accelerated by more permeable limestone within the ground profile reducing drainage path lengths. It is concluded that construction-induced pore water pressure changes may be smaller, and their rate of dissipation more rapid, in weathered clays and mudstones such as those of the Lias Group than in younger, more compressible clay deposits.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141822825","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}
‘Geohazard’ has become one of the classic terms of engineering geology, a contraction of the term geologic hazard. It seems that everyone knows what a geohazard is, but then seem to offer examples that betray significant differences of opinion. In this paper, we examine how the almost parallel emergence of the term through different disciplines, geography (disaster management), geology (environmental and urban geology) and geotechnical engineering, has led to a wide diversity of perspectives. We describe the diversity of geohazard classification and discuss how geohazards should be best viewed in the context of risk (the potential for undesirable consequences). Attention is drawn to the way in which geohazards are addressed in current guidance, notably IAEG C25 and Eurocode 7. In conclusion, we present the key points underpinning the concept of a geohazard.
{"title":"What is a Geohazard?","authors":"E. M. Lee, J. S. Griffiths","doi":"10.1144/qjegh2024-034","DOIUrl":"https://doi.org/10.1144/qjegh2024-034","url":null,"abstract":"‘Geohazard’ has become one of the classic terms of engineering geology, a contraction of the term geologic hazard. It seems that everyone knows what a geohazard is, but then seem to offer examples that betray significant differences of opinion. In this paper, we examine how the almost parallel emergence of the term through different disciplines, geography (disaster management), geology (environmental and urban geology) and geotechnical engineering, has led to a wide diversity of perspectives. We describe the diversity of geohazard classification and discuss how geohazards should be best viewed in the context of risk (the potential for undesirable consequences). Attention is drawn to the way in which geohazards are addressed in current guidance, notably IAEG C25 and Eurocode 7. In conclusion, we present the key points underpinning the concept of a geohazard.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141822322","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}
Yunchen Deng, Yi Luo, D. Qu, Xuan Zhang, Xin Liu, Han Luo, Xinping Li
A stress-seepage-damage coupling model considering the long-term creep of deep rock mass was established to study the mechanism of evolution of stability of the surrounding rock during reconstruction and excavation of abandoned deep water-rich roadways in the mine. The research shows that the maximum compressive stress in the circular cavern is significantly lower than that in the horseshoe-shaped cavern. Stress is distributed more uniformly in the circular cavern, and appropriately enlarging the size of the reconstructed excavation site can improve the stability of the surrounding rock. As the creep duration for abandoned roadways increases from one to nine years, the growth rates for vault settlement and horizontal clearance convergence remain constant and the roadway undergoes steady-state creep. With the increasing burial depth of the abandoned roadway (200 ∼ 400 m), a pressure arch is gradually formed in the roadway roof in the reconstruction and mining process. The surrounding rock forms a 'self-bearing structure' with arch mechanical characteristics and load transfer mechanism to maintain its own stability, and the overall bearing capacity of the surrounding rock is greatly improved. However, once the burial depth exceeds 400 m, the effect of the pressure arch begins to diminish with further increases in burial depth. Furthermore, pore water pressure significantly weakens the surrounding rocks.
{"title":"Coupling effects of stress, seepage and damage during reconstruction and excavation of abandoned deep water-rich roadways","authors":"Yunchen Deng, Yi Luo, D. Qu, Xuan Zhang, Xin Liu, Han Luo, Xinping Li","doi":"10.1144/qjegh2024-014","DOIUrl":"https://doi.org/10.1144/qjegh2024-014","url":null,"abstract":"A stress-seepage-damage coupling model considering the long-term creep of deep rock mass was established to study the mechanism of evolution of stability of the surrounding rock during reconstruction and excavation of abandoned deep water-rich roadways in the mine. The research shows that the maximum compressive stress in the circular cavern is significantly lower than that in the horseshoe-shaped cavern. Stress is distributed more uniformly in the circular cavern, and appropriately enlarging the size of the reconstructed excavation site can improve the stability of the surrounding rock. As the creep duration for abandoned roadways increases from one to nine years, the growth rates for vault settlement and horizontal clearance convergence remain constant and the roadway undergoes steady-state creep. With the increasing burial depth of the abandoned roadway (200 ∼ 400 m), a pressure arch is gradually formed in the roadway roof in the reconstruction and mining process. The surrounding rock forms a 'self-bearing structure' with arch mechanical characteristics and load transfer mechanism to maintain its own stability, and the overall bearing capacity of the surrounding rock is greatly improved. However, once the burial depth exceeds 400 m, the effect of the pressure arch begins to diminish with further increases in burial depth. Furthermore, pore water pressure significantly weakens the surrounding rocks.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141346504","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}
It is planned to reopen Midsomer Norton Railway Station, which is a station on the Somerset & Dorset Heritage Railway Line, to traffic. As a first step, Midsomer Norton will be a terminus and it is proposed to build a siding and a depot for the terminating trains. However, a ground investigation is essential before commencing construction of the siding and the depot, as it is a vital part of any civil engineering process. The ground's behaviour must be known in order for a structure to be supported by it, therefore data from the ground investigation is a reference for any kind of structures development. This study covers a site investigation including a desk study, walkover survey, sampling and laboratory testing for the feasibility of a suitable design. Moisture content testing, liquid limit and plastic limit tests, standard compaction testing, shear vane tests and triaxial compression tests were carried out to determine the soil characteristics and to analyse the soil behaviour. A strong recommendation was made to follow systems engineering approach in the construction phase, as well as the design stage. Dependability of the system is ensured by the good use of V – process of systems engineering.
计划重新开放位于萨默塞特和多塞特传统铁路线上的米德尔诺顿火车站。作为第一步，米德尔诺顿将成为一个终点站，建议为终点站的列车建造一个侧线和一个车库。然而，在开始修建侧线和车库之前，必须进行地层勘测，因为这是任何土木工程过程中的一个重要部分。必须了解地层的特性，才能为结构提供支撑，因此地层勘察的数据对任何结构的开发都具有参考价值。本研究涵盖现场勘察，包括案头研究、步行勘察、取样和实验室测试，以确定合适设计的可行性。为确定土壤特性和分析土壤行为，进行了含水量测试、液限和塑限测试、标准压实测试、剪切叶片测试和三轴压缩测试。强烈建议在施工阶段和设计阶段都采用系统工程方法。系统工程的 V 过程的良好使用可确保系统的可靠性。
{"title":"Adopting Systems Engineering Approach to a Feasibility Study of Siding Development at Midsomer Norton Station","authors":"Üsame Ekici","doi":"10.1144/qjegh2023-089","DOIUrl":"https://doi.org/10.1144/qjegh2023-089","url":null,"abstract":"It is planned to reopen Midsomer Norton Railway Station, which is a station on the Somerset & Dorset Heritage Railway Line, to traffic. As a first step, Midsomer Norton will be a terminus and it is proposed to build a siding and a depot for the terminating trains. However, a ground investigation is essential before commencing construction of the siding and the depot, as it is a vital part of any civil engineering process. The ground's behaviour must be known in order for a structure to be supported by it, therefore data from the ground investigation is a reference for any kind of structures development. This study covers a site investigation including a desk study, walkover survey, sampling and laboratory testing for the feasibility of a suitable design. Moisture content testing, liquid limit and plastic limit tests, standard compaction testing, shear vane tests and triaxial compression tests were carried out to determine the soil characteristics and to analyse the soil behaviour. A strong recommendation was made to follow systems engineering approach in the construction phase, as well as the design stage. Dependability of the system is ensured by the good use of V – process of systems engineering.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141364555","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}
Yu-long Cui, Chen Chen, Lulu Zhu, Chong Xu, Ming Xu, Jun Zheng
The eastern Himalayan syntaxis region is located on the eastern edge of the Qinghai-Tibet Plateau, and it's one of the regions with the most intense geological tectonic activity in the world. There have been many large-scale landslides in the eastern Himalayan syntaxis region and the distribution of these landslides is of great significance for the inversion of regional tectonic activity strength, major engineering construction, and urban-rural planning. However, no researchers have systematically studied all these landslides of this area. First, based on Google Earth satellite imagery, landslides were identified using artificial visual interpretation. Second, 11 landslide-influencing factors were selected, comprising topographic factors (elevation, slope, aspect, curvature), geological environmental factors (strata, distance to faults, distance to waters, distance to roads, normalized difference vegetation index), inducing factors (peak ground acceleration, rainfall), the relationships between the distribution law of landslides and influencing factors were analyzed. Finally, the logistic regression model (LR), the weight of evidence model (WoE), and the weight of evidence- logistic regression (WoE–LR) coupled model were used to evaluate the landslide susceptibility.
{"title":"Spatial distribution law of landslides and landslide susceptibility assessment in the Eastern Himalayan Syntaxis Region","authors":"Yu-long Cui, Chen Chen, Lulu Zhu, Chong Xu, Ming Xu, Jun Zheng","doi":"10.1144/qjegh2023-144","DOIUrl":"https://doi.org/10.1144/qjegh2023-144","url":null,"abstract":"The eastern Himalayan syntaxis region is located on the eastern edge of the Qinghai-Tibet Plateau, and it's one of the regions with the most intense geological tectonic activity in the world. There have been many large-scale landslides in the eastern Himalayan syntaxis region and the distribution of these landslides is of great significance for the inversion of regional tectonic activity strength, major engineering construction, and urban-rural planning. However, no researchers have systematically studied all these landslides of this area. First, based on Google Earth satellite imagery, landslides were identified using artificial visual interpretation. Second, 11 landslide-influencing factors were selected, comprising topographic factors (elevation, slope, aspect, curvature), geological environmental factors (strata, distance to faults, distance to waters, distance to roads, normalized difference vegetation index), inducing factors (peak ground acceleration, rainfall), the relationships between the distribution law of landslides and influencing factors were analyzed. Finally, the logistic regression model (LR), the weight of evidence model (WoE), and the weight of evidence- logistic regression (WoE–LR) coupled model were used to evaluate the landslide susceptibility.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141370753","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}
Eyubhan Avci, Mehmet Can Balci, Muhammed Ali Toprak
In this study, the engineering properties of organic soil (OS) stabilised with pozzolanic cement (PC) were investigated. In tests, 10%, 15% and 20% proportions of PC were added to organic soil. Consistency limits, Proctor, unconfined compressive strength (UCS), triaxial (UU), swelling and compressibility tests were performed for OS stabilised with PC. The addition of PC to OS increased the minimum dry density (MDD) and optimum moisture content (OMC) values. The UCS values for OS stabilised with PC increased up to the 56 th day and then there was a reduction in unconfined compressive strength after the 56 th day. The internal friction angle value increased by 26% and the cohesion intercept value increased by 86% for OS stabilised with PC. With the increase in cement content in OS stabilised with PC, the UCS, internal friction angle and cohesion intercept values increased. Swelling of OS stabilised with PC rapidly reduced up to the 10th day and this reduction slowed after the 10th day. The compressibility of OS stabilised with PC increased until the 10 th day and this increase slowed after the 10th day. With the increase in cement content in OS stabilised with PC, swelling and compressibility values reduced. As a result of the study, it appears that pozzolanic cement is an effective stabiliser for organic soil.
在这项研究中，研究人员调查了用硅酸盐水泥（PC）稳定的有机土壤（OS）的工程特性。在试验中，有机土壤中分别添加了 10%、15% 和 20% 比例的 PC。对使用 PC 稳定的有机土壤进行了稠度极限、Proctor、无侧限抗压强度 (UCS)、三轴 (UU)、膨胀性和可压缩性测试。在 OS 中添加 PC 增加了最小干密度（MDD）和最佳含水量（OMC）值。用 PC 稳定的 OS 的 UCS 值在第 56 天前有所增加，但在第 56 天后，无压抗压强度有所下降。用 PC 稳定的 OS 的内摩擦角值增加了 26%，内聚力截距值增加了 86%。随着用 PC 稳定的 OS 中水泥含量的增加，无收缩抗压强度、内摩擦角和内聚力截距值也随之增加。用 PC 稳定的 OS 的膨胀在第 10 天前迅速减小，第 10 天后这种减小速度减慢。用 PC 稳定的 OS 的可压缩性在第 10 天前有所增加，第 10 天后增加速度减慢。随着使用 PC 稳定的 OS 中水泥含量的增加，膨胀值和压缩性都有所降低。研究结果表明，水泥是一种有效的有机土壤稳定剂。
{"title":"Engineering properties of pozzolanic cement-stabilised organic soil","authors":"Eyubhan Avci, Mehmet Can Balci, Muhammed Ali Toprak","doi":"10.1144/qjegh2023-095","DOIUrl":"https://doi.org/10.1144/qjegh2023-095","url":null,"abstract":"\u0000 In this study, the engineering properties of organic soil (OS) stabilised with pozzolanic cement (PC) were investigated. In tests, 10%, 15% and 20% proportions of PC were added to organic soil. Consistency limits, Proctor, unconfined compressive strength (UCS), triaxial (UU), swelling and compressibility tests were performed for OS stabilised with PC. The addition of PC to OS increased the minimum dry density (MDD) and optimum moisture content (OMC) values. The UCS values for OS stabilised with PC increased up to the 56\u0000 th\u0000 day and then there was a reduction in unconfined compressive strength after the 56\u0000 th\u0000 day. The internal friction angle value increased by 26% and the cohesion intercept value increased by 86% for OS stabilised with PC. With the increase in cement content in OS stabilised with PC, the UCS, internal friction angle and cohesion intercept values increased. Swelling of OS stabilised with PC rapidly reduced up to the 10th day and this reduction slowed after the 10th day. The compressibility of OS stabilised with PC increased until the 10\u0000 th\u0000 day and this increase slowed after the 10th day. With the increase in cement content in OS stabilised with PC, swelling and compressibility values reduced. As a result of the study, it appears that pozzolanic cement is an effective stabiliser for organic soil.\u0000","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141270348","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}
Numerical modelling of coaxial deep borehole heat exchangers (DBHE) can be resource-intensive. Simpler, transparent analytical models and nomograms would be valuable to developers and geologists for evaluating thermal output. An analytical computational model by Beier (2020) was used to produce nomograms of geothermal heat yield by systematically varying DBHE depth and rock thermal conductivity, while assuming two generic simplified DBHE designs, a geothermal gradient of 25°C/km and a fluid circulation rate of 5 L/s. Continuous 25-year heat yields from a 1000 m DBHE range from 27.3 to 54.8 kW for thermal conductivities of 1.6 to 3.6 W/m/K. For a 3000 m DBHE, they range from 165 kW to 281 kW. Effective borehole thermal resistance ( R b,eff ) increases strongly as DBHE depth increases, due to internal heat transfer between upflow and downflow elements. Simulations correspond well with results from industry-standard Earth Energy Designer software for shallow 200 m coaxial BHE. They modestly underestimate OpenGeoSys numerical modelled thermal yields by 2-4% for DBHE in the range 1000 to 3000 m depth. Modelled temperature evolution closely approximates an analytical “line heat source” approach, implying that simpler analytical approaches are plausible for DBHE simulation. Future research should focus on methods for forward quantification of R b,eff . Supplementary material: https://doi.org/10.6084/m9.figshare.c.7237887
{"title":"Generic modelling to develop thermal yield nomograms for coaxial deep borehole heat exchangers (DBHE)","authors":"D. Banks, C. Brown, I. Kolo, G. Falcone","doi":"10.1144/qjegh2023-162","DOIUrl":"https://doi.org/10.1144/qjegh2023-162","url":null,"abstract":"\u0000 Numerical modelling of coaxial deep borehole heat exchangers (DBHE) can be resource-intensive. Simpler, transparent analytical models and nomograms would be valuable to developers and geologists for evaluating thermal output. An analytical computational model by Beier (2020) was used to produce nomograms of geothermal heat yield by systematically varying DBHE depth and rock thermal conductivity, while assuming two generic simplified DBHE designs, a geothermal gradient of 25°C/km and a fluid circulation rate of 5 L/s. Continuous 25-year heat yields from a 1000 m DBHE range from 27.3 to 54.8 kW for thermal conductivities of 1.6 to 3.6 W/m/K. For a 3000 m DBHE, they range from 165 kW to 281 kW. Effective borehole thermal resistance (\u0000 \u0000 R\u0000 b,eff\u0000 \u0000 ) increases strongly as DBHE depth increases, due to internal heat transfer between upflow and downflow elements. Simulations correspond well with results from industry-standard Earth Energy Designer software for shallow 200 m coaxial BHE. They modestly underestimate OpenGeoSys numerical modelled thermal yields by 2-4% for DBHE in the range 1000 to 3000 m depth. Modelled temperature evolution closely approximates an analytical “line heat source” approach, implying that simpler analytical approaches are plausible for DBHE simulation. Future research should focus on methods for forward quantification of\u0000 \u0000 R\u0000 b,eff\u0000 \u0000 .\u0000 \u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.7237887\u0000","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141117153","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 paper records the results of a pioneering exploration borehole drilled in 1984 to a depth of 403.84 m in the London Basin and underlying London-Brabant basement high. The key objectives of the project were to measure the equilibrium temperature in the Palaeozoic basement, estimate the temperature gradient after climate impact corrections, and assess the heat flow in the area. From this, estimates of temperature at depths of 2000 m could be made with a view to evaluating potential geothermal resources. From the downhole measurements, a temperature gradient of 16 0 C / km was estimated with a temperatures range between 46 0 C and 51 0 C at 2000 m depth, considered to be consistent with other UK sites where there is no contribution from high heat production granites. The results of the Thamesmead exploration borehole suggested that the geothermal potential of the Devonian and the Palaeozoic basement below London is poor, and no further work was carried out. The work has remained unpublished until now but in view of the current renewed interest in geothermal resources it is appropriate to make the work public. Although the results were not encouraging they do remain as a contribution to the revitalised assessment of geothermal resources in the London area and the UK in general.
本文记录了 1984 年在伦敦盆地和下伏伦敦-布拉班特基底高地钻探至 403.84 米深处的一个开创性勘探钻孔的结果。该项目的主要目标是测量古生代基底的平衡温度，估计气候影响修正后的温度梯度，并评估该地区的热流。由此可以估算出 2000 米深处的温度，以评估潜在的地热资源。根据井下测量结果，估计温度梯度为 16 0 C/公里，2000 米深处的温度范围在 46 0 C 至 51 0 C 之间，这与英国其他没有高产热量花岗岩的地点一致。泰晤士河畔勘探钻孔的结果表明，伦敦以下泥盆纪和古生代基底的地热潜力很低，因此没有开展进一步的工作。 这项工作直到现在仍未发表，但鉴于目前人们对地热资源重新产生了兴趣，公开这项工作是合适的。尽管结果并不令人鼓舞，但它仍然为重新评估伦敦地区乃至整个英国的地热资源做出了贡献。
{"title":"Record of a Pioneering Geothermal Borehole in London","authors":"J. C. Gutmanis, A.J. Beswick","doi":"10.1144/qjegh2023-155","DOIUrl":"https://doi.org/10.1144/qjegh2023-155","url":null,"abstract":"\u0000 This paper records the results of a pioneering exploration borehole drilled in 1984 to a depth of 403.84 m in the London Basin and underlying London-Brabant basement high. The key objectives of the project were to measure the equilibrium temperature in the Palaeozoic basement, estimate the temperature gradient after climate impact corrections, and assess the heat flow in the area. From this, estimates of temperature at depths of 2000 m could be made with a view to evaluating potential geothermal resources. From the downhole measurements, a temperature gradient of 16\u0000 0\u0000 C / km was estimated with a temperatures range between 46\u0000 0\u0000 C and 51\u0000 0\u0000 C at 2000 m depth, considered to be consistent with other UK sites where there is no contribution from high heat production granites. The results of the Thamesmead exploration borehole suggested that the geothermal potential of the Devonian and the Palaeozoic basement below London is poor, and no further work was carried out.\u0000 \u0000 The work has remained unpublished until now but in view of the current renewed interest in geothermal resources it is appropriate to make the work public. Although the results were not encouraging they do remain as a contribution to the revitalised assessment of geothermal resources in the London area and the UK in general. ","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141118726","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}
D. B. Walls, D. Banks, Y. Kremer, A. J. Boyce, N. M. Burnside
Water within flooded coal mines can be abstracted via boreholes or shafts, where heat can be extracted from (or rejected to) it to satisfy surface heating (or cooling) demands. Following use, water can be reinjected to the mine workings, or discharged to a surface water receptor. Four criteria have been applied, using ArcGIS, to datasets describing mine workings and mine water below the Midland Valley of Scotland, to provide an initial screening tool for suitability for mine water geothermal energy exploitation. The criteria are: (i) presence of two or more worked coal seams below site, (ii) absence of potentially unstable shallow (<30 m) workings, (iii) depth to mine water piezometric head <60 m, (iv) depth of coal mine workings <250 m. The result is the Mine Water Geothermal Resource Atlas for Scotland (MiRAS). MiRAS suggests that a total area of 370 km 2 is “optimal” for mine water geothermal development across 19 local authority areas, with greatest coverage in North Lanarkshire. This result should not be taken to suggest that mine water geothermal potential does not exist at locations outside the identified “optimal” footprint. The MiRAS does not preclude the necessity for specialist engineering and geological input during full feasibility study. Thematic collection: This article is part of the Mine Water Energy collection available at: https://www.lyellcollection.org/topic/collections/mine-water-energy Supplementary material: https://doi.org/10.6084/m9.figshare.c.7235866
{"title":"GIS analysis for the selection of optimal sites for mine water geothermal energy application: a case study of Scotland's mining regions","authors":"D. B. Walls, D. Banks, Y. Kremer, A. J. Boyce, N. M. Burnside","doi":"10.1144/qjegh2023-050","DOIUrl":"https://doi.org/10.1144/qjegh2023-050","url":null,"abstract":"\u0000 Water within flooded coal mines can be abstracted via boreholes or shafts, where heat can be extracted from (or rejected to) it to satisfy surface heating (or cooling) demands. Following use, water can be reinjected to the mine workings, or discharged to a surface water receptor. Four criteria have been applied, using ArcGIS, to datasets describing mine workings and mine water below the Midland Valley of Scotland, to provide an initial screening tool for suitability for mine water geothermal energy exploitation. The criteria are: (i) presence of two or more worked coal seams below site, (ii) absence of potentially unstable shallow (<30 m) workings, (iii) depth to mine water piezometric head <60 m, (iv) depth of coal mine workings <250 m. The result is the Mine Water Geothermal Resource Atlas for Scotland (MiRAS). MiRAS suggests that a total area of 370 km\u0000 2\u0000 is “optimal” for mine water geothermal development across 19 local authority areas, with greatest coverage in North Lanarkshire. This result should not be taken to suggest that mine water geothermal potential does not exist at locations outside the identified “optimal” footprint. The MiRAS does not preclude the necessity for specialist engineering and geological input during full feasibility study.\u0000 \u0000 \u0000 Thematic collection:\u0000 This article is part of the Mine Water Energy collection available at:\u0000 https://www.lyellcollection.org/topic/collections/mine-water-energy\u0000 \u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.7235866\u0000","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141122810","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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