Influence radius of a pumping well is a crucial parameter for hydrogeologists and engineers. Knowing the radius of influence for a designed drawdown enables one to calculate the pumping rate required to layout a proje...Influence radius of a pumping well is a crucial parameter for hydrogeologists and engineers. Knowing the radius of influence for a designed drawdown enables one to calculate the pumping rate required to layout a project foundation that may need lowering of groundwater level to a certain depth due to dewatering operation. In addition, this is important for hydrogeologists to determine ground water contamination flow paths and contributing recharge area for domestic water supply and aquifer management purposes. Empirical formulas that usually neglect vital parameters to determine the influence radius accurately have been traditionally utilized due to lack of adequate methods. In this study, a physically based method, which incorporates aquifer hydraulic gradient for determining the influence radius of a pumping well in steady-state flow condition, was developed. It utilizes Darcy and Dupuit laws to calculate the influence radius, where Darcy’s law and Dupuit equation, in steady-state condition, represent the inflow and the outflow of the pumping well, respectively. In an untraditional manner, this method can be also used to determine aquifer hydraulic conductivity as an alternative to other pumping test methods with high degree of accuracy. The developed method is easy to use;where a simple mathematical calculator may be used to calculate the influence radius and the pumping rate or hydraulic conductivity. By comparing the results from this method with the MODFLOW numerical model outputs with different simulated scenarios, it is realized that this method is much superior and more advantageous than other commonly used empirical methods.展开更多
Mining-induced surface subsidence often causes buried oil–gas pipelines deform,and the potential leakage risk can pose a safety hazard.In this work,a novel model for predicting the influence range of potential leakag...Mining-induced surface subsidence often causes buried oil–gas pipelines deform,and the potential leakage risk can pose a safety hazard.In this work,a novel model for predicting the influence range of potential leakage risk from deformed pipelines was developed.First,the pipe instability deformation limit was corrected by the multi-indicator optimized screening method proposed in this paper.Then,the leakage risk influence radius of the pipe segment was defined by the failure probability.Next,the pipe segment'deformation and strength were assessed sequentially using the ratio and point methods.Combining the fuzzy logic inference method with the assessment results as input variable,and the failure probabilities as output variable,a quantitative assessment model for the pipeline leakage risk was established.Accordingly,the risk range and level of adjacent coal mines and surfaces were divided,and the verification method and forward countermeasures were proposed.Finally,an engineering case was used for analysis and verification.The results show that the gas pipeline with 650 m length was divided into seven regions and four risk levels.The influence radius of the risk levels from low to high were 12.75 m,25.5 m,38.25 m,and 51 m,and the influence widths on the surface were 25.28 m,49.84 m,76.34 m,and 101.84 m,correspondingly.The nearest distances from the risk area to the mine and village were 212.65 m and 329.08 m.The assessment of potentially threatened areas is significantly simplified by the assessment model combined with pipeline deformation,which has great practical importance for risk management and disaster prevention in adjacent space.展开更多
Due to its large heat transfer area and stable thermal performance,the middledeep coaxial borehole heat exchanger(CBHE)has become one of the emerging technologies to extract geothermal energy.In this paper,a numerical...Due to its large heat transfer area and stable thermal performance,the middledeep coaxial borehole heat exchanger(CBHE)has become one of the emerging technologies to extract geothermal energy.In this paper,a numerical modeling on a three-dimensional unsteady heat transfer model of a CBHE was conducted by using software FEFLOW,in which the model simulation was compared with the other studies and was validated with experimental data.On this basis,a further simulation was done in respect of assessing the influencing factors of thermal extraction performance and thermal influence radius of the CBHE.The results show that the outlet temperature of the heat exchanger decreases rapidly at the initial stage,and then tended to be stable;and the thermal influence radius increases with the increase of borehole depth.The heat extraction rate of the borehole increases linearly with the geothermal gradient.Rock heat capacity has limited impact on the heat extraction rate,but has a great influence on the thermal influence radius of the CBHE.When there is groundwater flow in the reservoir,the increase of groundwater velocity will result in the rise of both outlet temperature and heat extraction rate.The heat affected zone extends along with the groundwater flow direction;and its influence radius is increasing along with flow velocity.In addition,the material of the inner pipe has a significant effect on the heat loss in the pipe,so it is recommended that the material with low thermal conductivity should be used if possible.展开更多
Based on the simulation of a marine ecosystem dynamical model in the Bohai Sea, the Yellow Sea and the East China Sea, chlorophyll data are assimilated to study the spatially varying control parameters （CPs） by usin...Based on the simulation of a marine ecosystem dynamical model in the Bohai Sea, the Yellow Sea and the East China Sea, chlorophyll data are assimilated to study the spatially varying control parameters （CPs） by using the adjoint method. In this study, the CPs at some grid points are selected as the independent CPs, while the CPs at other grid points can be obtained through linear interpolation with the independent CPs. The independent CPs are uniformly selected from each 30′ × 30′area, and we confirm that the optimal influence radius is 1.2° by a twin experiment. In the following experiments, when only the maximum growth rate of phytoplankton （Vm） is estimated by two given types of spatially varying CPs, the mean relative errors of Vm are 1.22% and 0.94% while the decrease rates of the mean error of chlorophyll in the surface are 94.6% and 95.8%, respectively. When the other four CPs are estimated respectively, the results are also satisfactory, which indicates that the adjoint method has a strong ability of optimizing the prescribed CP with spatial variations. However, when all these five most important CPs are estimated simultaneously, the collocation of the changing trend of each parameter influences the estimation results remarkably. Only when the collocation of the changing trend of each parameter is consistent with the ecological mechanisms which influence the growth of the phytoplankton in marine ecosystem, could the five most important CPs be estimated more accurately.展开更多
Air sparging(AS) is an emerging method to remove VOCs from saturated soils and groundwater. Air sparging performance highly depends on the air distribution resulting in the aquifer. In order to study gas flow characte...Air sparging(AS) is an emerging method to remove VOCs from saturated soils and groundwater. Air sparging performance highly depends on the air distribution resulting in the aquifer. In order to study gas flow characterization, a two-dimensional experimental chamber was designed and installed. In addition, the method by using acetylene as the tracer to directly image the gas distribution results of AS process has been put forward. Experiments were performed with different injected gas flow rates. The gas flow patterns were found to depend significantly on the injected gas flow rate, and the characterization of gas flow distributions in porous media was very different from the acetylene tracing study. Lower and higher gas flow rates generally yield more irregular in shape and less effective gas distributions.展开更多
The present study has been undertaken to depict spatial distribution of different aquifer parameters in the eastern part of Kushtia district through a detailed hydrogeological survey. For this investigation, 119 litho...The present study has been undertaken to depict spatial distribution of different aquifer parameters in the eastern part of Kushtia district through a detailed hydrogeological survey. For this investigation, 119 lithologs and 92 pumping test data have been used. These data have been processed, analyzed, interpreted and krigged for the spatial assessment of the aquifer properties viz. transmissivity, hydraulic conductivity, hydraulic diffusivity, specific yield, radius of influence, and specific drawdown. It is seen from the investigation that the transmissivity and hydraulic conductivity values obtained from the pumping tests of the wells are varying from 1811 m<sup>2</sup>/day to 2568 m<sup>2</sup>/day and 32.5 m/day and 61.5 m/day respectively, the hydraulic diffusivity being ranging from 181,143 m<sup>2</sup>/day to 256,788 m<sup>2</sup>/day. The estimated specific yield of 17.97% - 23.46% supports that the area is dominated with coarse grained sands. This study reveals that the distribution of deep tube wells in the area are not within the radius of influence (638 - 760 m) each other, but few shallow and hand tube wells existed within the radius of influence. The estimated specific draw down is varying from 57 m/cumec to 126.1 m/cumec. From the overall analysis, it is found that the area is favorable for groundwater exploration.展开更多
In general, the content of this study is aimed at presenting a comparative analysis of the hydrogeological results of three underground sources. The points or sources of analysis are the Dolores 01, Dolores 02 and Mec...In general, the content of this study is aimed at presenting a comparative analysis of the hydrogeological results of three underground sources. The points or sources of analysis are the Dolores 01, Dolores 02 and Mecatepillo wells, which are registered at the following coordinates: East 610561, North 1292576, East 610234, North 1293090, East 611482, North 1293881, respectively, according to the UTM WGS system 84 Zone 16N, the analysis is done with a basin approach in the Nandaime-Rivas aquifer. According to the above, bibliographic resources have been consulted that help to further understand the comparative criteria such as transmissibility, storage coefficient, a radius of influence and thickness of the aquifer, providing complementary and additional information.展开更多
Microbial electrochemical technologies(MET)can remove a variety of organic and inorganic pollutants from contaminated groundwater.However,despite significant laboratory-scale successes over the past decade,field-scale...Microbial electrochemical technologies(MET)can remove a variety of organic and inorganic pollutants from contaminated groundwater.However,despite significant laboratory-scale successes over the past decade,field-scale applications remain limited.We hypothesize that enhancing the electrochemical conductivity of the soil surrounding electrodes could be a groundbreaking and cost-effective alternative to deploying numerous high-surface-area electrodes in short distances.This could be achieved by injecting environmentally safe iron-or carbon-based conductive(nano)particles into the aquifer.Upon transport and deposition onto soil grains,these particles create an electrically conductive zone that can be exploited to control and fine-tune the delivery of electron donors or acceptors over large distances,thereby driving the process more efficiently.Beyond extending the radius of influence of electrodes,these diffuse electro-conductive zones(DECZ)could also promote the development of syntrophic anaerobic communities that degrade contaminants via direct interspecies electron transfer(DIET).In this review,we present the state-of-the-art in applying conductive materials for MET and DIET-based applications.We also provide a comprehensive overview of the physicochemical properties of candidate electrochemically conductive materials and related injection strategies suitable for field-scale implementation.Finally,we illustrate and critically discuss current and prospective electrochemical and geophysical methods for measuring soil electronic conductivitydboth in the laboratory and in the fielddbefore and after injection practices,which are crucial for determining the extent of DECZ.This review article provides critical information for a robust design and in situ implementation of groundwater electro-bioremediation processes.展开更多
文摘Influence radius of a pumping well is a crucial parameter for hydrogeologists and engineers. Knowing the radius of influence for a designed drawdown enables one to calculate the pumping rate required to layout a project foundation that may need lowering of groundwater level to a certain depth due to dewatering operation. In addition, this is important for hydrogeologists to determine ground water contamination flow paths and contributing recharge area for domestic water supply and aquifer management purposes. Empirical formulas that usually neglect vital parameters to determine the influence radius accurately have been traditionally utilized due to lack of adequate methods. In this study, a physically based method, which incorporates aquifer hydraulic gradient for determining the influence radius of a pumping well in steady-state flow condition, was developed. It utilizes Darcy and Dupuit laws to calculate the influence radius, where Darcy’s law and Dupuit equation, in steady-state condition, represent the inflow and the outflow of the pumping well, respectively. In an untraditional manner, this method can be also used to determine aquifer hydraulic conductivity as an alternative to other pumping test methods with high degree of accuracy. The developed method is easy to use;where a simple mathematical calculator may be used to calculate the influence radius and the pumping rate or hydraulic conductivity. By comparing the results from this method with the MODFLOW numerical model outputs with different simulated scenarios, it is realized that this method is much superior and more advantageous than other commonly used empirical methods.
基金funded by the National Natural Science Foundation of China(52225402 and 51874312)the Major scientific and technological innovation project of Shandong Province(2019SDZY01 and 2019SDZY02).
文摘Mining-induced surface subsidence often causes buried oil–gas pipelines deform,and the potential leakage risk can pose a safety hazard.In this work,a novel model for predicting the influence range of potential leakage risk from deformed pipelines was developed.First,the pipe instability deformation limit was corrected by the multi-indicator optimized screening method proposed in this paper.Then,the leakage risk influence radius of the pipe segment was defined by the failure probability.Next,the pipe segment'deformation and strength were assessed sequentially using the ratio and point methods.Combining the fuzzy logic inference method with the assessment results as input variable,and the failure probabilities as output variable,a quantitative assessment model for the pipeline leakage risk was established.Accordingly,the risk range and level of adjacent coal mines and surfaces were divided,and the verification method and forward countermeasures were proposed.Finally,an engineering case was used for analysis and verification.The results show that the gas pipeline with 650 m length was divided into seven regions and four risk levels.The influence radius of the risk levels from low to high were 12.75 m,25.5 m,38.25 m,and 51 m,and the influence widths on the surface were 25.28 m,49.84 m,76.34 m,and 101.84 m,correspondingly.The nearest distances from the risk area to the mine and village were 212.65 m and 329.08 m.The assessment of potentially threatened areas is significantly simplified by the assessment model combined with pipeline deformation,which has great practical importance for risk management and disaster prevention in adjacent space.
基金This study was supported by China Geological Survey Program(No.DD20160190 and DD20190128)Natural Science Foundation of Hebei Province(No.E2020202065).
文摘Due to its large heat transfer area and stable thermal performance,the middledeep coaxial borehole heat exchanger(CBHE)has become one of the emerging technologies to extract geothermal energy.In this paper,a numerical modeling on a three-dimensional unsteady heat transfer model of a CBHE was conducted by using software FEFLOW,in which the model simulation was compared with the other studies and was validated with experimental data.On this basis,a further simulation was done in respect of assessing the influencing factors of thermal extraction performance and thermal influence radius of the CBHE.The results show that the outlet temperature of the heat exchanger decreases rapidly at the initial stage,and then tended to be stable;and the thermal influence radius increases with the increase of borehole depth.The heat extraction rate of the borehole increases linearly with the geothermal gradient.Rock heat capacity has limited impact on the heat extraction rate,but has a great influence on the thermal influence radius of the CBHE.When there is groundwater flow in the reservoir,the increase of groundwater velocity will result in the rise of both outlet temperature and heat extraction rate.The heat affected zone extends along with the groundwater flow direction;and its influence radius is increasing along with flow velocity.In addition,the material of the inner pipe has a significant effect on the heat loss in the pipe,so it is recommended that the material with low thermal conductivity should be used if possible.
基金The State Ministry of Science and Technology of China under contract No. 2007AA09Z118the National Natural Science Foundation of China under contract No. 41076006the Ministry of Education’s 111 Project under contract No. B07036
文摘Based on the simulation of a marine ecosystem dynamical model in the Bohai Sea, the Yellow Sea and the East China Sea, chlorophyll data are assimilated to study the spatially varying control parameters （CPs） by using the adjoint method. In this study, the CPs at some grid points are selected as the independent CPs, while the CPs at other grid points can be obtained through linear interpolation with the independent CPs. The independent CPs are uniformly selected from each 30′ × 30′area, and we confirm that the optimal influence radius is 1.2° by a twin experiment. In the following experiments, when only the maximum growth rate of phytoplankton （Vm） is estimated by two given types of spatially varying CPs, the mean relative errors of Vm are 1.22% and 0.94% while the decrease rates of the mean error of chlorophyll in the surface are 94.6% and 95.8%, respectively. When the other four CPs are estimated respectively, the results are also satisfactory, which indicates that the adjoint method has a strong ability of optimizing the prescribed CP with spatial variations. However, when all these five most important CPs are estimated simultaneously, the collocation of the changing trend of each parameter influences the estimation results remarkably. Only when the collocation of the changing trend of each parameter is consistent with the ecological mechanisms which influence the growth of the phytoplankton in marine ecosystem, could the five most important CPs be estimated more accurately.
基金The National Natural Science Foundation of China(No. 20276048)
文摘Air sparging(AS) is an emerging method to remove VOCs from saturated soils and groundwater. Air sparging performance highly depends on the air distribution resulting in the aquifer. In order to study gas flow characterization, a two-dimensional experimental chamber was designed and installed. In addition, the method by using acetylene as the tracer to directly image the gas distribution results of AS process has been put forward. Experiments were performed with different injected gas flow rates. The gas flow patterns were found to depend significantly on the injected gas flow rate, and the characterization of gas flow distributions in porous media was very different from the acetylene tracing study. Lower and higher gas flow rates generally yield more irregular in shape and less effective gas distributions.
文摘The present study has been undertaken to depict spatial distribution of different aquifer parameters in the eastern part of Kushtia district through a detailed hydrogeological survey. For this investigation, 119 lithologs and 92 pumping test data have been used. These data have been processed, analyzed, interpreted and krigged for the spatial assessment of the aquifer properties viz. transmissivity, hydraulic conductivity, hydraulic diffusivity, specific yield, radius of influence, and specific drawdown. It is seen from the investigation that the transmissivity and hydraulic conductivity values obtained from the pumping tests of the wells are varying from 1811 m<sup>2</sup>/day to 2568 m<sup>2</sup>/day and 32.5 m/day and 61.5 m/day respectively, the hydraulic diffusivity being ranging from 181,143 m<sup>2</sup>/day to 256,788 m<sup>2</sup>/day. The estimated specific yield of 17.97% - 23.46% supports that the area is dominated with coarse grained sands. This study reveals that the distribution of deep tube wells in the area are not within the radius of influence (638 - 760 m) each other, but few shallow and hand tube wells existed within the radius of influence. The estimated specific draw down is varying from 57 m/cumec to 126.1 m/cumec. From the overall analysis, it is found that the area is favorable for groundwater exploration.
文摘In general, the content of this study is aimed at presenting a comparative analysis of the hydrogeological results of three underground sources. The points or sources of analysis are the Dolores 01, Dolores 02 and Mecatepillo wells, which are registered at the following coordinates: East 610561, North 1292576, East 610234, North 1293090, East 611482, North 1293881, respectively, according to the UTM WGS system 84 Zone 16N, the analysis is done with a basin approach in the Nandaime-Rivas aquifer. According to the above, bibliographic resources have been consulted that help to further understand the comparative criteria such as transmissibility, storage coefficient, a radius of influence and thickness of the aquifer, providing complementary and additional information.
基金support under the National Recovery and Resilience Plan(NRRP)Mission 4,Component 2,Investment 1.1,Call for tender No.104 published on February 2,2022 by the Italian Ministry of University and Research(MUR)+2 种基金funded by the European Union e Next GenerationEUe Project Title SteeRing GroundwatEr Electro-bioremediAtion with ConducTIVe ParticlEs(REACTIVE)e CUP:B53D23018110006-Grant Assignment Decree No.1048 adopted on July 14,2023 by the Italian Ministry of University and Research(MUR).UM acknowledges Villum Foundation(grant n.VIL50414)the Grundfos Foundation(grant n.2017-025)LP and GC acknowledge The Geosciences for Sustainable Development project(Budget Ministero dell'Universita e della Ricerca-Dipartimenti di Eccellenza 2023-2027,C93C23002690001).
文摘Microbial electrochemical technologies(MET)can remove a variety of organic and inorganic pollutants from contaminated groundwater.However,despite significant laboratory-scale successes over the past decade,field-scale applications remain limited.We hypothesize that enhancing the electrochemical conductivity of the soil surrounding electrodes could be a groundbreaking and cost-effective alternative to deploying numerous high-surface-area electrodes in short distances.This could be achieved by injecting environmentally safe iron-or carbon-based conductive(nano)particles into the aquifer.Upon transport and deposition onto soil grains,these particles create an electrically conductive zone that can be exploited to control and fine-tune the delivery of electron donors or acceptors over large distances,thereby driving the process more efficiently.Beyond extending the radius of influence of electrodes,these diffuse electro-conductive zones(DECZ)could also promote the development of syntrophic anaerobic communities that degrade contaminants via direct interspecies electron transfer(DIET).In this review,we present the state-of-the-art in applying conductive materials for MET and DIET-based applications.We also provide a comprehensive overview of the physicochemical properties of candidate electrochemically conductive materials and related injection strategies suitable for field-scale implementation.Finally,we illustrate and critically discuss current and prospective electrochemical and geophysical methods for measuring soil electronic conductivitydboth in the laboratory and in the fielddbefore and after injection practices,which are crucial for determining the extent of DECZ.This review article provides critical information for a robust design and in situ implementation of groundwater electro-bioremediation processes.
