Deep-seated potassium-rich brines were identified in the Jiangling Basin,South China.Although magmatichydrothermal sources have been proposed,the relationship between brine-type potash mineralization and volcanism rem...Deep-seated potassium-rich brines were identified in the Jiangling Basin,South China.Although magmatichydrothermal sources have been proposed,the relationship between brine-type potash mineralization and volcanism remains unclear.In this study,U-Pb geochronology,geochemistry,fluid inclusion and C-O isotopic compositions of hydrothermal vein minerals in the Jiangling Basin are examined.Laser ablation U-Pb dating of calcite veins indicates that the ages are slightly younger than the formation age of the Balingshan basalt.Fluid inclusions in hydrothermal minerals show medium–low homogenization temperatures(160–220℃)and low salinities(0.14 to 4.9 wt%NaCl eqv.)and densities(0.882–0.944 g/cm^(3)).The liquid compositions of fluid inclusions in calcite veins from sedimentary strata have higher contents of potassium,compared with those from basalt.The coupled negativeδ^(13)CPDB(-10.3‰to-8.0‰)and positiveδ^(18)OSMOW(17.4‰to 20.7‰)values imply that calcite precipitation resulted from CO_(2)degassing of the basaltic magmatic fluids,as indicated by the gas composition of these inclusions in hydrothermal minerals.Rare earth element patterns indicate that water-rock interaction between hydrothermal fluids and sedimentary wall rocks contributed to the calcite precipitation in sedimentary strata.It is proposed that high-temperature water-rock interaction between magmatic fluids and sedimentary strata resulted in the potassium enrichment in fluids,interpreted as one of the sources of potassium-rich brines in the Jiangling Basin.展开更多
This paper presents results of an experimental study to characterize the law of mineral change of fallen rock in coal mine groundwater reservoir ant its influence on water quality.The minerals of the underground reser...This paper presents results of an experimental study to characterize the law of mineral change of fallen rock in coal mine groundwater reservoir ant its influence on water quality.The minerals of the underground reservoir of Daliuta Coal Mine is taken as the research object.Simulation experiments were designed and conducted to simulate water–rock action in the laboratory.The mineral composition was analyzed by X-ray diffractometer(XRD),the surface morphology of the mineral was analyzed by scanning electron microscope(SEM),and the specific surface area,total pore volume and average pore diameter of the mineral were measured by fast specific surface/pore analyzer(BET).The experimental results show that the sandstone and mudstone in the groundwater reservoir of Daliuta Coal Mine account for 70%and 30%,respectively.The pore diameter is 15.62–17.55 nm,and pore volume is 0.035 cc/g.Its pore structure is a key factor in the occurrence of water–rock interaction.According to the water–rock simulation experiment,the quartz content before the water–rock action is about 34.28%,the albite is about 21.84%,the feldspar is about 17.48%,and the kaolinite is about 8.00%.After the water–rock action,they are 36.14%,17.78%,11.62%,and 16.75%,respectively.The content of albite and orthoclase is reduced while the content of kaolinite is increased,that is,the Na+content becomes higher,and the Ca2+and Mg2+contents become lower.This research builds a good theoretical foundation for revealing the role of water and rock in underground coal reservoirs.展开更多
The aim of this study is to evaluate the hydrogeochemical characteristics and water environmental quality of shallow groundwater in the Suxian mining area of Huaibei coalfield,China.The natural formation process of sh...The aim of this study is to evaluate the hydrogeochemical characteristics and water environmental quality of shallow groundwater in the Suxian mining area of Huaibei coalfield,China.The natural formation process of shallow groundwater in Suxian is explored using Piper trilinear charts and Gibbs diagrams,and by examining the ratios between the major ions.United States Salinity Laboratory(USSL)charts,Wilcox diagrams,and the water quality index(WQI)are further employed to quantify the differences in water quality.The results reveal that the main hydrochemical facies of groundwater are HC03-Ca,and that silicate dissolution is the main factor controlling the ion content in shallow groundwater.The USSL charts and Wilcox diagrams show that most of the water samples would be acceptable for use in irrigation systems.The WQI results for each water sample are compared and analyzed,and the quality of groundwater samples around collapse ponds is found to be relatively poor.展开更多
Based on the analysis of element correlation,the Gibbs diagram,hydro-geochemical ion ratios,isoline maps of groundwater and soil,and change patterns of strontium content after normalization,the study examines water-ro...Based on the analysis of element correlation,the Gibbs diagram,hydro-geochemical ion ratios,isoline maps of groundwater and soil,and change patterns of strontium content after normalization,the study examines water-rock interaction of shallow groundwater in Dingtao area.The results suggest that strontium in the study area mainly comes from waterrock interactions,and the strata interacting with groundwater are the top of Quaternary and Neogene.The element correlation analysis shows that the formation of strontium-rich groundwater is sufficiently affected by sulfate and carbonate.The Gibbs diagram suggests that the chemical composition of groundwater is mainly influenced by water-rock interactions,accompanied by evaporation crystallization.c(Ca2++Mg2+)/c(HCO3-+SO42-)reflects that the main reactions in the groundwater system is weathering dissolution of carbonate and sulfate,and ion exchange takes place.c(Na+)/c(Cl-)indicates that Na+in groundwater may have waterrock interactions with rocks it flows through.c(Cl-)/c(Ca2+)indicates that the hydrodynamic condition in the pumping well is poor and the water circulation is slow.The study examines the macro isoline map change patterns,correlation curves of change of strontium content in groundwater and shallow soil,and correlation curves of change of strontium content in groundwater,shallow soil,and deep soil.The results suggest that the strontium content in the study area has the same change pattern in groundwater and in soil,which further indicates that strontium in the study area comes from water-rock interactions.展开更多
This study focuses on the geochemical and bacteriological investigation of surface and ground water in the Bamoun plateau (Western-Cameroon). During the period from September 2013 to August 2014, 71 samples were colle...This study focuses on the geochemical and bacteriological investigation of surface and ground water in the Bamoun plateau (Western-Cameroon). During the period from September 2013 to August 2014, 71 samples were collected from two springs, one borehole, four wells and the Nchi stream for analysis of major elements. In order to obtain the characteristics of the various species of bacteria, 7 samples were selected. The analytical method adopted for this study is the conventional hydrochemical technic and multivariate statistical analysis, coupled with the hydrogeochemical modelling. The results revealed that, water from the zone under study are acidic to basic, very weakly to weakly mineralized. Four types of water were identified: 1) CaMg-HCO<sub>3</sub>;2) CaMg-Cl-SO<sub>4</sub>;3) NaCl-SO<sub>4</sub> and 4) NaK-HCO<sub>3</sub>. The major elements were all listed in the World Health Organization guidelines for drinking water quality, except for nitrates which was found at a concentration > 50 mg /l <span style="white-space:nowrap;">NO<sup>-</sup><sub style="margin-left:-7px;">3</sub> </span>in the borehole F401. As for the hydrobiological aspect, the entire sample contained all the bacteriological species except for spring S301 and well P401. According to the hydrogeochemical modelling, the Gibbs model and multivariate statistical tests, the quality of surface and ground water of the Foumban locality is influenced by two important factors: 1) the natural factors characterized by the water-rock interaction, evapotranspiration/crystallization, 2) the anthropogenic factors such as: uncontrolled discharges of liquid and solid effluents of all kinds and without any prior treatment within the ground and the strong urbanization accompanied by lack of sanitation and insufficient care.展开更多
The instability of underground spaces in abandoned coal mines with water-immersed rocks is one of the main hazards hindering the geothermal energy use and ecological restoration of post-mining areas.This study conduct...The instability of underground spaces in abandoned coal mines with water-immersed rocks is one of the main hazards hindering the geothermal energy use and ecological restoration of post-mining areas.This study conducted graded cyclic loading–unloading tests of fve groups of sandstone samples with diferent water contents.The evolution of input,elastic,dissipated,damping,and plastic energies were explored,considering the damping efect.The normalized plastic energy serves to characterize the damage evolution of sandstone samples,whose failure characteristics were analyzed from both the macroscopic and microscopic perspectives.X-ray difraction technique and scanning electron microscopy were used to reveal the softening mechanism of sandstone.The results show that under graded cyclic loading,input energy,elastic energy,and dissipated energy all increase gradually,and the fraction of elastic energy increases gradually at frst and then tends to stabilize.The variation in the fraction of dissipated energy is opposite to that of elastic energy.In each cycle,the input energy is stored primarily in the form of elastic energy,whereas the dissipated energy is used primarily to overcome the damping of sandstone.When the normalized number of cycles approached unity,the plastic energy fraction sharply increases,while that of the dampening energy drops abruptly.With increasing water content,the efect of pore water on the lubrication,the water wedge,and dissolution of mineral particles becomes more obvious,reducing the elastic-storage limit of sandstone,meanwhile the sandstone damage factor increases signifcantly under the same cycle and the failure mode changes from brittle to ductile.展开更多
Umm Er Radhuma Aquifer (UER) is the most important groundwater aquifer in Saudi Arabia, extending over 1.6 M<span style="font-size:10.5pt;font-family:;" "=""><span style="color:#...Umm Er Radhuma Aquifer (UER) is the most important groundwater aquifer in Saudi Arabia, extending over 1.6 M<span style="font-size:10.5pt;font-family:;" "=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span></span></span>km<sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> in the eastern part of the Arabian Peninsula, forming the main aquifer throughout the Rub’ Al-Khali (RAK). </span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">Groundwater salinity increased from west to east, reaching more than 27,000 mg/L near the border with the United Arab Emirates, where a Na</span><sup><span style="font-family:Verdana;">+</span></sup><span style="font-family:Verdana;">-Ca</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;">Cl<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><span style="font-family:Verdana;">-<img src="Edit_c1bbc858-a8a7-45ca-be57-e2bb456cbddb.bmp" alt="" /></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> </span></span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">water type dominated. Gibbs diagrams indicated that the dissolution/precipitation of carbonates and evaporation/precipitation of minerals, especially anhydrite, gypsum, and halite account for the solutes and salinity in groundwater. Most of the samples plot above the 1:1 line of (Ca</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;"> + Mg</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;">) against <img src="Edit_5405b197-c8d5-436d-8648-dd95afefb8e6.bmp" alt="" /></span></span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">, indicating other sources of Ca</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;"> and Mg</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;"> in the groundwater along with dolomite and calcium carbonate minerals. Phreeqc model indicated that the main clay minerals are kaolinite and gibbsite which had major effect on the cation exchange process as indicated by the Chloro-Alkaline index (CAI), where most of groundwater samples had values greater than zero which indicated the occurrence of reverse ion exchange between the groundwater and its host aquifer. The water type Na</span><sup><span style="font-family:Verdana;">+</span></sup><span style="font-family:Verdana;">-Ca</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;">Cl</span><sup><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span></sup><span style="font-family:Verdana;">-<img src="Edit_e8c17a28-24a8-4e14-a615-24c0e0817331.bmp" alt="" /></span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">dominated in the eastern part of the aquifer as the anaerobic conditions prevailed and the reduction of sulphate took place.</span></span></span></span>展开更多
For the sake of mine water drainage and sustainable groundwater protection,the new approach of mine water deep geological storage(MWDGS)is highly necessary to save water resources in the semi-arid region of China.Howe...For the sake of mine water drainage and sustainable groundwater protection,the new approach of mine water deep geological storage(MWDGS)is highly necessary to save water resources in the semi-arid region of China.However,up to now,little academic research has been done on mine water geological storage.Given this situation,the hydrogeological feasibility of MWDGS was explored in Baotashan coarse sandstone(BCS)of Jurassic measure in Ordos Basin.The results show that the white-gray BCS with a fragile skeleton of quartz(41.4%),feldspar(21.1%),and clay minerals(16.4%)provides the potential variable-void for mine water;and its hydro-chemical type of BCS aquifer is CO_(3)-Na and Cl-Na.As the burial depth increases,the strong alkaline groundwater is in stagnant and poor recharge-runoff-discharge condition.The lab test shows that the pores whose diameter is over 10μm could be treated as the main storage of mine water;and the effective porosity varies from 1.36%to 3.46%.When mine water is injected,the strong hydrodynamics of mine water storage would change the permeability significantly and about 0.201%soluble solids would be dissolved.Partial clay minerals obstruct the pores and induce the saturated phase of high permeability to evolve into steady phase of lower permeability.Under the condition of nonhydraulic fracturing during continuous storage,the heterogeneous anisotropic medium obtained by Transition PRObability GeoStatistics(TPROGS)shows that the capacity of BCS aquifer is 0.455 to 1.226Mm^(3)for 1 km^(2)in the study area.The simulation shows that the groundwater mound in well-scale and mine-scale would be formed.The groundwater quality characteristics of“Three Zone”would occur around and gradually drop to approximate the original brine within 10 years.The hydrogeological feasibility reveals that this approach is useful for the well design and groundwater environment management during the mine water deep geological storage project in the Ordos basin.展开更多
Hydrogeological investigation of groundwater has been performed within Kasra- Nukhaib district (west Iraq). The physicochemical analyses of the groundwater samples collected from Um Erdhuma-Tayarat aquifer are used in...Hydrogeological investigation of groundwater has been performed within Kasra- Nukhaib district (west Iraq). The physicochemical analyses of the groundwater samples collected from Um Erdhuma-Tayarat aquifer are used in determination of hydrogeochemical processes, hydrochemical facies, hydrochemical ratio, and saturation indices supported by phreeqc software. The monitoring network of groundwater quality consists of twelve physiochemical variables in twenty four water wells were determined, aiming to examine the hydrogeo-chemical phenomena which are benefit in groundwater development and support the plans of future uses (exploitation) and groundwater management. A hydrogeological model was prepared to examine qualitative evaluation of aquifers media related to geochemical processes. Spatial hydrochemical bi-models were achieved for quantitative interpretation. Various graphical plots such as Piper, Durov, and Gibbs diagrams are used in proving different geochemical processes. The results are correlated with standards classifications to deduce the hydrogeo-chemical phenomena. The results showed that the groundwater of Um Erdhuma-Tayarat aquifer has a property of Carbonate weathering represents the major hydrogeochemical processes. In addition, ion exchange and reverse ion exchange were two possible processes of water-rock interaction (e.g. dolomitization processes) within the hydrogeologic system. Also, the evaporation process and mixing action of recharge vadose waters, and ancient trapped fossil waters have a moderate effect on the evolution of groundwater quality. An increased salt content is observed in groundwater at different static water levels indicating mixing with various sources. The mechanism controlling groundwater chemistry is originally related to geogenic process. In addition, anthropogenic activities have not significantly altered the geochemical nature of groundwater in the aquifers system.展开更多
The problem of repeated immersion-induced fatigue damage in engineering coal measures sedimentary rock,including coal-rock pillars,reservoir bank slopes,and water-rich tunnels at the boundary of coal mine underground ...The problem of repeated immersion-induced fatigue damage in engineering coal measures sedimentary rock,including coal-rock pillars,reservoir bank slopes,and water-rich tunnels at the boundary of coal mine underground reservoirs,has profound implications for their stability,safety,and operation,and can even lead to geological disasters.To address this issue,this paper aims to construct a constitutive model that accurately captures the comprehensive process of deformation and failure in water-bearing coal measures sedimentary rock.It explores the deformation characteristics of these formations and provides a theoretical foundation for numerical simulations of geological disasters induced by water-rock interaction.This study integrates the deformation mechanisms of void and matrix deformation in coal seam sedimentary rocks,while considering the influence of immersion cycles.Subsequently,it formulates a segmented constitutive model to depict the entire process of deformation and failure in cyclically immersed water-bearing coal measures sedimentary rock under uniaxial compression.The proposed model's accuracy and rationality are validated through comparisons with experimental research findings and existing theoretical curves from similar models.The results demonstrate the model's effectiveness in describing the deformation behavior of non-dense water-bearing coal measures sedimentary rock under uniaxial compression or low confining pressure before reaching peak stress,although further refinements may be necessary to precisely capture post-peak deformation characteristics.Model parameters,including the deformation caused by voids(γ0)between voids,increase exponentially with immersion times,while the elastic modulus(Ev)of voids and the parameter(F0)related to the average strength of microelements decrease exponentially.The homogeneity degree(m)exhibits no discernible pattern.These research outcomes provide valuable insights for the stability control of engineering coal measures sedimentary rock under water-rock interaction and the mitigation of related geological disasters.展开更多
The evolution of hydrochemical compositions influenced by long-period interactions between groundwater and the geo-environment is a fundamental issue for exploring groundwater quality and vulnerability.This study syst...The evolution of hydrochemical compositions influenced by long-period interactions between groundwater and the geo-environment is a fundamental issue for exploring groundwater quality and vulnerability.This study systematically investigated the hydrochemical processes and anthropogenic interference occurring in the river basin by bivariate plots,Gibbs diagrams,saturation index,and the major ions ratios.Apparent changes in groundwater hydrochemistry have been observed in the study area,illustrating the origins of major ions are affected by various internal and external factors.Results highlighted that TDS varied from freshwater to brackish water,ranging between 187.90 and 2294.81 mg/L.Ca^(2+)and HCO_(3)^(−)are the dominant ions in the studied samples.The results gained by Gibbs diagrams,bivariate plots,saturation index,and the major ions ratios demonstrated that minerals dissolution/precipitation,cation exchange,and human inputs play crucial roles in the unconfined aquifers.Moreover,the overuse of nitrogen fertilizer,livestock manure,and industrial/domestic sewage led to nitrate and nitrite contamination and brought significant challenges to the surrounding hydrogeo-environment.The present study could make an unambiguous identification of natural processes and anthropogenic interventions influencing groundwater hydrochemistry’s long-period evolution and create a preliminary strategy for groundwater resources management.展开更多
基金supported by the Central Public Welfare Scientific Research Basic Scientific Research Business Expenses(Grant Nos.KK2005,KY1603)National Natural Science Foundation of China(Grant No.U20A2092)+1 种基金the National Basic Research Program of China(973 Program)(Grant No.2011CB403007)the China Geological Survey(Grant No.DD20190606)。
文摘Deep-seated potassium-rich brines were identified in the Jiangling Basin,South China.Although magmatichydrothermal sources have been proposed,the relationship between brine-type potash mineralization and volcanism remains unclear.In this study,U-Pb geochronology,geochemistry,fluid inclusion and C-O isotopic compositions of hydrothermal vein minerals in the Jiangling Basin are examined.Laser ablation U-Pb dating of calcite veins indicates that the ages are slightly younger than the formation age of the Balingshan basalt.Fluid inclusions in hydrothermal minerals show medium–low homogenization temperatures(160–220℃)and low salinities(0.14 to 4.9 wt%NaCl eqv.)and densities(0.882–0.944 g/cm^(3)).The liquid compositions of fluid inclusions in calcite veins from sedimentary strata have higher contents of potassium,compared with those from basalt.The coupled negativeδ^(13)CPDB(-10.3‰to-8.0‰)and positiveδ^(18)OSMOW(17.4‰to 20.7‰)values imply that calcite precipitation resulted from CO_(2)degassing of the basaltic magmatic fluids,as indicated by the gas composition of these inclusions in hydrothermal minerals.Rare earth element patterns indicate that water-rock interaction between hydrothermal fluids and sedimentary wall rocks contributed to the calcite precipitation in sedimentary strata.It is proposed that high-temperature water-rock interaction between magmatic fluids and sedimentary strata resulted in the potassium enrichment in fluids,interpreted as one of the sources of potassium-rich brines in the Jiangling Basin.
基金This work was co-supported by the Yue Qi Young Scholar Project,China University of Mining&Technology,Beijing(2019QN08)National Key Research and Development Program of China(2018YFC0406404)+2 种基金Research on Ecological Restoration and Protection of Coal Base in Arid Eco-fragile Region(GJNY2030XDXM-19-03.2)the Fundamental Research Funds for the Central Universities(2020YJSHH12)the scientific and technological innovation project of Shenhua Group(SHJT-16-28).
文摘This paper presents results of an experimental study to characterize the law of mineral change of fallen rock in coal mine groundwater reservoir ant its influence on water quality.The minerals of the underground reservoir of Daliuta Coal Mine is taken as the research object.Simulation experiments were designed and conducted to simulate water–rock action in the laboratory.The mineral composition was analyzed by X-ray diffractometer(XRD),the surface morphology of the mineral was analyzed by scanning electron microscope(SEM),and the specific surface area,total pore volume and average pore diameter of the mineral were measured by fast specific surface/pore analyzer(BET).The experimental results show that the sandstone and mudstone in the groundwater reservoir of Daliuta Coal Mine account for 70%and 30%,respectively.The pore diameter is 15.62–17.55 nm,and pore volume is 0.035 cc/g.Its pore structure is a key factor in the occurrence of water–rock interaction.According to the water–rock simulation experiment,the quartz content before the water–rock action is about 34.28%,the albite is about 21.84%,the feldspar is about 17.48%,and the kaolinite is about 8.00%.After the water–rock action,they are 36.14%,17.78%,11.62%,and 16.75%,respectively.The content of albite and orthoclase is reduced while the content of kaolinite is increased,that is,the Na+content becomes higher,and the Ca2+and Mg2+contents become lower.This research builds a good theoretical foundation for revealing the role of water and rock in underground coal reservoirs.
基金the Postgraduate Innovation Fund project of Anhui University of Science and Technology(2019CX2006)the National Natural Science Foundation of China(41773100)+1 种基金a Research Project of Huaibei Mining Group Co.(2020)a Research Project of Wanbei Coal-Electricity Group Co.,Ltd.(2020).
文摘The aim of this study is to evaluate the hydrogeochemical characteristics and water environmental quality of shallow groundwater in the Suxian mining area of Huaibei coalfield,China.The natural formation process of shallow groundwater in Suxian is explored using Piper trilinear charts and Gibbs diagrams,and by examining the ratios between the major ions.United States Salinity Laboratory(USSL)charts,Wilcox diagrams,and the water quality index(WQI)are further employed to quantify the differences in water quality.The results reveal that the main hydrochemical facies of groundwater are HC03-Ca,and that silicate dissolution is the main factor controlling the ion content in shallow groundwater.The USSL charts and Wilcox diagrams show that most of the water samples would be acceptable for use in irrigation systems.The WQI results for each water sample are compared and analyzed,and the quality of groundwater samples around collapse ponds is found to be relatively poor.
基金This paper was supported by project of Customized Agricultural Geological Survey and Evaluation of Yam-Growing Regions in Heze Area of Dingtao County in Shangdong Province from 2016 Heze Ministry of Natural Resource’s financial project at the municipal level.
文摘Based on the analysis of element correlation,the Gibbs diagram,hydro-geochemical ion ratios,isoline maps of groundwater and soil,and change patterns of strontium content after normalization,the study examines water-rock interaction of shallow groundwater in Dingtao area.The results suggest that strontium in the study area mainly comes from waterrock interactions,and the strata interacting with groundwater are the top of Quaternary and Neogene.The element correlation analysis shows that the formation of strontium-rich groundwater is sufficiently affected by sulfate and carbonate.The Gibbs diagram suggests that the chemical composition of groundwater is mainly influenced by water-rock interactions,accompanied by evaporation crystallization.c(Ca2++Mg2+)/c(HCO3-+SO42-)reflects that the main reactions in the groundwater system is weathering dissolution of carbonate and sulfate,and ion exchange takes place.c(Na+)/c(Cl-)indicates that Na+in groundwater may have waterrock interactions with rocks it flows through.c(Cl-)/c(Ca2+)indicates that the hydrodynamic condition in the pumping well is poor and the water circulation is slow.The study examines the macro isoline map change patterns,correlation curves of change of strontium content in groundwater and shallow soil,and correlation curves of change of strontium content in groundwater,shallow soil,and deep soil.The results suggest that the strontium content in the study area has the same change pattern in groundwater and in soil,which further indicates that strontium in the study area comes from water-rock interactions.
文摘This study focuses on the geochemical and bacteriological investigation of surface and ground water in the Bamoun plateau (Western-Cameroon). During the period from September 2013 to August 2014, 71 samples were collected from two springs, one borehole, four wells and the Nchi stream for analysis of major elements. In order to obtain the characteristics of the various species of bacteria, 7 samples were selected. The analytical method adopted for this study is the conventional hydrochemical technic and multivariate statistical analysis, coupled with the hydrogeochemical modelling. The results revealed that, water from the zone under study are acidic to basic, very weakly to weakly mineralized. Four types of water were identified: 1) CaMg-HCO<sub>3</sub>;2) CaMg-Cl-SO<sub>4</sub>;3) NaCl-SO<sub>4</sub> and 4) NaK-HCO<sub>3</sub>. The major elements were all listed in the World Health Organization guidelines for drinking water quality, except for nitrates which was found at a concentration > 50 mg /l <span style="white-space:nowrap;">NO<sup>-</sup><sub style="margin-left:-7px;">3</sub> </span>in the borehole F401. As for the hydrobiological aspect, the entire sample contained all the bacteriological species except for spring S301 and well P401. According to the hydrogeochemical modelling, the Gibbs model and multivariate statistical tests, the quality of surface and ground water of the Foumban locality is influenced by two important factors: 1) the natural factors characterized by the water-rock interaction, evapotranspiration/crystallization, 2) the anthropogenic factors such as: uncontrolled discharges of liquid and solid effluents of all kinds and without any prior treatment within the ground and the strong urbanization accompanied by lack of sanitation and insufficient care.
基金Acknowledgements The authors are grateful for the fnancial support from the key scientifc research project of Shanxi Province(No.57820191101016)the bidding project of Shanxi Province of China(No.20191101016)the Doctoral Innovation Fund of Anhui University of Science and Technology(No.2021CX1003).
文摘The instability of underground spaces in abandoned coal mines with water-immersed rocks is one of the main hazards hindering the geothermal energy use and ecological restoration of post-mining areas.This study conducted graded cyclic loading–unloading tests of fve groups of sandstone samples with diferent water contents.The evolution of input,elastic,dissipated,damping,and plastic energies were explored,considering the damping efect.The normalized plastic energy serves to characterize the damage evolution of sandstone samples,whose failure characteristics were analyzed from both the macroscopic and microscopic perspectives.X-ray difraction technique and scanning electron microscopy were used to reveal the softening mechanism of sandstone.The results show that under graded cyclic loading,input energy,elastic energy,and dissipated energy all increase gradually,and the fraction of elastic energy increases gradually at frst and then tends to stabilize.The variation in the fraction of dissipated energy is opposite to that of elastic energy.In each cycle,the input energy is stored primarily in the form of elastic energy,whereas the dissipated energy is used primarily to overcome the damping of sandstone.When the normalized number of cycles approached unity,the plastic energy fraction sharply increases,while that of the dampening energy drops abruptly.With increasing water content,the efect of pore water on the lubrication,the water wedge,and dissolution of mineral particles becomes more obvious,reducing the elastic-storage limit of sandstone,meanwhile the sandstone damage factor increases signifcantly under the same cycle and the failure mode changes from brittle to ductile.
文摘Umm Er Radhuma Aquifer (UER) is the most important groundwater aquifer in Saudi Arabia, extending over 1.6 M<span style="font-size:10.5pt;font-family:;" "=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span></span></span>km<sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> in the eastern part of the Arabian Peninsula, forming the main aquifer throughout the Rub’ Al-Khali (RAK). </span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">Groundwater salinity increased from west to east, reaching more than 27,000 mg/L near the border with the United Arab Emirates, where a Na</span><sup><span style="font-family:Verdana;">+</span></sup><span style="font-family:Verdana;">-Ca</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;">Cl<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span><span style="font-family:Verdana;">-<img src="Edit_c1bbc858-a8a7-45ca-be57-e2bb456cbddb.bmp" alt="" /></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> </span></span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">water type dominated. Gibbs diagrams indicated that the dissolution/precipitation of carbonates and evaporation/precipitation of minerals, especially anhydrite, gypsum, and halite account for the solutes and salinity in groundwater. Most of the samples plot above the 1:1 line of (Ca</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;"> + Mg</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;">) against <img src="Edit_5405b197-c8d5-436d-8648-dd95afefb8e6.bmp" alt="" /></span></span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">, indicating other sources of Ca</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;"> and Mg</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;"> in the groundwater along with dolomite and calcium carbonate minerals. Phreeqc model indicated that the main clay minerals are kaolinite and gibbsite which had major effect on the cation exchange process as indicated by the Chloro-Alkaline index (CAI), where most of groundwater samples had values greater than zero which indicated the occurrence of reverse ion exchange between the groundwater and its host aquifer. The water type Na</span><sup><span style="font-family:Verdana;">+</span></sup><span style="font-family:Verdana;">-Ca</span><sup><span style="font-family:Verdana;">2+</span></sup><span style="font-family:Verdana;">Cl</span><sup><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">ˉ</span></span></sup><span style="font-family:Verdana;">-<img src="Edit_e8c17a28-24a8-4e14-a615-24c0e0817331.bmp" alt="" /></span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">dominated in the eastern part of the aquifer as the anaerobic conditions prevailed and the reduction of sulphate took place.</span></span></span></span>
基金Fundamental Research Funds for the Universities,Grant/Award Numbers:2020ZDPY0201,2022QN1061National Key Research and Development Project of China,Grant/Award Number:2019YFC1805400+1 种基金National Science Foundation of Jiangsu Province,Grant/Award Number:BK20210524National Natural Science Foundation,Grant/Award Number:42202268。
文摘For the sake of mine water drainage and sustainable groundwater protection,the new approach of mine water deep geological storage(MWDGS)is highly necessary to save water resources in the semi-arid region of China.However,up to now,little academic research has been done on mine water geological storage.Given this situation,the hydrogeological feasibility of MWDGS was explored in Baotashan coarse sandstone(BCS)of Jurassic measure in Ordos Basin.The results show that the white-gray BCS with a fragile skeleton of quartz(41.4%),feldspar(21.1%),and clay minerals(16.4%)provides the potential variable-void for mine water;and its hydro-chemical type of BCS aquifer is CO_(3)-Na and Cl-Na.As the burial depth increases,the strong alkaline groundwater is in stagnant and poor recharge-runoff-discharge condition.The lab test shows that the pores whose diameter is over 10μm could be treated as the main storage of mine water;and the effective porosity varies from 1.36%to 3.46%.When mine water is injected,the strong hydrodynamics of mine water storage would change the permeability significantly and about 0.201%soluble solids would be dissolved.Partial clay minerals obstruct the pores and induce the saturated phase of high permeability to evolve into steady phase of lower permeability.Under the condition of nonhydraulic fracturing during continuous storage,the heterogeneous anisotropic medium obtained by Transition PRObability GeoStatistics(TPROGS)shows that the capacity of BCS aquifer is 0.455 to 1.226Mm^(3)for 1 km^(2)in the study area.The simulation shows that the groundwater mound in well-scale and mine-scale would be formed.The groundwater quality characteristics of“Three Zone”would occur around and gradually drop to approximate the original brine within 10 years.The hydrogeological feasibility reveals that this approach is useful for the well design and groundwater environment management during the mine water deep geological storage project in the Ordos basin.
文摘Hydrogeological investigation of groundwater has been performed within Kasra- Nukhaib district (west Iraq). The physicochemical analyses of the groundwater samples collected from Um Erdhuma-Tayarat aquifer are used in determination of hydrogeochemical processes, hydrochemical facies, hydrochemical ratio, and saturation indices supported by phreeqc software. The monitoring network of groundwater quality consists of twelve physiochemical variables in twenty four water wells were determined, aiming to examine the hydrogeo-chemical phenomena which are benefit in groundwater development and support the plans of future uses (exploitation) and groundwater management. A hydrogeological model was prepared to examine qualitative evaluation of aquifers media related to geochemical processes. Spatial hydrochemical bi-models were achieved for quantitative interpretation. Various graphical plots such as Piper, Durov, and Gibbs diagrams are used in proving different geochemical processes. The results are correlated with standards classifications to deduce the hydrogeo-chemical phenomena. The results showed that the groundwater of Um Erdhuma-Tayarat aquifer has a property of Carbonate weathering represents the major hydrogeochemical processes. In addition, ion exchange and reverse ion exchange were two possible processes of water-rock interaction (e.g. dolomitization processes) within the hydrogeologic system. Also, the evaporation process and mixing action of recharge vadose waters, and ancient trapped fossil waters have a moderate effect on the evolution of groundwater quality. An increased salt content is observed in groundwater at different static water levels indicating mixing with various sources. The mechanism controlling groundwater chemistry is originally related to geogenic process. In addition, anthropogenic activities have not significantly altered the geochemical nature of groundwater in the aquifers system.
基金financially supported by National Natural Science Foundation of China(51874283)Youth Fund of the National Natural Science Foundation of China(52304133)Department of Science and Technology of Liaoning province(2023-BS-083).
文摘The problem of repeated immersion-induced fatigue damage in engineering coal measures sedimentary rock,including coal-rock pillars,reservoir bank slopes,and water-rich tunnels at the boundary of coal mine underground reservoirs,has profound implications for their stability,safety,and operation,and can even lead to geological disasters.To address this issue,this paper aims to construct a constitutive model that accurately captures the comprehensive process of deformation and failure in water-bearing coal measures sedimentary rock.It explores the deformation characteristics of these formations and provides a theoretical foundation for numerical simulations of geological disasters induced by water-rock interaction.This study integrates the deformation mechanisms of void and matrix deformation in coal seam sedimentary rocks,while considering the influence of immersion cycles.Subsequently,it formulates a segmented constitutive model to depict the entire process of deformation and failure in cyclically immersed water-bearing coal measures sedimentary rock under uniaxial compression.The proposed model's accuracy and rationality are validated through comparisons with experimental research findings and existing theoretical curves from similar models.The results demonstrate the model's effectiveness in describing the deformation behavior of non-dense water-bearing coal measures sedimentary rock under uniaxial compression or low confining pressure before reaching peak stress,although further refinements may be necessary to precisely capture post-peak deformation characteristics.Model parameters,including the deformation caused by voids(γ0)between voids,increase exponentially with immersion times,while the elastic modulus(Ev)of voids and the parameter(F0)related to the average strength of microelements decrease exponentially.The homogeneity degree(m)exhibits no discernible pattern.These research outcomes provide valuable insights for the stability control of engineering coal measures sedimentary rock under water-rock interaction and the mitigation of related geological disasters.
基金the National Natural Science Foundation of Chinaunder Grant Nos.41571214 and 41807010。
文摘The evolution of hydrochemical compositions influenced by long-period interactions between groundwater and the geo-environment is a fundamental issue for exploring groundwater quality and vulnerability.This study systematically investigated the hydrochemical processes and anthropogenic interference occurring in the river basin by bivariate plots,Gibbs diagrams,saturation index,and the major ions ratios.Apparent changes in groundwater hydrochemistry have been observed in the study area,illustrating the origins of major ions are affected by various internal and external factors.Results highlighted that TDS varied from freshwater to brackish water,ranging between 187.90 and 2294.81 mg/L.Ca^(2+)and HCO_(3)^(−)are the dominant ions in the studied samples.The results gained by Gibbs diagrams,bivariate plots,saturation index,and the major ions ratios demonstrated that minerals dissolution/precipitation,cation exchange,and human inputs play crucial roles in the unconfined aquifers.Moreover,the overuse of nitrogen fertilizer,livestock manure,and industrial/domestic sewage led to nitrate and nitrite contamination and brought significant challenges to the surrounding hydrogeo-environment.The present study could make an unambiguous identification of natural processes and anthropogenic interventions influencing groundwater hydrochemistry’s long-period evolution and create a preliminary strategy for groundwater resources management.
