The purpose of this paper is to examine the evolution mechanisms of a hydrochemical field and to promote its benefits to the living standards of local people and to the local economy in the southern plain area of Peng...The purpose of this paper is to examine the evolution mechanisms of a hydrochemical field and to promote its benefits to the living standards of local people and to the local economy in the southern plain area of Pengyang County, in Ningxia, China. Based on understanding of the hydrogeological conditions in Pengyang County, the chemical evolution characteristics of groundwater in the plain area were analyzed. PHREEQC geochemical modeling software was used to perform hydrochemical modeling of water-rock interaction and to quantitatively analyze the evolution processes and the formation mechanisms of the local groundwater. Geochemical modeling was performed for two groundwater paths. The results showed that, along path 1, Na+ adsorption played the leading role in the precipitation process and its amount was the largest, up to 6.08 mmol/L; cation exchange was significant along path 1, while along simulated path 2, albite accounted for the largest amount of dissolution, reaching 9.06 mmol/L, and the cation exchange was not significant. According to the modeling results, along the groundwater flow path, calcite and dolomite showed oversaturated status with a precipitation trend, while the fluorite and gypsum throughout the simulated path were not saturated and showed a dissolution trend. The total dissolved solids (TDS) increased and water quality worsened along the flow path. The dissolution reactions of albite, CO2, and halite, the exchange adsorption reaction of Na+, and the precipitation of sodium montmorillonite and calcite were the primary hydrogeochemical reactions, resulting in changes of hydrochemical ingredients.展开更多
The Changkeng gold-silver deposits consist of a sediment-hosted, disseminated gold deposit and a replacement-type silver deposit. The mineralizations of gold and silver are zoned and closely related to the silicificat...The Changkeng gold-silver deposits consist of a sediment-hosted, disseminated gold deposit and a replacement-type silver deposit. The mineralizations of gold and silver are zoned and closely related to the silicification of carbonate and clastic rocks, so that siliceous ores dominate in the deposit. The mineralizing temperature ranges mainly from 300 to 170℃, and K+, Na+, Ca2+, Mg2+, and Cl- are the major ions in the ore-forming fluid. Calculations of distribution of metal complexes show that gold is mainly transported by hydrosulphide complexes, but chloride complexes of silver, iron, lead, and zinc, which are transformed into hydroxyl and hydrosulphide complexes under neutral to weak-alkaline circumstances in the late stage, predominate in the ore-forming solutions. Water-rock interaction is confirmed to be the effective mechanism for the formation of silver ores by computer modelling of reaction of hydrothermal solution with carbonate rocks. The solubility analyses demonstrate that the precipitation of gold and silver-bearing minerals taking place under weak-acid conditions and near-neutral to weak-alkaline conditions, respectively, is the main or favourable factor for the ore zonation and separation between gold and silver.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
Using the hydrogeochemical modeling method, the groundwater chemical environmental problems of the Hebei Plain which involve increasing of hardness and total dissolved solids in piedmont area and mixing of saline wate...Using the hydrogeochemical modeling method, the groundwater chemical environmental problems of the Hebei Plain which involve increasing of hardness and total dissolved solids in piedmont area and mixing of saline water with fresh water in middle-eastern area are studied. The water-rock interactions and mass transfer along a ground-water flow path and in mixing processes are calculated. Thus the evolution mechanisms of the groundwater chemical environment are brought to light.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.40772160)the Research on Drinking Water Environment and Endemic in Villages and Small Towns in New Socialist Countryside Project (Grant No.010)supported by the Ningxia Land and Resources Department,and the Program of Introducing Talents of Discipline to Universities (111 Project) (Grant No.B08039)
文摘The purpose of this paper is to examine the evolution mechanisms of a hydrochemical field and to promote its benefits to the living standards of local people and to the local economy in the southern plain area of Pengyang County, in Ningxia, China. Based on understanding of the hydrogeological conditions in Pengyang County, the chemical evolution characteristics of groundwater in the plain area were analyzed. PHREEQC geochemical modeling software was used to perform hydrochemical modeling of water-rock interaction and to quantitatively analyze the evolution processes and the formation mechanisms of the local groundwater. Geochemical modeling was performed for two groundwater paths. The results showed that, along path 1, Na+ adsorption played the leading role in the precipitation process and its amount was the largest, up to 6.08 mmol/L; cation exchange was significant along path 1, while along simulated path 2, albite accounted for the largest amount of dissolution, reaching 9.06 mmol/L, and the cation exchange was not significant. According to the modeling results, along the groundwater flow path, calcite and dolomite showed oversaturated status with a precipitation trend, while the fluorite and gypsum throughout the simulated path were not saturated and showed a dissolution trend. The total dissolved solids (TDS) increased and water quality worsened along the flow path. The dissolution reactions of albite, CO2, and halite, the exchange adsorption reaction of Na+, and the precipitation of sodium montmorillonite and calcite were the primary hydrogeochemical reactions, resulting in changes of hydrochemical ingredients.
基金This project was financially supported by Research Funds of Gold Resources and Doctoral Training Funds sponsored by Chinese Academy of Sciences
文摘The Changkeng gold-silver deposits consist of a sediment-hosted, disseminated gold deposit and a replacement-type silver deposit. The mineralizations of gold and silver are zoned and closely related to the silicification of carbonate and clastic rocks, so that siliceous ores dominate in the deposit. The mineralizing temperature ranges mainly from 300 to 170℃, and K+, Na+, Ca2+, Mg2+, and Cl- are the major ions in the ore-forming fluid. Calculations of distribution of metal complexes show that gold is mainly transported by hydrosulphide complexes, but chloride complexes of silver, iron, lead, and zinc, which are transformed into hydroxyl and hydrosulphide complexes under neutral to weak-alkaline circumstances in the late stage, predominate in the ore-forming solutions. Water-rock interaction is confirmed to be the effective mechanism for the formation of silver ores by computer modelling of reaction of hydrothermal solution with carbonate rocks. The solubility analyses demonstrate that the precipitation of gold and silver-bearing minerals taking place under weak-acid conditions and near-neutral to weak-alkaline conditions, respectively, is the main or favourable factor for the ore zonation and separation between gold and silver.
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Project supported by the National Natural Science Foundation of China
文摘Using the hydrogeochemical modeling method, the groundwater chemical environmental problems of the Hebei Plain which involve increasing of hardness and total dissolved solids in piedmont area and mixing of saline water with fresh water in middle-eastern area are studied. The water-rock interactions and mass transfer along a ground-water flow path and in mixing processes are calculated. Thus the evolution mechanisms of the groundwater chemical environment are brought to light.