2002 Vol. 27, No. 2
Display Method:
2002, 27(2): 127-133.
PDF 305KB
Abstract:
The history of water rock interaction studies since the 1950s' is divided into three periods: the first (late 1950s' - early 1970s'), the second (early 1970s' - late 1980s') and the third (late 1980s' - present). In recent years, environmental problems become increasingly important for water rock interaction studies and provide more opportunities for the greater and sustainable development of water rock interaction studies. Some important advances in the following aspects are briefly reviewed in this paper: the genesis of groundwaters and the geochemical cycle of water in the earth's crust; geochemical processes controlling the chemical compositions of water, and water rock interaction and geohazards. Perspectives concerning the following research fields where innovative results may occur are discussed: the geological role of groundwaters and the resource environmental effects; groundwater environment evolution and global change; water rock interaction studies under extreme conditions.
The history of water rock interaction studies since the 1950s' is divided into three periods: the first (late 1950s' - early 1970s'), the second (early 1970s' - late 1980s') and the third (late 1980s' - present). In recent years, environmental problems become increasingly important for water rock interaction studies and provide more opportunities for the greater and sustainable development of water rock interaction studies. Some important advances in the following aspects are briefly reviewed in this paper: the genesis of groundwaters and the geochemical cycle of water in the earth's crust; geochemical processes controlling the chemical compositions of water, and water rock interaction and geohazards. Perspectives concerning the following research fields where innovative results may occur are discussed: the geological role of groundwaters and the resource environmental effects; groundwater environment evolution and global change; water rock interaction studies under extreme conditions.
2002, 27(2): 135-140.
Abstract:
This paper points out the possible problems in using line sink to describe a horizontal wellbore. It presents a new model to describe a horizontal well with consideration of different flow regions and the laminar and turbulent flow, i.e. linear and nonlinear flow inside the pumping well. Hence, it sets up the inner boundary at a point where water flows out. As it does not need flux or head distribution along the horizontal well, it may avoid the difficulty in using the line sink assumption. This paper uses an "equivalent hydraulic conductivity" concept and its determined approach to treat the horizontal wellbore, which treats the aquifer horizontal well system as a heterogeneous medium with a cylinder lens. It also provides a mathematical model and numerical simulation to solve the flow problem. A sample of a horizontal well pumpage underneath a river is calculated to illustrate the presented model and numerical method and the simulation results of groundwater behavior are indicated.
This paper points out the possible problems in using line sink to describe a horizontal wellbore. It presents a new model to describe a horizontal well with consideration of different flow regions and the laminar and turbulent flow, i.e. linear and nonlinear flow inside the pumping well. Hence, it sets up the inner boundary at a point where water flows out. As it does not need flux or head distribution along the horizontal well, it may avoid the difficulty in using the line sink assumption. This paper uses an "equivalent hydraulic conductivity" concept and its determined approach to treat the horizontal wellbore, which treats the aquifer horizontal well system as a heterogeneous medium with a cylinder lens. It also provides a mathematical model and numerical simulation to solve the flow problem. A sample of a horizontal well pumpage underneath a river is calculated to illustrate the presented model and numerical method and the simulation results of groundwater behavior are indicated.
2002, 27(2): 140-140.
Abstract:
2002, 27(2): 141-147.
Abstract:
The paper put forward a concept of regional groundwater resources attribute from point of sustainability based on isotope information. It analyzed the distribution of groundwater age in the aquifer system, groundwater resources attribute in some regional aquifer systems using isotope data and the effect of human activities (groundwater exploitation) on regional groundwater resources attribute. It point out that the direct and cost effective tool for assessment of regional groundwater resources attribute is environmental isotopes, and correct recognition and estimation of regional groundwater resources attribute will play a very important role on realizing groundwater resources sustainability.
The paper put forward a concept of regional groundwater resources attribute from point of sustainability based on isotope information. It analyzed the distribution of groundwater age in the aquifer system, groundwater resources attribute in some regional aquifer systems using isotope data and the effect of human activities (groundwater exploitation) on regional groundwater resources attribute. It point out that the direct and cost effective tool for assessment of regional groundwater resources attribute is environmental isotopes, and correct recognition and estimation of regional groundwater resources attribute will play a very important role on realizing groundwater resources sustainability.
2002, 27(2): 148-152.
Abstract:
Agroecological geology groups and types are a comprehensive result from agroecological geology investigations, and are the basic units for the investigation and mapping. With a view on geological environment and agroecology system, the authors put forward three principles for distinguishing agroecological geology groups and types, which are dominant rules in the system, quality differences in agro ecology, and macro characteristics in favor of field investigations. There are 3 groups and 16 types, presenting remarkable quality differences in agro ecology in the research area.
Agroecological geology groups and types are a comprehensive result from agroecological geology investigations, and are the basic units for the investigation and mapping. With a view on geological environment and agroecology system, the authors put forward three principles for distinguishing agroecological geology groups and types, which are dominant rules in the system, quality differences in agro ecology, and macro characteristics in favor of field investigations. There are 3 groups and 16 types, presenting remarkable quality differences in agro ecology in the research area.
2002, 27(2): 153-156.
Abstract:
Partial CO2pressure(p(CO2))of groundwater from Qijia water supply base and mass transfers after the groundwater being pumped out to equilibrate with atmospheric CO2are calculated by hydrogeochemical modeling. The results show that the groundwater p(CO2)is pronounced higher than atmospheric p(CO2), and that 11.15 mmol/kg CO2will be emitted to the atmosphere when the groundwater reaches the surface. Further discussion has revealed that different lithologic aquifers usually contain higher groundwater p(CO2).Consequently, groundwater exploitation hasbecome a man-made CO2source and should arouse our attention.
Partial CO2pressure(p(CO2))of groundwater from Qijia water supply base and mass transfers after the groundwater being pumped out to equilibrate with atmospheric CO2are calculated by hydrogeochemical modeling. The results show that the groundwater p(CO2)is pronounced higher than atmospheric p(CO2), and that 11.15 mmol/kg CO2will be emitted to the atmosphere when the groundwater reaches the surface. Further discussion has revealed that different lithologic aquifers usually contain higher groundwater p(CO2).Consequently, groundwater exploitation hasbecome a man-made CO2source and should arouse our attention.
2002, 27(2): 157-162.
Abstract:
The deep-lying alkaline fresh groundwater in sedimentary system in Hebei plain is taken as a research object for the purpose of revealing its chemical formation mechanism. Taking Baoding and Cangzhou districts where the deep-lying alkaline fresh groundwater is widely distributed as a typical study area and using the hydrogeochemical synthetic analysis and modeling methods, the authors discussed the chemical property, distribution and formation environment of deep-lying alkaline fresh groundwater. According to the principle of mass conservation, they set up a mass balance reaction model and studied hydrogeochemical reactions and mass transfer between water and rock along the flow path from piedmont to coastal area so as to have brought to light the chemical evolution law of deep-lying groundwater and the formation mechanism of alkaline fresh water. Their main conclusion is that the deep-lying alkaline fresh groundwater is originated from the evolution of the HCO3-Ca·Mg water in piedmont area, and that from the piedmont the middle plain, the dissolution and precipitation of calcite and dolomite, the dissolution of albite, gypsum, halite and siderite, and the cation exchange of Ca-Na during the processes of groundwater environment changing from "open" to "closed" are the dominant hydrogeochemical reactions leading to its formation and evolution.
The deep-lying alkaline fresh groundwater in sedimentary system in Hebei plain is taken as a research object for the purpose of revealing its chemical formation mechanism. Taking Baoding and Cangzhou districts where the deep-lying alkaline fresh groundwater is widely distributed as a typical study area and using the hydrogeochemical synthetic analysis and modeling methods, the authors discussed the chemical property, distribution and formation environment of deep-lying alkaline fresh groundwater. According to the principle of mass conservation, they set up a mass balance reaction model and studied hydrogeochemical reactions and mass transfer between water and rock along the flow path from piedmont to coastal area so as to have brought to light the chemical evolution law of deep-lying groundwater and the formation mechanism of alkaline fresh water. Their main conclusion is that the deep-lying alkaline fresh groundwater is originated from the evolution of the HCO3-Ca·Mg water in piedmont area, and that from the piedmont the middle plain, the dissolution and precipitation of calcite and dolomite, the dissolution of albite, gypsum, halite and siderite, and the cation exchange of Ca-Na during the processes of groundwater environment changing from "open" to "closed" are the dominant hydrogeochemical reactions leading to its formation and evolution.
2002, 27(2): 163-167.
Abstract:
Geothermal waterin the basement aquifers near Tianjin is characterized by a significant change in density of the water with its temperature and an exchange of heat between the water and its surrounding rocks. This paper puts forward the governing equations of pressure and temperature for describing water flow and heat transport of the deep-seated geothermal system. The 3-dimensional numerical model established are proved more effective and practical by the reasonable generalization and treatment of the flow domain, boundary and initial conditions, missing areas of the aquifers, and tilted faults.
Geothermal waterin the basement aquifers near Tianjin is characterized by a significant change in density of the water with its temperature and an exchange of heat between the water and its surrounding rocks. This paper puts forward the governing equations of pressure and temperature for describing water flow and heat transport of the deep-seated geothermal system. The 3-dimensional numerical model established are proved more effective and practical by the reasonable generalization and treatment of the flow domain, boundary and initial conditions, missing areas of the aquifers, and tilted faults.
2002, 27(2): 168-172.
Abstract:
Aimed at the current difficult problem of fix quantitative forecast and math description about pore position in karstology, the water-bearing karst-fissure medium in Jinan spring area was selected as a typical research area because of its higherinvestigation degree, abundant data and typical representation. The connectivity among pore was studied and the position of karst-fissure concentration and strong runoff zones were forecasted by applying sequence-indicator conditional simulation. It shows that the method can give the fluctuation interval of simulated data, and at the same time, the obvious conformance of different quantile simulation map indicates the position of karst-fissure concentration and strong runoff zones, especially when sample size is small(the identical effect can be obtained as large sample size). Thereby, the method can be applied to a wider extent.
Aimed at the current difficult problem of fix quantitative forecast and math description about pore position in karstology, the water-bearing karst-fissure medium in Jinan spring area was selected as a typical research area because of its higherinvestigation degree, abundant data and typical representation. The connectivity among pore was studied and the position of karst-fissure concentration and strong runoff zones were forecasted by applying sequence-indicator conditional simulation. It shows that the method can give the fluctuation interval of simulated data, and at the same time, the obvious conformance of different quantile simulation map indicates the position of karst-fissure concentration and strong runoff zones, especially when sample size is small(the identical effect can be obtained as large sample size). Thereby, the method can be applied to a wider extent.
2002, 27(2): 173-176.
Abstract:
Five origins of 36Cl in calcite were studied theoretically: (1)near-surface production by Ca spallation and spallogenic neutron capture, (2)negative muon capture by calcium, (3)neutron emission following negative muon capture, (4)neutrons from photodisintegration reactions initiated by fast muons, (5) neutron from uranium fission and(α, n)reactions. Four characteristics of 36Cl distribution for deep profile in limestone have been discussed: (1)36Cl concentration is reduced with depth, (2)depth naturally separates 36Cl contributions from the various production reactions, (3)in order to partition measured 36Cl concentrations into contributions from muon capture on Ca and capture of muon-produced neutrons on 35Cl, the sample set must possess a range of Ca/Cl ratios, (4)limestone erosion is inevitable under even the most arid conditions and plays a significant role in determining steady-state concentrations.Sampling method of 36Cl and AMS analytical technique are described in detail.Mathematical model of determining erosion rate in limestone is studied and some surface erosion rate of limestone are evaluated.
Five origins of 36Cl in calcite were studied theoretically: (1)near-surface production by Ca spallation and spallogenic neutron capture, (2)negative muon capture by calcium, (3)neutron emission following negative muon capture, (4)neutrons from photodisintegration reactions initiated by fast muons, (5) neutron from uranium fission and(α, n)reactions. Four characteristics of 36Cl distribution for deep profile in limestone have been discussed: (1)36Cl concentration is reduced with depth, (2)depth naturally separates 36Cl contributions from the various production reactions, (3)in order to partition measured 36Cl concentrations into contributions from muon capture on Ca and capture of muon-produced neutrons on 35Cl, the sample set must possess a range of Ca/Cl ratios, (4)limestone erosion is inevitable under even the most arid conditions and plays a significant role in determining steady-state concentrations.Sampling method of 36Cl and AMS analytical technique are described in detail.Mathematical model of determining erosion rate in limestone is studied and some surface erosion rate of limestone are evaluated.
2002, 27(2): 177-180.
Abstract:
The approved genetic algorithm was combined with finite element method in developing relevant software. The software was applied to make back analysis of elastic module, cohesion, friction angle for the slope with different soil types. The results show that the error is quite small and convergence rate fast. It is proved this algorithm is of obvious priority in rock soil parameter estimation.
The approved genetic algorithm was combined with finite element method in developing relevant software. The software was applied to make back analysis of elastic module, cohesion, friction angle for the slope with different soil types. The results show that the error is quite small and convergence rate fast. It is proved this algorithm is of obvious priority in rock soil parameter estimation.
2002, 27(2): 181-185.
Abstract:
The components of the residual petrochemicals, variation of the microbe dehydrogenase activities and screening hydrocarbon degrading bacteria in the polluted soil of Zihe valley were measured by GC/MS, column chromatography, turbidity and microbe dehydrogenase methods. The experimental results indicate that petroleum carbons in the soil are composed of colloid and pitchy compounds accounting for 60%~80% of total petroleum carbons, which may limit the biodegradation of petrochemicals. It was proved that after 90 days the biodegradation rate of the petrochemicals was only 20%. The major types of the degrading bacteria in the polluted soil are cocci, or short and long bacilli based on the degradation experiments of naphthalene and liquid paraffin. Xanthomonas, Bacillus and a species thought to be Hyphomicrobium are identified to have high activity in the experiments. The pilot studies present that the microbe dehydrogenase can be used as index of the microbe activities for the biodegradation of petrochemicals.
The components of the residual petrochemicals, variation of the microbe dehydrogenase activities and screening hydrocarbon degrading bacteria in the polluted soil of Zihe valley were measured by GC/MS, column chromatography, turbidity and microbe dehydrogenase methods. The experimental results indicate that petroleum carbons in the soil are composed of colloid and pitchy compounds accounting for 60%~80% of total petroleum carbons, which may limit the biodegradation of petrochemicals. It was proved that after 90 days the biodegradation rate of the petrochemicals was only 20%. The major types of the degrading bacteria in the polluted soil are cocci, or short and long bacilli based on the degradation experiments of naphthalene and liquid paraffin. Xanthomonas, Bacillus and a species thought to be Hyphomicrobium are identified to have high activity in the experiments. The pilot studies present that the microbe dehydrogenase can be used as index of the microbe activities for the biodegradation of petrochemicals.
2002, 27(2): 186-188.
Abstract:
Carbon tetrachloride (CT) and tetrachloroethene (PCE) are the common contaminants in groundwater and drinking water because the chlorinated solvents are used in very large quantities and chlorine is used to disinfect drinking water. This paper describs the reductive dechlorination reaction using cheap iron scrapes. It discusses its kinetic process and factors that affect reaction rate. The results show that the zero valance iron is effective to the dechlorination of chlorinated hydrocarbon and that the reaction of CT is faster than that of PCE. Reaction is pseudo first order and the reaction rate is affected by specific surface area.
Carbon tetrachloride (CT) and tetrachloroethene (PCE) are the common contaminants in groundwater and drinking water because the chlorinated solvents are used in very large quantities and chlorine is used to disinfect drinking water. This paper describs the reductive dechlorination reaction using cheap iron scrapes. It discusses its kinetic process and factors that affect reaction rate. The results show that the zero valance iron is effective to the dechlorination of chlorinated hydrocarbon and that the reaction of CT is faster than that of PCE. Reaction is pseudo first order and the reaction rate is affected by specific surface area.
2002, 27(2): 189-192.
Abstract:
To against the disadvantages of lower increase of well discharge and serious pollution to groundwater in using the conventional methods of well acid treatment, the authors advanced a method of well acid treatment with periodic negative pressure. The stronger acid liquor in pit shaft are pushed into fissures of carbonatite aquifer and withdrawn the reaction products in the fissures by periodic negative pressure. Therefore the result using this method one time is equal to the conventional method and flushing for many times. Using periodic negative pressure and less amount of acid with multiple injection effectively reduces groundwater pollution. The practice results show that this method can increase 186% of average well discharge and reduce 59% of average drainage of polluted water in comparison with the conventional method. The method can be widely used because of its good results, lower pollution and cost, and convenient to be used.
To against the disadvantages of lower increase of well discharge and serious pollution to groundwater in using the conventional methods of well acid treatment, the authors advanced a method of well acid treatment with periodic negative pressure. The stronger acid liquor in pit shaft are pushed into fissures of carbonatite aquifer and withdrawn the reaction products in the fissures by periodic negative pressure. Therefore the result using this method one time is equal to the conventional method and flushing for many times. Using periodic negative pressure and less amount of acid with multiple injection effectively reduces groundwater pollution. The practice results show that this method can increase 186% of average well discharge and reduce 59% of average drainage of polluted water in comparison with the conventional method. The method can be widely used because of its good results, lower pollution and cost, and convenient to be used.
2002, 27(2): 193-198.
Abstract:
The controlled Lianziya hazardous rock, especially T8-T12 fracture segment will be affected over a long period of time when the Three Gorges reservoir stores water, which also relates to efficacy of the control project to the rock. Through mass field investigations and rock tests, this paper concerns with the long term effects of the reservoir to T8-T12 fracture segment and its deposits, and also recalculates the stability of the rock by using improved Sarma program. Then some new conclusions are obtained: generally, when the water level of Yangtze River rises, the water actions of erosion and tension will widen the fractures, and deteriorate the rock stability. On considering long term strengths of rock and control project, as well as rapid water rising and dropping, and also earthquake affection, the stability of hazardous rock will turn worse than before, whereas the condition in NE20° direction will be better than that in NW350°.
The controlled Lianziya hazardous rock, especially T8-T12 fracture segment will be affected over a long period of time when the Three Gorges reservoir stores water, which also relates to efficacy of the control project to the rock. Through mass field investigations and rock tests, this paper concerns with the long term effects of the reservoir to T8-T12 fracture segment and its deposits, and also recalculates the stability of the rock by using improved Sarma program. Then some new conclusions are obtained: generally, when the water level of Yangtze River rises, the water actions of erosion and tension will widen the fractures, and deteriorate the rock stability. On considering long term strengths of rock and control project, as well as rapid water rising and dropping, and also earthquake affection, the stability of hazardous rock will turn worse than before, whereas the condition in NE20° direction will be better than that in NW350°.
2002, 27(2): 199-202.
Abstract:
Theis model is the basic classic theory of pumping groundwater flow in confined aquifers, which neglects the bending effects of confining stratum on the aquifer water releasing. A new model is introduced in this paper with the theory of elastic plates to modify Theis model. The analysis of the new model is proved that drawdown evaluated by Theis model is low, which also was shown in the pumping test.
Theis model is the basic classic theory of pumping groundwater flow in confined aquifers, which neglects the bending effects of confining stratum on the aquifer water releasing. A new model is introduced in this paper with the theory of elastic plates to modify Theis model. The analysis of the new model is proved that drawdown evaluated by Theis model is low, which also was shown in the pumping test.
Discussion on Hydraulic Loading and Effluent Effect in Wastewater Infiltration land Treating Systems
2002, 27(2): 203-208.
Abstract:
In the wastewater infiltration land treating systems, the relation between hydraulic residence time and effects of effluent is directly associated with the relation between system scale and effects of effluent. The relation between pollutants' removals and hydraulic residence time following first order dynamic equation is commonly accepted. This paper further discusses this question from the point of microorganism increasing dynamics.Resultsshow that, strictly speaking, the relation between concentrations of different pollutants in effluent and hydraulic residence time is an analogous exponential relation, but actually, its curve shows a superposition of a straight line and a negative exponential curve, but not a pure negative exponential curve. Application results verify that, treating efficiency of different systems can be compared and evaluated by the first order rate constants, KT. To improve the treating efficiency and reduce the land using and investment, we can adopt measures to improve the activities of microorganisms around the first order rate constants, KT, integrated indexes reflecting the purifying capability of different systems.
In the wastewater infiltration land treating systems, the relation between hydraulic residence time and effects of effluent is directly associated with the relation between system scale and effects of effluent. The relation between pollutants' removals and hydraulic residence time following first order dynamic equation is commonly accepted. This paper further discusses this question from the point of microorganism increasing dynamics.Resultsshow that, strictly speaking, the relation between concentrations of different pollutants in effluent and hydraulic residence time is an analogous exponential relation, but actually, its curve shows a superposition of a straight line and a negative exponential curve, but not a pure negative exponential curve. Application results verify that, treating efficiency of different systems can be compared and evaluated by the first order rate constants, KT. To improve the treating efficiency and reduce the land using and investment, we can adopt measures to improve the activities of microorganisms around the first order rate constants, KT, integrated indexes reflecting the purifying capability of different systems.
2002, 27(2): 209-211.
Abstract:
According to the intensity peculiarity of soil body and the assumption that the destroyed bodies by abrupt gush are cuboids or cylinders, the writer deduced a calculation formula of stability of the abrupt gush of soil and water concerned about the above. And the calculation result manifests that, for generic cohesive soil, the partial safety factor of resistance, taken intensity into account, are over three times of those not done. No abrupt gush phenomena have come about in digging of building foundation pits in Hankou district, which demonstrates that the intensity of resistive shearing has a not to be neglectable effect on resistance. So the stability analyses of abrupt gush concerned about intensity of the soil body are relatively close to engineering reality.
According to the intensity peculiarity of soil body and the assumption that the destroyed bodies by abrupt gush are cuboids or cylinders, the writer deduced a calculation formula of stability of the abrupt gush of soil and water concerned about the above. And the calculation result manifests that, for generic cohesive soil, the partial safety factor of resistance, taken intensity into account, are over three times of those not done. No abrupt gush phenomena have come about in digging of building foundation pits in Hankou district, which demonstrates that the intensity of resistive shearing has a not to be neglectable effect on resistance. So the stability analyses of abrupt gush concerned about intensity of the soil body are relatively close to engineering reality.
2002, 27(2): 212-216.
Abstract:
At present, no perfect calculation method has been found for the freeway soft foundation instant settlement quality. This paper tries to establish a calculation formula of the freeway instant settlement quality in Zhujiang delta area by starting with the main factors leading to shear deformation, and considering soil structure damage and sand well restraining displacement of soft foundation. Two calculation formulas have been obtained according to the loading larger than P c and the loading smaller than P c. Also experience coefficient was attained by the analysis of the practical data. The engineering example proves that this method is credible.
At present, no perfect calculation method has been found for the freeway soft foundation instant settlement quality. This paper tries to establish a calculation formula of the freeway instant settlement quality in Zhujiang delta area by starting with the main factors leading to shear deformation, and considering soil structure damage and sand well restraining displacement of soft foundation. Two calculation formulas have been obtained according to the loading larger than P c and the loading smaller than P c. Also experience coefficient was attained by the analysis of the practical data. The engineering example proves that this method is credible.
2002, 27(2): 217-221.
Abstract:
In this paper, the model is established for evolution sensitive factors for controlling geological hazards: lithology, geological structure, slope degree of landform, human engineering activity, based on the specific geographic and geological environmental conditions in Xianju county. The comprehensive criteria of fuzzy mathematics is used for the geological hazards division. Finally, the development plan of geological environment is put forward according to the evaluation results.
In this paper, the model is established for evolution sensitive factors for controlling geological hazards: lithology, geological structure, slope degree of landform, human engineering activity, based on the specific geographic and geological environmental conditions in Xianju county. The comprehensive criteria of fuzzy mathematics is used for the geological hazards division. Finally, the development plan of geological environment is put forward according to the evaluation results.
2002, 27(2): 222-226.
Abstract:
This paper takes Hebei DSS (decision support system) for groundwater study and presents how to develop a DSS for groundwater on the basis of GIS platform, according to the concrete demands of groundwater management and decision making. The paper systematically expatiates on the selection of system platform, design of the DSS frame and elements of geodatabase, especially the development and design of the modelbase. This study case can supply some good ideas for the similar systems in other regions.
This paper takes Hebei DSS (decision support system) for groundwater study and presents how to develop a DSS for groundwater on the basis of GIS platform, according to the concrete demands of groundwater management and decision making. The paper systematically expatiates on the selection of system platform, design of the DSS frame and elements of geodatabase, especially the development and design of the modelbase. This study case can supply some good ideas for the similar systems in other regions.
2002, 27(2): 227-230.
Abstract:
The studying area is the recharge area of shallow groundwater. The results indicate that the chloroaliphatic hydrocarbons (CAHs) from landfill leathates is mainly distributed in the middle of the area. The seasonal characteristics of CAHs occurrence and concentration can be well correlated with the distance and the age of landfills, which decrease with the distance and increase with the age. The article discusses the characteristics of CAHs in groundwater contaminated from landfill leachates in two aspects: vulnerability to contamination of groundwater and contamination mechanism.
The studying area is the recharge area of shallow groundwater. The results indicate that the chloroaliphatic hydrocarbons (CAHs) from landfill leathates is mainly distributed in the middle of the area. The seasonal characteristics of CAHs occurrence and concentration can be well correlated with the distance and the age of landfills, which decrease with the distance and increase with the age. The article discusses the characteristics of CAHs in groundwater contaminated from landfill leachates in two aspects: vulnerability to contamination of groundwater and contamination mechanism.
2002, 27(2): 231-234.
Abstract:
Reservoir side rebuilding is a major problem that often arises in hydraulic and hydroelectric engineering, but there are no effective methods to forecast quantitatively the reservoir side rebuilding of rock shore. This paper introduces the analogy method with stable slide shape that can be used to predict the final width of the shore rebuilding. The method has been applied in forecasting the reservoir side rebuilding of a new town in the reservoir area of Three Gorges Project, and has produced perfect results. Hence it can be used for the planning and building of the new town.
Reservoir side rebuilding is a major problem that often arises in hydraulic and hydroelectric engineering, but there are no effective methods to forecast quantitatively the reservoir side rebuilding of rock shore. This paper introduces the analogy method with stable slide shape that can be used to predict the final width of the shore rebuilding. The method has been applied in forecasting the reservoir side rebuilding of a new town in the reservoir area of Three Gorges Project, and has produced perfect results. Hence it can be used for the planning and building of the new town.
2002, 27(2): 235-240.
Abstract:
This paper discusses the concepts and characterization of environmental risk for industrial projects to occur. It also expoundes and determines the environmental risk and its assessment standard-receivable level. Finally, it presentes steps and method of environmental risk assessment for industrial constructions.
This paper discusses the concepts and characterization of environmental risk for industrial projects to occur. It also expoundes and determines the environmental risk and its assessment standard-receivable level. Finally, it presentes steps and method of environmental risk assessment for industrial constructions.
