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Editor Work2006 Vol. 14, No. 6
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2006, 14(6): 721-727.
Abstract
This paper analyzes the historical trends of urbanization in the world and history and evolution of urban developments and urbanization in China.On the basis of the analysis,it discusses the trends and developments of engineering geology including the areas of geological environment and urban planning,urban underground space utilization,urban ecology,and environmental safety.It emphasizes an innovative development approach by taking into account of geological basic research,multiple disciplines,multiple knowlodge as well as multiple technology combinations.
This paper analyzes the historical trends of urbanization in the world and history and evolution of urban developments and urbanization in China.On the basis of the analysis,it discusses the trends and developments of engineering geology including the areas of geological environment and urban planning,urban underground space utilization,urban ecology,and environmental safety.It emphasizes an innovative development approach by taking into account of geological basic research,multiple disciplines,multiple knowlodge as well as multiple technology combinations.
2006, 14(6): 728-733.
A review on the study of geological environment and city development is presented in this paper.The problems of urban engineering geological work in our country are pointed out and the way to solve it is proved.Some suggestions are put forward to improve the research and work of geological environment and city development in our country.A related topic about engineering geology education in our country is introduced.
A review on the study of geological environment and city development is presented in this paper.The problems of urban engineering geological work in our country are pointed out and the way to solve it is proved.Some suggestions are put forward to improve the research and work of geological environment and city development in our country.A related topic about engineering geology education in our country is introduced.
2006, 14(6): 734-738.
This paper presents a review report of the papers on urban geological environment and engineering presented at the 2006 annaul conference of the Engineering Geology Committee of China Geology Society.It includes basic geological mapping of urban area,engineering geological condition assessment,relevant information technologies.It briefly reports some of the papers.It further gives detailed reporting on engineering geology condition evaluation and related issures.Furthermore,it dicusses the future trends of the relevant issues and problems.
This paper presents a review report of the papers on urban geological environment and engineering presented at the 2006 annaul conference of the Engineering Geology Committee of China Geology Society.It includes basic geological mapping of urban area,engineering geological condition assessment,relevant information technologies.It briefly reports some of the papers.It further gives detailed reporting on engineering geology condition evaluation and related issures.Furthermore,it dicusses the future trends of the relevant issues and problems.
2006, 14(6): 739-742.
Based on the papers presented at the conference of urban geological environment and engineering,this paper summarizes the current status and developments of urban environmental geology in China.It suggests some problems for research and investigation in future.
Based on the papers presented at the conference of urban geological environment and engineering,this paper summarizes the current status and developments of urban environmental geology in China.It suggests some problems for research and investigation in future.
2006, 14(6): 743-748.
In recent years,more and more loess slopes are excavated in Northwestern China.The instability of slopes affects the engineering facilities,so it is important to study the deformation mechanism and design reasonable stabilization countermeasures.This paper examines the deformation mechanism of one counter-tilt slope composed of sandstone and mudstone with loess covering and fault zone passing through.Based on analysis of engineering geological conditions and deformation characters,the slope deformation mechanism is studied.Three-dimension geological model is established to analyze the distribution of stress and strain of slope.Flac-3D software is used to simulate the excavation process of the loess slope.The numerical result indicates that large area tension stress distributes in fault and loess at upper slope.The rock mass in counter-tilt fault moves along the fault.,Shearing deformation generates in the lower slope along interface between bedrock and loess and develops upward.The pull-type deformation occurs in loess at the upper slope under this type of stress state.Therefore,the control of the slope deformation should concentrate on improvement of the stress state with unloading and controlling deformation of interface between bedrock and loess.At last,the control measures include offloading,steel pile,anchor and slope protection.
In recent years,more and more loess slopes are excavated in Northwestern China.The instability of slopes affects the engineering facilities,so it is important to study the deformation mechanism and design reasonable stabilization countermeasures.This paper examines the deformation mechanism of one counter-tilt slope composed of sandstone and mudstone with loess covering and fault zone passing through.Based on analysis of engineering geological conditions and deformation characters,the slope deformation mechanism is studied.Three-dimension geological model is established to analyze the distribution of stress and strain of slope.Flac-3D software is used to simulate the excavation process of the loess slope.The numerical result indicates that large area tension stress distributes in fault and loess at upper slope.The rock mass in counter-tilt fault moves along the fault.,Shearing deformation generates in the lower slope along interface between bedrock and loess and develops upward.The pull-type deformation occurs in loess at the upper slope under this type of stress state.Therefore,the control of the slope deformation should concentrate on improvement of the stress state with unloading and controlling deformation of interface between bedrock and loess.At last,the control measures include offloading,steel pile,anchor and slope protection.
2006, 14(6): 749-755.
In this paper the hydrogeological and engineering geological condition are analyzed in detail.According to the design plan of Longzi Lake,the problem of large seepage volume might occur after the completion of the lake project.The groundwater level might rise because of the seepage of Longzi Lake and it might influence the entironment surrounding the lake.A three dimensional model of seepage simulation was established and the results of the computation proved the problem of large seepage volume to be true.Alternative plans are put forward which may help to solve the problem.Other new problems due to the change of the hydrogeological and engineering geological conditions are forecasted and analyzed.Finally,the methods to solve the problem are advised.
In this paper the hydrogeological and engineering geological condition are analyzed in detail.According to the design plan of Longzi Lake,the problem of large seepage volume might occur after the completion of the lake project.The groundwater level might rise because of the seepage of Longzi Lake and it might influence the entironment surrounding the lake.A three dimensional model of seepage simulation was established and the results of the computation proved the problem of large seepage volume to be true.Alternative plans are put forward which may help to solve the problem.Other new problems due to the change of the hydrogeological and engineering geological conditions are forecasted and analyzed.Finally,the methods to solve the problem are advised.
2006, 14(6): 756-762.
Shanyin-Pinglu expressway is one part of the key state expressway,Weihai-Wuhai expressway.According to the 1:10,000 comprehensive geological investigation results along the corridor of the expressway and based on the illustration and analysis of the engineering geological environment and disasters along the three pre-selected lines,the engineering stability for each line is comprehensively evaluated and line A is recommended to be optimal.
Shanyin-Pinglu expressway is one part of the key state expressway,Weihai-Wuhai expressway.According to the 1:10,000 comprehensive geological investigation results along the corridor of the expressway and based on the illustration and analysis of the engineering geological environment and disasters along the three pre-selected lines,the engineering stability for each line is comprehensively evaluated and line A is recommended to be optimal.
2006, 14(6): 763-768.
In this paper the geographical position of the Huaying Mountain is described,and the mountainous region gravity disasters occurring in the Huaying Mountain area in recent years are comprehensively introduced.It is noticeable that the influence of mountainous region gravity disasters is quite significant in this area,and it has already became the main type of disaster in local area.Through various aspects of investigations and researches,with the integration of scientific analyses and empirical experiences,the various factors which cause the mountainous region gravity disasters are analyzed,and the origin of Huaying mountainous region gravity disasters is analyzed mainly from the perspectives of geology,hydrology and human activities.The possible external factors and internal factors which induce the mountainous region gravity disasters are summarised.It is obvious that the mountainous region gravity disasters are not merely caused by one factor,but by the mutual influence of multiple factors.As a result,various kinds of measures should be taken to prevent the disasters and reduce the consequent influence to people's work and life.
In this paper the geographical position of the Huaying Mountain is described,and the mountainous region gravity disasters occurring in the Huaying Mountain area in recent years are comprehensively introduced.It is noticeable that the influence of mountainous region gravity disasters is quite significant in this area,and it has already became the main type of disaster in local area.Through various aspects of investigations and researches,with the integration of scientific analyses and empirical experiences,the various factors which cause the mountainous region gravity disasters are analyzed,and the origin of Huaying mountainous region gravity disasters is analyzed mainly from the perspectives of geology,hydrology and human activities.The possible external factors and internal factors which induce the mountainous region gravity disasters are summarised.It is obvious that the mountainous region gravity disasters are not merely caused by one factor,but by the mutual influence of multiple factors.As a result,various kinds of measures should be taken to prevent the disasters and reduce the consequent influence to people's work and life.
2006, 14(6): 769-775.
Lixiahe district,where the Huaiyan expressway runs,has broadly distribution of high water-content and high compressive ancient lagoon facies soft soil.The soil has engineering low-grade properties.There is a close relationship between its engineering properties and the development mechanism of Lixiahe lagoon.In this paper,it starts from changes of the sedimentary environment and local geology,points out the development mechanism of Lixiahe lagoon facies soft soil,based on the general development model of lagoon.After these,it analyzes the engineering properties of typical lagoon facies soft soil from Huaiyan expressway,and estimates the distribution of lagoon facies soft soil based on the vertical changes of its engineering properties.Finally,the paper gives the relationship between its engineering properties and growth mechanism.
Lixiahe district,where the Huaiyan expressway runs,has broadly distribution of high water-content and high compressive ancient lagoon facies soft soil.The soil has engineering low-grade properties.There is a close relationship between its engineering properties and the development mechanism of Lixiahe lagoon.In this paper,it starts from changes of the sedimentary environment and local geology,points out the development mechanism of Lixiahe lagoon facies soft soil,based on the general development model of lagoon.After these,it analyzes the engineering properties of typical lagoon facies soft soil from Huaiyan expressway,and estimates the distribution of lagoon facies soft soil based on the vertical changes of its engineering properties.Finally,the paper gives the relationship between its engineering properties and growth mechanism.
2006, 14(6): 776-781.
Free swelling ratio is a frequent index for classification and identification of expansive soils in highway and other professions.In the HeFei-LuAn expressway,test studies on the free swelling ratio and related indices are carried.The characteristics are analysed.The results indicate that the free swelling ratio of expansive soil in the middle of AnHui province is lower than the average level of China.Its relationship with smectite content is preferable.Its relationship with liquid limit and plastic index are good too.These indices can be integrated for classification and identification of expansive soils.By means of practice of identification,the results show that the consistence can't be got using a single index and the grading standard of free swelling ratio doesn't fit expansive soil in the middle of AnHui.A new grading standard possessing a better applicability is suggested.
Free swelling ratio is a frequent index for classification and identification of expansive soils in highway and other professions.In the HeFei-LuAn expressway,test studies on the free swelling ratio and related indices are carried.The characteristics are analysed.The results indicate that the free swelling ratio of expansive soil in the middle of AnHui province is lower than the average level of China.Its relationship with smectite content is preferable.Its relationship with liquid limit and plastic index are good too.These indices can be integrated for classification and identification of expansive soils.By means of practice of identification,the results show that the consistence can't be got using a single index and the grading standard of free swelling ratio doesn't fit expansive soil in the middle of AnHui.A new grading standard possessing a better applicability is suggested.
2006, 14(6): 782-787.
The Baiyian landslide in Fengji region,Three Gorges is a landslide without a consensus understanding among the researchers.The paper includes detailed geological mapping on the slope surface.The exploratory trench and CSAMT are also used The field data show some new findings of the landslide.At first,the integrity outcrop at the front of Jiguliang is not the landslide substance.Next,because the rock mass is connected at the two sides of Lijiagou,o Lijiagou is not the boundary of landslide.Moreover,Lujiagou is the eastern boundary of Baiyi'an landslide,and the eastern Shuijingcao is the western boundary of Baiyi'an landslide,and the Ganzilin is the upside boundary at the eastern side,and the Laocangwu platform is the rearward region of the landslide.
The Baiyian landslide in Fengji region,Three Gorges is a landslide without a consensus understanding among the researchers.The paper includes detailed geological mapping on the slope surface.The exploratory trench and CSAMT are also used The field data show some new findings of the landslide.At first,the integrity outcrop at the front of Jiguliang is not the landslide substance.Next,because the rock mass is connected at the two sides of Lijiagou,o Lijiagou is not the boundary of landslide.Moreover,Lujiagou is the eastern boundary of Baiyi'an landslide,and the eastern Shuijingcao is the western boundary of Baiyi'an landslide,and the Ganzilin is the upside boundary at the eastern side,and the Laocangwu platform is the rearward region of the landslide.
2006, 14(6): 788-791.
The paper explores several methods measuring degree of saturation in unsaturated soils.Different test methods for the degree of saturation in unsaturated soils can result in different results.According to the tests by GDS triaxial cell,the paper compares and analyzes these methods.It is pointed out that pre-assumption of soil grain volume being invariable is logical. Therefore,the change of specimen volume is equal to the change of soil specimen pore.The direct method is an effective method for measuring degree of saturation.
The paper explores several methods measuring degree of saturation in unsaturated soils.Different test methods for the degree of saturation in unsaturated soils can result in different results.According to the tests by GDS triaxial cell,the paper compares and analyzes these methods.It is pointed out that pre-assumption of soil grain volume being invariable is logical. Therefore,the change of specimen volume is equal to the change of soil specimen pore.The direct method is an effective method for measuring degree of saturation.
2006, 14(6): 792-799.
Large-scale rock caverns for storage of oil and gas are to be constructed in China.A number of engineering geological issues and challenges have come out.This paper presents a review of some case examples of storage caverns and investigations in China.It further describes two case studies that have been carried out by the authors.Based on these studies,the paper classifies engineering geological issues and associated investigations.It summarizes some engineering measures that have been adopted in practice.The findings in this paper can be useful for site selection and assessment,plan and design of underground rock caverns for storage of oil and gas.
Large-scale rock caverns for storage of oil and gas are to be constructed in China.A number of engineering geological issues and challenges have come out.This paper presents a review of some case examples of storage caverns and investigations in China.It further describes two case studies that have been carried out by the authors.Based on these studies,the paper classifies engineering geological issues and associated investigations.It summarizes some engineering measures that have been adopted in practice.The findings in this paper can be useful for site selection and assessment,plan and design of underground rock caverns for storage of oil and gas.
2006, 14(6): 800-807.
Rock and soil aggregate(RSA) is a kind of geological material which is different from rock mass and soils in physical and mehanical behaviors.Recently the study on RSA has drawn more and more attention from the engineering and geomechanical field.In this paper the term of RSA is introduced firstly.The importance of the study on RSA is proved due to RSA distributing widely in China and resulting in many engineering problems.On the other hand,this paper presents an overview of the published literature on RSA,including mechanical tests,geometric structure,numerical simulation and so on.It is shown that structural effects play an important role on the mechanical properites of RSA,and some previous studies on geometric structures and numerical simulation of RSA are instructive and positive to the future study.Finally,considering the lack of knowledge on RSA,this paper discusses and suggests the future studies on RSA.Four research orientations about RSA are put forward such as the geological origin and fabric charteristics,couplling interaction between water and RSA,3D simulation on RSA,and procedure of quickly determining the mechanical parameters of RSA;and the tentative methods of solving these problems are also suggested.
Rock and soil aggregate(RSA) is a kind of geological material which is different from rock mass and soils in physical and mehanical behaviors.Recently the study on RSA has drawn more and more attention from the engineering and geomechanical field.In this paper the term of RSA is introduced firstly.The importance of the study on RSA is proved due to RSA distributing widely in China and resulting in many engineering problems.On the other hand,this paper presents an overview of the published literature on RSA,including mechanical tests,geometric structure,numerical simulation and so on.It is shown that structural effects play an important role on the mechanical properites of RSA,and some previous studies on geometric structures and numerical simulation of RSA are instructive and positive to the future study.Finally,considering the lack of knowledge on RSA,this paper discusses and suggests the future studies on RSA.Four research orientations about RSA are put forward such as the geological origin and fabric charteristics,couplling interaction between water and RSA,3D simulation on RSA,and procedure of quickly determining the mechanical parameters of RSA;and the tentative methods of solving these problems are also suggested.
2006, 14(6): 808-814.
Many types of Karsts can be encountered when a tunnel in Karst ground was constructed.Generally the primary design classification of the surrounding rock mass should be revised according to the excavation condition.A classification methd for rock mass surrounding Karsts is put out in this paper.Several general conceptions about the rock classification are described.The classification standards are based on the correction coefficient of Karst development degree.The Wulong tunnel at Hengdong section is used as an example.The application shows that the classification with this method agrees well with the findings during the tunnel construction.In the method,the synthesis factors such as possibility of Karst development and Karst forms are considered.The method is the correction of the origin classification methodsthe rock surrounding Karsts.The method still needs to be verified in the future practice.examined.
Many types of Karsts can be encountered when a tunnel in Karst ground was constructed.Generally the primary design classification of the surrounding rock mass should be revised according to the excavation condition.A classification methd for rock mass surrounding Karsts is put out in this paper.Several general conceptions about the rock classification are described.The classification standards are based on the correction coefficient of Karst development degree.The Wulong tunnel at Hengdong section is used as an example.The application shows that the classification with this method agrees well with the findings during the tunnel construction.In the method,the synthesis factors such as possibility of Karst development and Karst forms are considered.The method is the correction of the origin classification methodsthe rock surrounding Karsts.The method still needs to be verified in the future practice.examined.
2006, 14(6): 815-818.
Soil natural thermoluminescence surveying is an accumulation method of measuring radon and it can measure radon in a long time.Its sensitivity and anomaly reoccurrence property are far better than usual methods,so it is widely used in the geological field.In prospecting for the landslide boundaries,the measurement result is obvious,which indicates that this method is economic and effective.
Soil natural thermoluminescence surveying is an accumulation method of measuring radon and it can measure radon in a long time.Its sensitivity and anomaly reoccurrence property are far better than usual methods,so it is widely used in the geological field.In prospecting for the landslide boundaries,the measurement result is obvious,which indicates that this method is economic and effective.
2006, 14(6): 819-823.
The space of discontinuities is one of important indexes which explains the distribution of discontinuities and also classifies quality of engineering rock mass.Unlike the traditional definition of discontinuities space,this paper points out that the distribution of discontinuities can be analyzed as long as the spaces of neighboring discontinuities are measured.It presents the four-type methods of classifying discontinuities to built the discontinuities series.It set up an ARIMA model of discontinuities space by means of theory of time series and provided methods of building and checking model.An actual case is studies to show that the ARIMA model is suitable.
The space of discontinuities is one of important indexes which explains the distribution of discontinuities and also classifies quality of engineering rock mass.Unlike the traditional definition of discontinuities space,this paper points out that the distribution of discontinuities can be analyzed as long as the spaces of neighboring discontinuities are measured.It presents the four-type methods of classifying discontinuities to built the discontinuities series.It set up an ARIMA model of discontinuities space by means of theory of time series and provided methods of building and checking model.An actual case is studies to show that the ARIMA model is suitable.
2006, 14(6): 830-834.
Analytic hierarchy process method is a kind of qualitative and quantitative analysis of multiplicate objective decision.Based on comprehensive analysis of multi-factors,the hierarchy structure system of engineering rock mass classification,which is constituted by four hierarchies,is established,because classification of rock mass engineering is affected by multi-factors.The paper gives in detail structure of judgment matrix of different hierarchy and process of classification.The example indicates that analytic hierarchy process method is simple,objective and effective.
Analytic hierarchy process method is a kind of qualitative and quantitative analysis of multiplicate objective decision.Based on comprehensive analysis of multi-factors,the hierarchy structure system of engineering rock mass classification,which is constituted by four hierarchies,is established,because classification of rock mass engineering is affected by multi-factors.The paper gives in detail structure of judgment matrix of different hierarchy and process of classification.The example indicates that analytic hierarchy process method is simple,objective and effective.
2006, 14(6): 835-840.
Based on the limit analysis upper bound theorem of soil plasticity mechanics and the traditional slice methods,this paper establishes the limit state equation of plasticity limit analysis slice techniques.According to the equation,the calculation formulas of reliability index are obtained. This method can achieve the change from definite value calculation to deconfirmative calculation.Moreover,the use of reliability index to evaluate slope stability has meaning of probability.
Based on the limit analysis upper bound theorem of soil plasticity mechanics and the traditional slice methods,this paper establishes the limit state equation of plasticity limit analysis slice techniques.According to the equation,the calculation formulas of reliability index are obtained. This method can achieve the change from definite value calculation to deconfirmative calculation.Moreover,the use of reliability index to evaluate slope stability has meaning of probability.
2006, 14(6): 841-846.
In this paper,the key techniques of safety reliability monitoring in subgrade construction in permafrost are provided according to the analysis of the interaction process between subgrade construction and the permafrost.The key techniques have the techniques,motoring methods and data analysis methods.The safety reliability of permafrost subgrade construction depends on the thermal stability of the permafrost around and at the bottom of the construction and the thickness of deformed road-base fill and the beneath thawed layer. Therefore,the soil temperatures at different depths under the railway base surface and the deformation of railway base fill during the annual freezing and thawing periods are the main indexes in the long-term reliability monitoring of road-base construction in the permafrost.The extreme bed natural conditions demand that the means of monitoring must be reliable,durable and flexible.This paper discusses one set of monitoring system It has been verified with field test.Besides,the paper presents a method for analyzing monitored data for enhancing the judgment of the permafrost construction reliability.
In this paper,the key techniques of safety reliability monitoring in subgrade construction in permafrost are provided according to the analysis of the interaction process between subgrade construction and the permafrost.The key techniques have the techniques,motoring methods and data analysis methods.The safety reliability of permafrost subgrade construction depends on the thermal stability of the permafrost around and at the bottom of the construction and the thickness of deformed road-base fill and the beneath thawed layer. Therefore,the soil temperatures at different depths under the railway base surface and the deformation of railway base fill during the annual freezing and thawing periods are the main indexes in the long-term reliability monitoring of road-base construction in the permafrost.The extreme bed natural conditions demand that the means of monitoring must be reliable,durable and flexible.This paper discusses one set of monitoring system It has been verified with field test.Besides,the paper presents a method for analyzing monitored data for enhancing the judgment of the permafrost construction reliability.
2006, 14(6): 847-851.
The Yangmeizhou-muyuhu Fault is situated just the inner urban area of Xiangtan City.There are many disturbance factors in process of geophysical prospecting.The site condition is not good to the use of a single geophysical method.Three methods of geophysical exploration were used to investigate and to identify the position and nature of the fault.They are the self-potential frequency method,the high density resistivity method,and the geological radar.Besides,the interpreted results from the geophysical methods are verified with logging of actual excavations It is found that the three methods have different characteristics as follows.The self-potential frequency method has the features: light equipment,exploration line layout flexibility and less interference factor.Especially it is precise to use the time-dependent data to determine fault plane location.The high density resistivity method has the features: it is easy visual observation and comparison of the fault zone;the exploration workload is extremely large;the topography has a large effect;testing in urabn area is difficult.The geological radar method has the features: image visual exploration results;high cost of equipment;topography has large effect;limited depth exploration;and the better results only for surface prospecting.
The Yangmeizhou-muyuhu Fault is situated just the inner urban area of Xiangtan City.There are many disturbance factors in process of geophysical prospecting.The site condition is not good to the use of a single geophysical method.Three methods of geophysical exploration were used to investigate and to identify the position and nature of the fault.They are the self-potential frequency method,the high density resistivity method,and the geological radar.Besides,the interpreted results from the geophysical methods are verified with logging of actual excavations It is found that the three methods have different characteristics as follows.The self-potential frequency method has the features: light equipment,exploration line layout flexibility and less interference factor.Especially it is precise to use the time-dependent data to determine fault plane location.The high density resistivity method has the features: it is easy visual observation and comparison of the fault zone;the exploration workload is extremely large;the topography has a large effect;testing in urabn area is difficult.The geological radar method has the features: image visual exploration results;high cost of equipment;topography has large effect;limited depth exploration;and the better results only for surface prospecting.
2006, 14(6): 852-855.
A coattail catastrophe model is presented.The necessary and sufficient conditions leading to slope failure are discussed.The sliding belt is assumed to be planar.The sliding belt and the upside crag body are composed of the different materials with different mechanical properties.The upside crag body is modeled as the elastic brittle material（called medium 1）;the sliding belt medium is modeled as a strain-softening material（called medium 2）.The shear stress-strain constitutive model is described by the Weibull's distribution law.In this way,a coattail catastrophe model is developed for the slope failures.Through the analysis,it is discovered that the slope steadily has a good relation with the stiffness ratio of medium 1 to medium 2.Along with increase,the 0 value that slope starts to skid reduces,and the value * of skips also reduces.At the same time,the marginal value x* increases,and the skip quantitative x changes to be smaller.
A coattail catastrophe model is presented.The necessary and sufficient conditions leading to slope failure are discussed.The sliding belt is assumed to be planar.The sliding belt and the upside crag body are composed of the different materials with different mechanical properties.The upside crag body is modeled as the elastic brittle material（called medium 1）;the sliding belt medium is modeled as a strain-softening material（called medium 2）.The shear stress-strain constitutive model is described by the Weibull's distribution law.In this way,a coattail catastrophe model is developed for the slope failures.Through the analysis,it is discovered that the slope steadily has a good relation with the stiffness ratio of medium 1 to medium 2.Along with increase,the 0 value that slope starts to skid reduces,and the value * of skips also reduces.At the same time,the marginal value x* increases,and the skip quantitative x changes to be smaller.
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