2003 Vol. 11, No. 2

论文
The anti-slip stability of high arc dam shoulders depends on the development of lateral crack planes boundaries. In many cases, these cracks consist of joints in random distribution. So it is of very important engineering significance to find out the characteristics of the joints for stability analysis and design of dam shoulders. In this paper, taking a designed high arc dam located in southwestern China as an example, the authors make a systematic quantitative description of the joints system at the damsite. Several tens thousands of data about the joints were collected in extensive field investigation. These data were analyzed carefully and all features, such us joints distribution, geometry and structures were picked up. Based on these features, a distribution model was quantitatively set up and an engineering of zoning of joints is suggested, which gave a clear and visual expression of the joints development and the state of the lateral crack planes, especially the general exsistence of joints for anti-slip stability of the dam shoulder. Finally, the condition of anti-slip stability of the dam shoulders was assessed in terms of the joints model presented in this paper. The anti-slip stability of high arc dam shoulders depends on the development of lateral crack planes boundaries. In many cases, these cracks consist of joints in random distribution. So it is of very important engineering significance to find out the characteristics of the joints for stability analysis and design of dam shoulders. In this paper, taking a designed high arc dam located in southwestern China as an example, the authors make a systematic quantitative description of the joints system at the damsite. Several tens thousands of data about the joints were collected in extensive field investigation. These data were analyzed carefully and all features, such us joints distribution, geometry and structures were picked up. Based on these features, a distribution model was quantitatively set up and an engineering of zoning of joints is suggested, which gave a clear and visual expression of the joints development and the state of the lateral crack planes, especially the general exsistence of joints for anti-slip stability of the dam shoulder. Finally, the condition of anti-slip stability of the dam shoulders was assessed in terms of the joints model presented in this paper.
With the development of urban construction, we will face a lot of geologic hazard problems. The losses would be great as these hazards occur, and a large amount of money will be needed to prevent them. The paper begins with the economic analysis of the geotechnical engineering problems in urban construction, and then makes a further study on the cost of urban construction. It would be of great importance in urban planning, construction and management. With the development of urban construction, we will face a lot of geologic hazard problems. The losses would be great as these hazards occur, and a large amount of money will be needed to prevent them. The paper begins with the economic analysis of the geotechnical engineering problems in urban construction, and then makes a further study on the cost of urban construction. It would be of great importance in urban planning, construction and management.
In recent years, with increasing urban population, the conditions of communications and accommodations become more and more crowded. In some medium- sized or huge cities in our country, the number of underground engineering projects, such as communication tunnels,subways and underground markets increases year after year. Because of the pecularities of urban engineering circumstance and the characters of underground engineering projects, a series of environmental geotechnical problems, such as instability of foundation pit, ground subsidence,karst collapse, instability of cave and water irruption become more conspicuous and frequent. They seriously affect not only the construction of underground engineering projects and safety of buildings around, but also cause huge economic loss to the whole country. The problems have attract attention of experts in the geotechnical area and become the key study subject in the area. In combination with the practical constructions in Nanjing, the authors discuss the characters and mechanism of environmental geotechnical problems of urban underground engineering. At the same time, some suggestions and methods for solving the environmental geotechnical problems are given in the paper. In recent years, with increasing urban population, the conditions of communications and accommodations become more and more crowded. In some medium- sized or huge cities in our country, the number of underground engineering projects, such as communication tunnels,subways and underground markets increases year after year. Because of the pecularities of urban engineering circumstance and the characters of underground engineering projects, a series of environmental geotechnical problems, such as instability of foundation pit, ground subsidence,karst collapse, instability of cave and water irruption become more conspicuous and frequent. They seriously affect not only the construction of underground engineering projects and safety of buildings around, but also cause huge economic loss to the whole country. The problems have attract attention of experts in the geotechnical area and become the key study subject in the area. In combination with the practical constructions in Nanjing, the authors discuss the characters and mechanism of environmental geotechnical problems of urban underground engineering. At the same time, some suggestions and methods for solving the environmental geotechnical problems are given in the paper.
Low permeable media are the ideal natural barrier resisting the underground migration of harmful materials. So it becomes the first selected host rock for high-level radioactive waste disposal repository. In review of the hydrogeological research related to the sitting of the disposal repository, the characteristics of geological study of low permeable media are described in the paper. Several problems, such as measurement of geological parameters, groundwater sampling, water flow modeling and geochemical modeling, are presented in detail. Low permeable media are the ideal natural barrier resisting the underground migration of harmful materials. So it becomes the first selected host rock for high-level radioactive waste disposal repository. In review of the hydrogeological research related to the sitting of the disposal repository, the characteristics of geological study of low permeable media are described in the paper. Several problems, such as measurement of geological parameters, groundwater sampling, water flow modeling and geochemical modeling, are presented in detail.
An in-site micro-penetration test on the tidal flat(20m20m) and laboratory granulometric analysis indicate that physical and engineering-mechanical properties of soil on the Yellow River Delta are inhomogeneous in small-scale space. The inhomogeneous properties have an important effect on the formation of slope micromorphology on the Yellow River Delta. An in-site micro-penetration test on the tidal flat(20m20m) and laboratory granulometric analysis indicate that physical and engineering-mechanical properties of soil on the Yellow River Delta are inhomogeneous in small-scale space. The inhomogeneous properties have an important effect on the formation of slope micromorphology on the Yellow River Delta.
The weak structural plane is an important engineering-geological problem in construction of hydroelectric project. To choose rational mechanical parameters is of great significance for determining the dam foundation surface and the stability against sliding. In this paper, the correlation between granulometric composition and shear strength parameter weak interlayer in sedimentary rocks is studied, and the correlation equations are established for different consistency states. Finally, in combination with quantitative indexes determinied in the code for Design of Concrete Gravity Dams, the shear strength parameters of weak structural plane are determinied. The weak structural plane is an important engineering-geological problem in construction of hydroelectric project. To choose rational mechanical parameters is of great significance for determining the dam foundation surface and the stability against sliding. In this paper, the correlation between granulometric composition and shear strength parameter weak interlayer in sedimentary rocks is studied, and the correlation equations are established for different consistency states. Finally, in combination with quantitative indexes determinied in the code for Design of Concrete Gravity Dams, the shear strength parameters of weak structural plane are determinied.
This paper deals with the experimental result of dynamic compaction of soft silt foundation on southern bank of Qiantangjiang River and physical and mechanical properties, deformation character, liquefaction capability, and other static and dynamic characteristics before and after dynamic compaction with different energy. This paper deals with the experimental result of dynamic compaction of soft silt foundation on southern bank of Qiantangjiang River and physical and mechanical properties, deformation character, liquefaction capability, and other static and dynamic characteristics before and after dynamic compaction with different energy.
From the test result of soft sediments, a mechanical model for creeping of the test sediments is proposed and deformation mechanism is discussed。According to time effect of long-term strength of soft sediments, the dynamic stability of slopes on Fuxin-Haizhou Open-pit Coal Mine is studied, and a method for predicting the instability of this kind of slopes is discussed. From the test result of soft sediments, a mechanical model for creeping of the test sediments is proposed and deformation mechanism is discussed。According to time effect of long-term strength of soft sediments, the dynamic stability of slopes on Fuxin-Haizhou Open-pit Coal Mine is studied, and a method for predicting the instability of this kind of slopes is discussed.
A risk will arise from the construction of tunnel if the frontal geologic circumstance is unkonwn. In order to solve this problem, the method for geological prediction is used. The practice of construction of Changliangshan Tunnel has comfirmed the importance of the geological prediction. A risk will arise from the construction of tunnel if the frontal geologic circumstance is unkonwn. In order to solve this problem, the method for geological prediction is used. The practice of construction of Changliangshan Tunnel has comfirmed the importance of the geological prediction.
The study suggests that one of the most important factors causing ground subsidence is the over-pumping groundwater in the Suzhou-Xishan-Changzhou region. Water pumping in Xishan City is most intense and hence damage from the ground subsidence is also most heavy. In order to effectively analysis and study of the process of occurence and development of ground subsidence, it is necessary to obtain observation data of ground subsidence for a certain long time. Global positioning system(GPS) is an ecnomic and high-effective approach. After a brief account of geology, hydrogeology and development and utilizatoin of groundwater in the Xishan city in the paper, a stress is put on the first observation of ground subsidence in the city by using GPS technique and the obtained data are systematically analyzed. Finally, the development history and current status of the ground subsidence in the city are preliminarily discussed. The study suggests that one of the most important factors causing ground subsidence is the over-pumping groundwater in the Suzhou-Xishan-Changzhou region. Water pumping in Xishan City is most intense and hence damage from the ground subsidence is also most heavy. In order to effectively analysis and study of the process of occurence and development of ground subsidence, it is necessary to obtain observation data of ground subsidence for a certain long time. Global positioning system(GPS) is an ecnomic and high-effective approach. After a brief account of geology, hydrogeology and development and utilizatoin of groundwater in the Xishan city in the paper, a stress is put on the first observation of ground subsidence in the city by using GPS technique and the obtained data are systematically analyzed. Finally, the development history and current status of the ground subsidence in the city are preliminarily discussed.
Chengdu Nanchong expressway on the mileage from K72+900 to K73+300 passes through a weak foundation, on which the high embankment must be constructed .The bearing capacity of the roadbed is very low, and is not satisfied the requirement of design .In order to improve the bearing capacity of the weak foundation, polytechnical method, including gravel column compound foundation, plastic drain slab and sand-gravel padding are adopted. The engineering practice proves that effectiveness of these methods is very good .This paper summarizes the construction technology, engineering quality control and examination techniques. The result introduced in this paper will have good used in future engineering . Chengdu Nanchong expressway on the mileage from K72+900 to K73+300 passes through a weak foundation, on which the high embankment must be constructed .The bearing capacity of the roadbed is very low, and is not satisfied the requirement of design .In order to improve the bearing capacity of the weak foundation, polytechnical method, including gravel column compound foundation, plastic drain slab and sand-gravel padding are adopted. The engineering practice proves that effectiveness of these methods is very good .This paper summarizes the construction technology, engineering quality control and examination techniques. The result introduced in this paper will have good used in future engineering .
There are more than 4700 debris flow hazards along the main traffic lines of railway and highway in western China, which account for 70 percent of the debris flows along traffic lines in the whole country. Debris flows are distributed extensively, frequently cause serious damage and losses in traffic construction in western China region. A large number of studies and investigations, six measures for controlling debris flows in the paper, which are correctly distinguishing debris flow gullies and their development process strictly choosing suitable route, engineering design in donsideration of the characteristics of debris flow, rising survey and design level for mitigating and preventing disaster,and carrying out debris flow prevention testing and demonstrating works. There are more than 4700 debris flow hazards along the main traffic lines of railway and highway in western China, which account for 70 percent of the debris flows along traffic lines in the whole country. Debris flows are distributed extensively, frequently cause serious damage and losses in traffic construction in western China region. A large number of studies and investigations, six measures for controlling debris flows in the paper, which are correctly distinguishing debris flow gullies and their development process strictly choosing suitable route, engineering design in donsideration of the characteristics of debris flow, rising survey and design level for mitigating and preventing disaster,and carrying out debris flow prevention testing and demonstrating works.
Red clay gravel bed in Guilin area attracts many attentions to its engineering-geological characteracteristics. But its genesis is still in controversy. In this paper a discussion is made on the engineering use of the red clay gravel bed. It can be used as natural foundation supporting low-story buildings or as filling of lowland,such as,ditch, pond, hallow and gully. If the bed is thick enough, its hard part can be used as support layer of pile foundation. Red clay gravel bed in Guilin area attracts many attentions to its engineering-geological characteracteristics. But its genesis is still in controversy. In this paper a discussion is made on the engineering use of the red clay gravel bed. It can be used as natural foundation supporting low-story buildings or as filling of lowland,such as,ditch, pond, hallow and gully. If the bed is thick enough, its hard part can be used as support layer of pile foundation.
There are many earth-structure sites in the arid areas of Northwest China, some of them are world cultural eritages. But it is regretful that they were eroded and deflated under the specific climate in the areas and damaged are very seriously. It is fairly necessary to study reinforcement of the earth-structure sites. Potassium silicate is an inorganic cementing-reinforcing material of aqueous solution. In this paper, a reinforcing technique for ancient earth-structure sites is described in detail and the mechanism for the reinforcement is preliminarily discussed. On the bassis of our practice, we conside that the potassium silicate is an effective material for reinforcement of earth-structure sites in the arid Northwest China and has an ideal effectiveness. It should be put into practice in the future. There are many earth-structure sites in the arid areas of Northwest China, some of them are world cultural eritages. But it is regretful that they were eroded and deflated under the specific climate in the areas and damaged are very seriously. It is fairly necessary to study reinforcement of the earth-structure sites. Potassium silicate is an inorganic cementing-reinforcing material of aqueous solution. In this paper, a reinforcing technique for ancient earth-structure sites is described in detail and the mechanism for the reinforcement is preliminarily discussed. On the bassis of our practice, we conside that the potassium silicate is an effective material for reinforcement of earth-structure sites in the arid Northwest China and has an ideal effectiveness. It should be put into practice in the future.
Centrifugal Model Test (CMT)is playing a more and more important role in engineering construction nowadays beacuse it can simulate the self-gravity stress field directly. In this paper, the fundamental principle, the characteristics and the current status of CMT is briefly introduced, then its application to coal mineis discussed in detail. Furthermore, the process of coal mining is simulated with CMT. Finally the problems existingin CMT are pointed out and the direction for its further development was given. Centrifugal Model Test (CMT)is playing a more and more important role in engineering construction nowadays beacuse it can simulate the self-gravity stress field directly. In this paper, the fundamental principle, the characteristics and the current status of CMT is briefly introduced, then its application to coal mineis discussed in detail. Furthermore, the process of coal mining is simulated with CMT. Finally the problems existingin CMT are pointed out and the direction for its further development was given.
The Manla Hydro-Junction Project in Tibet is located on the high plateau area with high earthquake intensity. There are large-scale landslides existing within up-and down-streams near the hydro-Junction site on the left bank,which have a potential threat to the project.Therefore,a special investigation and an experimental test has been done on the landslides on left bank and a deformation monitoring network has been set up and covered the landslides. The deformation data were collected during the reservoir construction and imponding and early operation stage of the project. Analysis of the deformation data permitted us to predict the possible slip of the landslides. The reuslt is very important for the safety of the Manla Hydro-Junction. The Manla Hydro-Junction Project in Tibet is located on the high plateau area with high earthquake intensity. There are large-scale landslides existing within up-and down-streams near the hydro-Junction site on the left bank,which have a potential threat to the project.Therefore,a special investigation and an experimental test has been done on the landslides on left bank and a deformation monitoring network has been set up and covered the landslides. The deformation data were collected during the reservoir construction and imponding and early operation stage of the project. Analysis of the deformation data permitted us to predict the possible slip of the landslides. The reuslt is very important for the safety of the Manla Hydro-Junction.
Based on the investigation of regional seismic activity, engineering-geological conditions, and rock mass loading boundaries, and on the measuring physical and mechanical parameters of the collected samples in laboratory, this paper a three-dimensional (3-D) numerical modelingmethod is used in quantitative analysis of slopes at different conditions (natural, saturated and saturated and shaking states) and to evaluate the stability of the slopes. Then some suggestions are made to engineering construction. Based on the investigation of regional seismic activity, engineering-geological conditions, and rock mass loading boundaries, and on the measuring physical and mechanical parameters of the collected samples in laboratory, this paper a three-dimensional (3-D) numerical modelingmethod is used in quantitative analysis of slopes at different conditions (natural, saturated and saturated and shaking states) and to evaluate the stability of the slopes. Then some suggestions are made to engineering construction.
The Danjiangkou Reservoir is not a reliable stable base for water source,the Yellow River flow is frequently cut out and the Weihe River has lack of water. These problems can not be solved in present scheme of the East and Middle lines of S-N water diversion, but can be solved in the new line scheme, which is of great benefit. This paper deals with geology and engineering-geological condition of the new line. No technical and geological problems can not be solved in implementation of this line scheme. The Danjiangkou Reservoir is not a reliable stable base for water source,the Yellow River flow is frequently cut out and the Weihe River has lack of water. These problems can not be solved in present scheme of the East and Middle lines of S-N water diversion, but can be solved in the new line scheme, which is of great benefit. This paper deals with geology and engineering-geological condition of the new line. No technical and geological problems can not be solved in implementation of this line scheme.
Great challenges have been encountered in the construction of Fenghuoshan Tunnel for its chilly climate and plateau condition. The difficulties are how to construct the tunnel without harm to frozen soils; how to use special techniques to adapt to the absence of oxygen in the plateau. A series of techniques have been adopted to overcome these difficulties, the tunnel is sucessfully constructed eventually. Great challenges have been encountered in the construction of Fenghuoshan Tunnel for its chilly climate and plateau condition. The difficulties are how to construct the tunnel without harm to frozen soils; how to use special techniques to adapt to the absence of oxygen in the plateau. A series of techniques have been adopted to overcome these difficulties, the tunnel is sucessfully constructed eventually.
Engineering geological study is aimed at maximal adoption to and protection of the environment by engineering construction and running: holism of nature-human being. So its theoretical kernel-interaction between engineering and the environment, and its objects include natural engineering geological conditions and the environment geological action and environment effects of engineering, i.e.. artificial geological phenomena, especially, possible artificial geological disasters. All these studies should be carried out from region to construction site to region again, from depth to shallow part to depth again(view of control by region and depth, view of expansion of enviromental effects), from history to present condition to near and distant future(view of natural and artificial history); Whereas the study on environmental effects of engineering-from one to all(without omission)to most important one (to stress the main points):holism of time-space-state. Microscopically, rock mass-soil mass structure mechanical study, rock mass-soil mass hydraulical study and rock-soil-water-gas physico-chemical study should be developed simultaneously with emphasis on structure mechanicsl study. Macroscopically, studies from view point of geoscience, environmtnal science, engineering science and system science should be developed simultaneously with emphasis on study from view point of geoscience: holism of macro-microscopic studies. On the basis of all these studies geological, mechanical, mathematical and management models are estabilished step by step. These models are solved and realized with development and application of exploration, testing, physical and digital, simulation, prediction, monitoring, management techniques:holism of ends-means. Based on above-stated, a system of engineering geology, the status of engineering geology as branch of learning, setting up of research and education organizations, and training of specialists-engineering geologists are suggested in this paper. Engineering geological study is aimed at maximal adoption to and protection of the environment by engineering construction and running: holism of nature-human being. So its theoretical kernel-interaction between engineering and the environment, and its objects include natural engineering geological conditions and the environment geological action and environment effects of engineering, i.e.. artificial geological phenomena, especially, possible artificial geological disasters. All these studies should be carried out from region to construction site to region again, from depth to shallow part to depth again(view of control by region and depth, view of expansion of enviromental effects), from history to present condition to near and distant future(view of natural and artificial history); Whereas the study on environmental effects of engineering-from one to all(without omission)to most important one (to stress the main points):holism of time-space-state. Microscopically, rock mass-soil mass structure mechanical study, rock mass-soil mass hydraulical study and rock-soil-water-gas physico-chemical study should be developed simultaneously with emphasis on structure mechanicsl study. Macroscopically, studies from view point of geoscience, environmtnal science, engineering science and system science should be developed simultaneously with emphasis on study from view point of geoscience: holism of macro-microscopic studies. On the basis of all these studies geological, mechanical, mathematical and management models are estabilished step by step. These models are solved and realized with development and application of exploration, testing, physical and digital, simulation, prediction, monitoring, management techniques:holism of ends-means. Based on above-stated, a system of engineering geology, the status of engineering geology as branch of learning, setting up of research and education organizations, and training of specialists-engineering geologists are suggested in this paper.