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Editor Work1993 Vol. 1, No. 2
Previous Issue
1993, 1(2): 1-13.
Abstract
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The genetic mechanism of the gently dipping structural plane in granite rock mass at Three-gorges damsite is systematically studied in the paper. Based on the field investigation, SEM and TEM analyses, and determination of inclusion temperature, the microstructural fabrics and differencial stress of rock mass at the damsite were studied in detail. With the geomechnical analysis, an inversion of data for genetic mechanism of gently dipping structural plane was made after the geomechanical physical simulation under similar conditions. Then using nonlinear FEM, the result was tested by numerical simulation. Such a comprehensive study in connection with geology, mechanics, microstructure and geomechanical, physical and numerical simulations is first carried out in the world, The result of study will satisfactory for requirements of engineering construction.
The genetic mechanism of the gently dipping structural plane in granite rock mass at Three-gorges damsite is systematically studied in the paper. Based on the field investigation, SEM and TEM analyses, and determination of inclusion temperature, the microstructural fabrics and differencial stress of rock mass at the damsite were studied in detail. With the geomechnical analysis, an inversion of data for genetic mechanism of gently dipping structural plane was made after the geomechanical physical simulation under similar conditions. Then using nonlinear FEM, the result was tested by numerical simulation. Such a comprehensive study in connection with geology, mechanics, microstructure and geomechanical, physical and numerical simulations is first carried out in the world, The result of study will satisfactory for requirements of engineering construction.
1993, 1(2): 14-23.
Fractal theory is introduced to analysis of joint net distribution and joint roughness curve. It is found that joint distribution in space and roughness curves show good self-similarity. Fractal dimension is a geometric parameter reflecting rock mass strength, rock mass damage degree, rock mass quality, and joint roughness. It can be also used in evaluation fo rock mass stability, analysis of fracture system activity, and discrimination of weathering-unloading zone.
Fractal theory is introduced to analysis of joint net distribution and joint roughness curve. It is found that joint distribution in space and roughness curves show good self-similarity. Fractal dimension is a geometric parameter reflecting rock mass strength, rock mass damage degree, rock mass quality, and joint roughness. It can be also used in evaluation fo rock mass stability, analysis of fracture system activity, and discrimination of weathering-unloading zone.
1993, 1(2): 24-31.
The significance of rock mass classification system is exponded in this paper. The proposition and basis of principle and method for the contrast and conversion of principal rock mass classification systems and some engineering examples are also presented. For convenience, the result of contrast and conversion is demonstrated in a genetal conversion table.
The significance of rock mass classification system is exponded in this paper. The proposition and basis of principle and method for the contrast and conversion of principal rock mass classification systems and some engineering examples are also presented. For convenience, the result of contrast and conversion is demonstrated in a genetal conversion table.
1993, 1(2): 32-42.
In this paper a new conception on the anisotropy of joint roughness coefficient and its size effect are put forward. From the result of qualitative analysis of fault surface morphology of various genesis in connection with the statistical result of 2180 measured joint roughness coefficient values in different directions, We describe the anisotropy of roughness coefficients of joint I and fault II and III and their size effect.
In this paper a new conception on the anisotropy of joint roughness coefficient and its size effect are put forward. From the result of qualitative analysis of fault surface morphology of various genesis in connection with the statistical result of 2180 measured joint roughness coefficient values in different directions, We describe the anisotropy of roughness coefficients of joint I and fault II and III and their size effect.
STABLE PARAMETER OF THE EARTHS CRUST AND ITS APPLICATION TO SELECTION OF IMPORTANT ENGINEERING SITES
1993, 1(2): 43-51.
Based on the plate tectonics and Hthosphere dynamics. the earths crust could be divided into different-scale landmasses according to a series of active fault systems or crustal defomation zones as boundaries, in which relative stable landmasses are called safety islands. The concept of stable parameter (△f) is suggested to express the stable state of a safety island quantitatively. Thus, it is a new method introduced for selecting and evaluating regional stability or safety of a site for important engineering project. As an example, it is applied to optimize seeking and evaluating dam sites in Heishanxia area of Huanghe River, and it is concluded that both Xiaoguangyin and Daliushu sites can be selected for high dams.
Based on the plate tectonics and Hthosphere dynamics. the earths crust could be divided into different-scale landmasses according to a series of active fault systems or crustal defomation zones as boundaries, in which relative stable landmasses are called safety islands. The concept of stable parameter (△f) is suggested to express the stable state of a safety island quantitatively. Thus, it is a new method introduced for selecting and evaluating regional stability or safety of a site for important engineering project. As an example, it is applied to optimize seeking and evaluating dam sites in Heishanxia area of Huanghe River, and it is concluded that both Xiaoguangyin and Daliushu sites can be selected for high dams.
1993, 1(2): 52-61.
In this paper, on the basis of the experience and in-situ measurement data used NATM in Chinese typical tunnel projects, in the light of system science, engineering geomechanics and rock mechanics, the theroy and methods for popularizing and appling rock stability analysis and predicting technologythe theory and practice of typical analogic analysis method(TAAM), is expounded.
In this paper, on the basis of the experience and in-situ measurement data used NATM in Chinese typical tunnel projects, in the light of system science, engineering geomechanics and rock mechanics, the theroy and methods for popularizing and appling rock stability analysis and predicting technologythe theory and practice of typical analogic analysis method(TAAM), is expounded.
1993, 1(2): 62-65.
The significance of earthquake magnitude division in the nuclear safety guide rule is discussed with emphasis on the role of determining macroearthquakes in the seismic siting of nuclear power plants. Finally, the author suggests a new starting magnitude of macroearthquakes in connection with Chinese seismological and geological Conditions.
The significance of earthquake magnitude division in the nuclear safety guide rule is discussed with emphasis on the role of determining macroearthquakes in the seismic siting of nuclear power plants. Finally, the author suggests a new starting magnitude of macroearthquakes in connection with Chinese seismological and geological Conditions.
In this paper, a new research field of engineering geology is put forward on the reliability analysis of quantitive prediction conclusions. The uncertainty, including its source, classification and finding, are discussed. A set of methods for discriminating the significance of prediction conclusions using only one prediction method and the reliability using several methods are set up. Application of these methods to prediction of collapse size of expansive soil slope shows that the accuracy of prediction is improved obviously by using this set of discrimination methods.
In this paper, a new research field of engineering geology is put forward on the reliability analysis of quantitive prediction conclusions. The uncertainty, including its source, classification and finding, are discussed. A set of methods for discriminating the significance of prediction conclusions using only one prediction method and the reliability using several methods are set up. Application of these methods to prediction of collapse size of expansive soil slope shows that the accuracy of prediction is improved obviously by using this set of discrimination methods.
1993, 1(2): 74-78.
Owing to complaxity of geological conditions and limitation of explorating work before construction, revision and alteration of the design of construction details are normal things in construction stage. Alterable Geo-design includes the following ways. First, design before construction is prepared to fully alter. Then, new geological, deformation and failure informations and their engineering significance are fed back immediately. Last, according to these, the design is altered and revised with the assistance of CAD and returns to construction repidly. The authors take some real engineering examples to illustrate that feeding back and analysing these informations and ensuring normal flow of them are the key for optimum design. It is necessary to bring the design into design norm formally.
Owing to complaxity of geological conditions and limitation of explorating work before construction, revision and alteration of the design of construction details are normal things in construction stage. Alterable Geo-design includes the following ways. First, design before construction is prepared to fully alter. Then, new geological, deformation and failure informations and their engineering significance are fed back immediately. Last, according to these, the design is altered and revised with the assistance of CAD and returns to construction repidly. The authors take some real engineering examples to illustrate that feeding back and analysing these informations and ensuring normal flow of them are the key for optimum design. It is necessary to bring the design into design norm formally.
1993, 1(2): 79-84.
In this paper, firstly, the main characteristics of currently used analysis methods of rock slope stability are reviewed, which can be classified into two categories: a) The qualitative analysis methods, such as nature-history-geology analysis method, engineering geology analog method, graphic interpretation, expert system etc.; b) The quantitative analysis methods including: a. deterministic model methods, such as limiting equilirium method, stress-strain analysis method; b. Undeterministic model method, such as reliability analysis method, gray system theory method and fuzzy-synthetic evaluation; and c. rendom finite element method which is the combination of deterministic and undeterministic methods. Secondly, the design and stability analysis ofprestressing anchored rock slope are elaborated.
In this paper, firstly, the main characteristics of currently used analysis methods of rock slope stability are reviewed, which can be classified into two categories: a) The qualitative analysis methods, such as nature-history-geology analysis method, engineering geology analog method, graphic interpretation, expert system etc.; b) The quantitative analysis methods including: a. deterministic model methods, such as limiting equilirium method, stress-strain analysis method; b. Undeterministic model method, such as reliability analysis method, gray system theory method and fuzzy-synthetic evaluation; and c. rendom finite element method which is the combination of deterministic and undeterministic methods. Secondly, the design and stability analysis ofprestressing anchored rock slope are elaborated.
1993, 1(2): 85-92.
In the clay soil more or less amorphous free ferric oxide is present. Properties of clay soil are effected by the amorphous free ferric oxide and its crystals. In general the amorphous free ferric oxide effects the physical, hydrographical and engineering geological properites of clay soil. In this paper, the variation in properties of clay soil is studied by experiment in the process of dehydration. The authors hope this study is of benefit to geotechnical testing, geotechnical investigation and soil physics. The main results are as follows: (1) Liquid limit, plastic limit, and shrinkage limit in clay soil increase with increasing content of amorphous free ferric oxide, but in the process of dehydration of amorphous free ferric oxide this strengthening action decays. (2) In the clay soil amorphous free ferric oxide enhances its shrinkage. In case amorphous free ferric oxide was crystallized, the strengthening action decays or vanished, in this time strengthening action turned to restraint action on shrinkage. (3) In the process of dehydration, amorphous free ferric oxide forms structural connection, mechanical strength is enhenced by this connection in the clay soil, and the connection restrains expansion of clay soil.
In the clay soil more or less amorphous free ferric oxide is present. Properties of clay soil are effected by the amorphous free ferric oxide and its crystals. In general the amorphous free ferric oxide effects the physical, hydrographical and engineering geological properites of clay soil. In this paper, the variation in properties of clay soil is studied by experiment in the process of dehydration. The authors hope this study is of benefit to geotechnical testing, geotechnical investigation and soil physics. The main results are as follows: (1) Liquid limit, plastic limit, and shrinkage limit in clay soil increase with increasing content of amorphous free ferric oxide, but in the process of dehydration of amorphous free ferric oxide this strengthening action decays. (2) In the clay soil amorphous free ferric oxide enhances its shrinkage. In case amorphous free ferric oxide was crystallized, the strengthening action decays or vanished, in this time strengthening action turned to restraint action on shrinkage. (3) In the process of dehydration, amorphous free ferric oxide forms structural connection, mechanical strength is enhenced by this connection in the clay soil, and the connection restrains expansion of clay soil.
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