1997 Vol. 5, No. 2

论文
Nankun Railway runs from Nanning to Kunming through Yungui Plateau with total length of 863km,and height difference of 2000m. The geomorphic features differ along the line and bring a great difficulty in the project construction, many regions are connected by bridges and tunnels. The exposed rock layers, from Upper Proterzoic to Cenozoic deposits are located on the southwestern border of Yangtze paltform where folds are densely distributed, active faults longly, extend and seismic intensity reaches Ⅸ. The complication of regional geology and geological structure induces many geologic hazards, especially for the segment which runs 400km long through a carbonate rock region, where the karst is developed. These are found at the engineering foundations of bridges, tunnels and embankments. So, a large anount of engneeing design was taken. Furthermore embankment engineering was badly hindered by the long, highly expandable expansion rock. The way chosen and the effective measures taken for the complicated engineering geological conditions are discussed in this paper. Nankun Railway runs from Nanning to Kunming through Yungui Plateau with total length of 863km,and height difference of 2000m. The geomorphic features differ along the line and bring a great difficulty in the project construction, many regions are connected by bridges and tunnels. The exposed rock layers, from Upper Proterzoic to Cenozoic deposits are located on the southwestern border of Yangtze paltform where folds are densely distributed, active faults longly, extend and seismic intensity reaches Ⅸ. The complication of regional geology and geological structure induces many geologic hazards, especially for the segment which runs 400km long through a carbonate rock region, where the karst is developed. These are found at the engineering foundations of bridges, tunnels and embankments. So, a large anount of engneeing design was taken. Furthermore embankment engineering was badly hindered by the long, highly expandable expansion rock. The way chosen and the effective measures taken for the complicated engineering geological conditions are discussed in this paper.
Based on the site investigation of geology and analysis of observed deformation, it is shown in this paper that mining of T 3 3 coal beds in Mabukan slope over past hundred of years made upper rockmass tilt outward and subside. It is the direct reason why the rear edge of the slope top is tensiled and collapsed further. If there are no more activities of mining, along with the time going, the slope will be stable by itself. FEM (finite element method) calculation simulated and reproduced the relationship between the development process of tension and subsidence of the rear edge of slope top and mining. Based on the site investigation of geology and analysis of observed deformation, it is shown in this paper that mining of T 3 3 coal beds in Mabukan slope over past hundred of years made upper rockmass tilt outward and subside. It is the direct reason why the rear edge of the slope top is tensiled and collapsed further. If there are no more activities of mining, along with the time going, the slope will be stable by itself. FEM (finite element method) calculation simulated and reproduced the relationship between the development process of tension and subsidence of the rear edge of slope top and mining.
For solving the leakage problom from the tail of the lower reservoir of Ming Tombs Pumping-Storage Station, a cutoff needs to be constructed. Because there is an about 20 m thick alluvial clay layer in the river bed, the cutoff may be inserted into clay layer instead of bed rock, so that two third of the cost for cutoff will be saved. The paper discusses the continuity of the clay layer in the lower reservoir and a formation and distribution model of the clay layer is suggested according to the drilling result, geophysical and hydrogeological conditions. At last, it is pointed out that clay layer is widespread and continuous and it is feasible that cutoff is inserted into the clay layer. For solving the leakage problom from the tail of the lower reservoir of Ming Tombs Pumping-Storage Station, a cutoff needs to be constructed. Because there is an about 20 m thick alluvial clay layer in the river bed, the cutoff may be inserted into clay layer instead of bed rock, so that two third of the cost for cutoff will be saved. The paper discusses the continuity of the clay layer in the lower reservoir and a formation and distribution model of the clay layer is suggested according to the drilling result, geophysical and hydrogeological conditions. At last, it is pointed out that clay layer is widespread and continuous and it is feasible that cutoff is inserted into the clay layer.
In this paper, the method for fractal description of soil grains is improved and applied to describe the grain composition charateristic of interlayer shear zones. According to the fractal charalteristics, the grains from interlayer shear zones are classified into five types. Based on this result, their engineering geological indications are extensively and intensively discussed. A much attention is paid to amplitude of displacement and development stages of grains in the interlayer shear zones and their identifications by means of fractal character istics. And many aspects to be further discussed are also given. In this paper, the method for fractal description of soil grains is improved and applied to describe the grain composition charateristic of interlayer shear zones. According to the fractal charalteristics, the grains from interlayer shear zones are classified into five types. Based on this result, their engineering geological indications are extensively and intensively discussed. A much attention is paid to amplitude of displacement and development stages of grains in the interlayer shear zones and their identifications by means of fractal character istics. And many aspects to be further discussed are also given.
In this paper the holistic view in general and that of the Earth in particular are explained at first, then the guiding role of the latter in hydrogeological and engineering geological researches is elaborated separately at the levels of strategy, tactics, and battle, and the holistie view of hydrogeology and endineering geology is stated at the same levels. In this paper the holistic view in general and that of the Earth in particular are explained at first, then the guiding role of the latter in hydrogeological and engineering geological researches is elaborated separately at the levels of strategy, tactics, and battle, and the holistie view of hydrogeology and endineering geology is stated at the same levels.
Residual sliding displacements of rockmass usually occur on slopes by the effect of strong earthquakes. The displacement parameters are important for evaluating seismic stability of the slopes. In this paper the dynamic equilibrium equations for calculating sliding displacement of rockmass with layer and block structures on slopes are deduced, the corresponding calculation programs are compiled and the calculation results of an example are given. Residual sliding displacements of rockmass usually occur on slopes by the effect of strong earthquakes. The displacement parameters are important for evaluating seismic stability of the slopes. In this paper the dynamic equilibrium equations for calculating sliding displacement of rockmass with layer and block structures on slopes are deduced, the corresponding calculation programs are compiled and the calculation results of an example are given.
The factors for slope base rock vibration are analyzed in this paper, and a model is set up for single fault according to forced vibration of rock. The deformation law is described by using nonlinear dynamic equation, and causes for the slope movement are given while the rock is vibrating. It points out that the displacement could jump in a range of frequency and force amplitude, at the same time, the normal fault can open and the fault can stagger. The factors for slope base rock vibration are analyzed in this paper, and a model is set up for single fault according to forced vibration of rock. The deformation law is described by using nonlinear dynamic equation, and causes for the slope movement are given while the rock is vibrating. It points out that the displacement could jump in a range of frequency and force amplitude, at the same time, the normal fault can open and the fault can stagger.
Based on the sudden jump of deformation in unstable failure of rock under the soft loading condition, the deformation time curve of rock specimen was studied. The system composed of rock specimen and machine was studied by using a cusp catastrophic model. The result shows that the sudden jumps of deformation of rock specimens obtained by the two ways changed with the same trend. The deformation time and load time curves of rock specimens were measured by using HP 7090A Plot Measurement system under unstable condition. The experimental results are fairly in agreement with the theoretical consideration proposed and verified reliability of catastrophe theory in application to the study of rock. Based on the sudden jump of deformation in unstable failure of rock under the soft loading condition, the deformation time curve of rock specimen was studied. The system composed of rock specimen and machine was studied by using a cusp catastrophic model. The result shows that the sudden jumps of deformation of rock specimens obtained by the two ways changed with the same trend. The deformation time and load time curves of rock specimens were measured by using HP 7090A Plot Measurement system under unstable condition. The experimental results are fairly in agreement with the theoretical consideration proposed and verified reliability of catastrophe theory in application to the study of rock.
Probability characteristics of trace length are difficult to determine because of limited exposures. Methods presented by Kulatilake and Pahl can not estimate probability distribution function of trace length. So a new method is presented to estimate the mean as well as distribution function of trace length. This method does not need any data of trace length falling on the sampling window, which successfully lessens field work. The discontinuities falling on a sampling window are divided into four types, i.e. the penetrating type, intersecting types with one end above or below the window, and containing type. Dividing intersecting types into two categories can lessen the error induceed during survey. In terms of geometric probability, a new model is built. For one sampling window of certain orientation and size, the author derives a series of equations defining the relations between probabilities of each type and probability distribution function of trace length. In field work, it is easy to record the number of each discontinuity type on a window. So the frequencies of each type on the window can be calculated. For a certain mean and distribution function of trace length, the probability that one discontinuity belongs to each type can be calculated at the full integral areas of orientation and trace length. Then differences between probabilities and actual frequencies can be found. Four types of distribution function has been reported. So a trial and error method is applied to find the mean and distribution function with the lowest difference, which is assumed to be the actual ones. For engineering application, one program for estimating the mean and distribution function of trace length has been designed and was used in the analysis of discontinuity data in the Shiplock area of Three Gorges Project. Probability characteristics of trace length are difficult to determine because of limited exposures. Methods presented by Kulatilake and Pahl can not estimate probability distribution function of trace length. So a new method is presented to estimate the mean as well as distribution function of trace length. This method does not need any data of trace length falling on the sampling window, which successfully lessens field work. The discontinuities falling on a sampling window are divided into four types, i.e. the penetrating type, intersecting types with one end above or below the window, and containing type. Dividing intersecting types into two categories can lessen the error induceed during survey. In terms of geometric probability, a new model is built. For one sampling window of certain orientation and size, the author derives a series of equations defining the relations between probabilities of each type and probability distribution function of trace length. In field work, it is easy to record the number of each discontinuity type on a window. So the frequencies of each type on the window can be calculated. For a certain mean and distribution function of trace length, the probability that one discontinuity belongs to each type can be calculated at the full integral areas of orientation and trace length. Then differences between probabilities and actual frequencies can be found. Four types of distribution function has been reported. So a trial and error method is applied to find the mean and distribution function with the lowest difference, which is assumed to be the actual ones. For engineering application, one program for estimating the mean and distribution function of trace length has been designed and was used in the analysis of discontinuity data in the Shiplock area of Three Gorges Project.
Analysis of failure of patterns rock specimens in rock mechanics test enables us theoretically explain some mechanical phenomena often found in rock mechanics tests and give their reasonable answers. Meanwhile, the criteria for discriminating various models of rock failure were formulated. Then the theoretical and methodological discussions are made on the analysis of rock strength from rock-mechanical parameters interms of stress states. Analysis of failure of patterns rock specimens in rock mechanics test enables us theoretically explain some mechanical phenomena often found in rock mechanics tests and give their reasonable answers. Meanwhile, the criteria for discriminating various models of rock failure were formulated. Then the theoretical and methodological discussions are made on the analysis of rock strength from rock-mechanical parameters interms of stress states.
A correlative analysis is made between shear wave velocity and depth of some types of soil and rock in ShenZhen Region in this paper. The effect of geological origin, type, physical state of soil and rock and the geomorphic unit in which the site is located on shear wave velocity is considered during the analysis, and the important results which can direct geotechnical engineering are obtained. At last, a special discussion about mechanism of the relationship is made. A correlative analysis is made between shear wave velocity and depth of some types of soil and rock in ShenZhen Region in this paper. The effect of geological origin, type, physical state of soil and rock and the geomorphic unit in which the site is located on shear wave velocity is considered during the analysis, and the important results which can direct geotechnical engineering are obtained. At last, a special discussion about mechanism of the relationship is made.
Based on analysis and comprehensive assessment of present geophysical methods,a new method (TVSP) that is suitable for probing the geological conditions ahead of working face is suggested in this paper. Based on analysis and comprehensive assessment of present geophysical methods,a new method (TVSP) that is suitable for probing the geological conditions ahead of working face is suggested in this paper.
Geological hazards are the serious natural disasters that harm the living of mankind Its distribution, occurrence and process are of spatial character, and the influencing factors of them having their own features and complexity GHMIAS--The Geological Hazards Map and Image Analytical System is a kind of applied geological information system (GIS) Besides the basic functions of GIS, such as input, management,display, processing and output, etc, this newly developed system has fairly abundant GIS functions for analyzing and modeling as well as unique spatial analysis model extension The authors made out a lot of analysis on the hazards distribution, occurrence mechanism, influencing factors, development trend in Beijing Tianjin Tangshan area The spatial analysis of the subsidence process in urban district of Tianjin City reflects that the land subsidence in this place may still have a increasing trend in total The spatial prediction on the basis of gray theory shows that the mean spatial subsidence in study area will increase from 16 55 mm in 1990 to 19 38~19 77 mm in 1994, and probably will further increase to 22~24 mm in 1996. Geological hazards are the serious natural disasters that harm the living of mankind Its distribution, occurrence and process are of spatial character, and the influencing factors of them having their own features and complexity GHMIAS--The Geological Hazards Map and Image Analytical System is a kind of applied geological information system (GIS) Besides the basic functions of GIS, such as input, management,display, processing and output, etc, this newly developed system has fairly abundant GIS functions for analyzing and modeling as well as unique spatial analysis model extension The authors made out a lot of analysis on the hazards distribution, occurrence mechanism, influencing factors, development trend in Beijing Tianjin Tangshan area The spatial analysis of the subsidence process in urban district of Tianjin City reflects that the land subsidence in this place may still have a increasing trend in total The spatial prediction on the basis of gray theory shows that the mean spatial subsidence in study area will increase from 16 55 mm in 1990 to 19 38~19 77 mm in 1994, and probably will further increase to 22~24 mm in 1996.
In this paper, a theoretical analysis of elastic mechanics is used and the applied stress field and displacement field on prestressed anchor in wall rock are given. A general form of the formula for analyzing stress fielf in wall rock is shown. On this basis;the mechanical mechanism of prestressed anchor is expounded. In this paper, a theoretical analysis of elastic mechanics is used and the applied stress field and displacement field on prestressed anchor in wall rock are given. A general form of the formula for analyzing stress fielf in wall rock is shown. On this basis;the mechanical mechanism of prestressed anchor is expounded.
Jin Xiaoping
1997, 5(2): 188-192.
Abstract(2359)
627KB(15)