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Editor Work1999 Vol. 7, No. 2
Previous Issue
1999, 7(2): 99-104.
Abstract
294KB
The Ming Tombs Pumping Storage Power Station is a large scale hydropower projec t with an underground power house. Locating the power house is one of the mos t important problems for the project not only in the conditions for construction but also in economic cost. The paper analyses firstly the characteristics of f aults and fractures which control the location of the power house in the area. Secondly, the surrounding rocks of the power house is classified from some phys ical and mechanical indexes. Meanwhile, the stability of surrounding rocks of th e power house is analyzed and the different geological conditions are evaluated . Finally, the engineering geological conditions considered in three plans for locating the power house are compared. It follows that the plan Ⅲ is the best one.
The Ming Tombs Pumping Storage Power Station is a large scale hydropower projec t with an underground power house. Locating the power house is one of the mos t important problems for the project not only in the conditions for construction but also in economic cost. The paper analyses firstly the characteristics of f aults and fractures which control the location of the power house in the area. Secondly, the surrounding rocks of the power house is classified from some phys ical and mechanical indexes. Meanwhile, the stability of surrounding rocks of th e power house is analyzed and the different geological conditions are evaluated . Finally, the engineering geological conditions considered in three plans for locating the power house are compared. It follows that the plan Ⅲ is the best one.
1999, 7(2): 105-111.
The basic quality of rock mass at the dam foundation of Geheyan hydropower pro ject is determined by using qualitative and quantitative methods assighed in Criteria for Classification of Engineering Rock Mass and according to the roc k hardness and intact degree. Then a quality classification of the rock mass at the dam foudation is made on the basis of groundwater, ground stress,and the si tuation of soft and weaken structural planes, and the modified assessment resu lts of the rock mass quality. Considering the engineering practice, such as inte rlayer shear plane, karst situation,etc,the assessment result of engineering roc k mass system at the dam site is obtained.
The basic quality of rock mass at the dam foundation of Geheyan hydropower pro ject is determined by using qualitative and quantitative methods assighed in Criteria for Classification of Engineering Rock Mass and according to the roc k hardness and intact degree. Then a quality classification of the rock mass at the dam foudation is made on the basis of groundwater, ground stress,and the si tuation of soft and weaken structural planes, and the modified assessment resu lts of the rock mass quality. Considering the engineering practice, such as inte rlayer shear plane, karst situation,etc,the assessment result of engineering roc k mass system at the dam site is obtained.
1999, 7(2): 112-117.
The concept of the 3S analysis system and its application to the slope s tability analysis in the Three Gorges area are introduced in the paper. The con tents and basic frame of the 3S engineering analysis system of the slope stabil ity in the Three Gorges area are also expounded. It is expected that the design and the perfection of this system have important social significance and its b road future application.
The concept of the 3S analysis system and its application to the slope s tability analysis in the Three Gorges area are introduced in the paper. The con tents and basic frame of the 3S engineering analysis system of the slope stabil ity in the Three Gorges area are also expounded. It is expected that the design and the perfection of this system have important social significance and its b road future application.
1999, 7(2): 118-124.
Urban subaqueous highway tunnel,not only subaqueous,but also in u rban area,is a typical geotechnical engineering in vulnerable envir onment.Based on the analysis of the adverse geological conditions and urban envi ronment restraint factors, in this paper we analyse the environmental impact of the construction, and then preliminarily evaluate the site and construction sche me of Xuanwu Lake subaqueous highway tunnel.
Urban subaqueous highway tunnel,not only subaqueous,but also in u rban area,is a typical geotechnical engineering in vulnerable envir onment.Based on the analysis of the adverse geological conditions and urban envi ronment restraint factors, in this paper we analyse the environmental impact of the construction, and then preliminarily evaluate the site and construction sche me of Xuanwu Lake subaqueous highway tunnel.
1999, 7(2): 125-134.
Chemical weathering of igneous rocks is principally a process of hydrolysi s, leaching loss of alkali and alkali earth metals, removal of silica and accu mulation of aluminum oxides. Rocks with different weathering degrees should po ssess distinctive chemical compositions,which thus can be used to develop variou s weathering indices. After studying 150 samples from various depths at two site sin Hong Kong, a set of chemical weathering indices is proposed to classify the weathered granitic rocks with different weathering degrees in Hong Kong. The pro posed chemical classification system provides not only a theoretical basis for i nvestigating the influence of weathering on engineering properties of weathered rocks, but also a scientific and reliable approach to classify the rocks with d ifferent degrees of weathering.
Chemical weathering of igneous rocks is principally a process of hydrolysi s, leaching loss of alkali and alkali earth metals, removal of silica and accu mulation of aluminum oxides. Rocks with different weathering degrees should po ssess distinctive chemical compositions,which thus can be used to develop variou s weathering indices. After studying 150 samples from various depths at two site sin Hong Kong, a set of chemical weathering indices is proposed to classify the weathered granitic rocks with different weathering degrees in Hong Kong. The pro posed chemical classification system provides not only a theoretical basis for i nvestigating the influence of weathering on engineering properties of weathered rocks, but also a scientific and reliable approach to classify the rocks with d ifferent degrees of weathering.
1999, 7(2): 135-140.
Based on the theory of geological control and rock hydromechanics, this pape r insists that the geotexture governs fluid flow in rock masses most directly. T he geotexture is graded properly with consideration on the characteristics of fl uid flow in rocks. Four important effects of geotexture on fluid flow are propos ed, i.e., the graded preference effect, the channeling intersection effect, the unsaturation effect and the coupling effect. The basic meaning, relationships an d engineering significance of these four effects are preliminarily discussed.
Based on the theory of geological control and rock hydromechanics, this pape r insists that the geotexture governs fluid flow in rock masses most directly. T he geotexture is graded properly with consideration on the characteristics of fl uid flow in rocks. Four important effects of geotexture on fluid flow are propos ed, i.e., the graded preference effect, the channeling intersection effect, the unsaturation effect and the coupling effect. The basic meaning, relationships an d engineering significance of these four effects are preliminarily discussed.
1999, 7(2): 141-146.
By studying the deformation failure characteristic of down dip slopes in the front and rear of a dam for Lijiaxia Hydropower Station,here we suggest a c lassification of the deformation and failure types of down dip slopes and anly sise the critical conditions for rotating slide and failure of the slopes.
By studying the deformation failure characteristic of down dip slopes in the front and rear of a dam for Lijiaxia Hydropower Station,here we suggest a c lassification of the deformation and failure types of down dip slopes and anly sise the critical conditions for rotating slide and failure of the slopes.
1999, 7(2): 147-153.
On November 4～5,1993, Lantau Island with an area of 120 km2 which is the larg est outlying island of Hong Kong Territory experienced an extremely severe loca lized rainstorm, which resulted in over 800 soil slide debris flows on the natu ral terrain there. The majority of the soil slides debris flows occurred in are a with volcanic rock derived residual soil and colluvium. Triaxial tests, incl uding compression tests anisotropically consolidated undrained and drained, und isturbed volcanic rock derived soil specimens at constant shear stress, were pe rformed to investigate the stress strain behaviors of the soil. The test result s are interpreted to suggest that soil slide debris flow initiation occurs as a two stage process which consists of an initial dilation failure under drain co nditions followed by undrained failure as a result of strain softening.
On November 4～5,1993, Lantau Island with an area of 120 km2 which is the larg est outlying island of Hong Kong Territory experienced an extremely severe loca lized rainstorm, which resulted in over 800 soil slide debris flows on the natu ral terrain there. The majority of the soil slides debris flows occurred in are a with volcanic rock derived residual soil and colluvium. Triaxial tests, incl uding compression tests anisotropically consolidated undrained and drained, und isturbed volcanic rock derived soil specimens at constant shear stress, were pe rformed to investigate the stress strain behaviors of the soil. The test result s are interpreted to suggest that soil slide debris flow initiation occurs as a two stage process which consists of an initial dilation failure under drain co nditions followed by undrained failure as a result of strain softening.
1999, 7(2): 154-160.
Seam sliding zones are commonly found in faulted depression basins in Nor th China and become the important factors influencing the stability of their s urrounding rockmass in underground miningworkings. Taking mining areas in weste rn Shandong as examples, this paper discusses development characteristics of sea m sliding zone and its formation mechanism, analyses its repeated deformation u nder the conditions of excavation and operation, and points out some problems to which should be paid attention during roadway designing and maintaining near th e seam sliding zone.
Seam sliding zones are commonly found in faulted depression basins in Nor th China and become the important factors influencing the stability of their s urrounding rockmass in underground miningworkings. Taking mining areas in weste rn Shandong as examples, this paper discusses development characteristics of sea m sliding zone and its formation mechanism, analyses its repeated deformation u nder the conditions of excavation and operation, and points out some problems to which should be paid attention during roadway designing and maintaining near th e seam sliding zone.
1999, 7(2): 161-167.
The soil microstructure is a kind of states of substance, which cou ld be described with a conceptual model possessing tree structure. Based on ima ge processing technology, a technical way to quantify the microstructure and a method to determine the indefinite structural factors are put forwards. By analysis of fractal geometry, the influence of natural structure and pressure on the subsidence of loess and the regularities of reaction between water an d soil have been studied. And then the mechanism for control on the subsidence due to fractal structure is suggested.
The soil microstructure is a kind of states of substance, which cou ld be described with a conceptual model possessing tree structure. Based on ima ge processing technology, a technical way to quantify the microstructure and a method to determine the indefinite structural factors are put forwards. By analysis of fractal geometry, the influence of natural structure and pressure on the subsidence of loess and the regularities of reaction between water an d soil have been studied. And then the mechanism for control on the subsidence due to fractal structure is suggested.
1999, 7(2): 168-174.
Loess landslides, especially those induced by earthquakes,are always the one kind of outstanding geologic hazards in the vast loess areas of West China . According to the basic idea and principle of genetic algorithm, a new metho d for determining the most risk slip surface of a loess slope is established. The test results show that the method is more effective and practical in the stability analysis of a loess landslide than traditional methods.
Loess landslides, especially those induced by earthquakes,are always the one kind of outstanding geologic hazards in the vast loess areas of West China . According to the basic idea and principle of genetic algorithm, a new metho d for determining the most risk slip surface of a loess slope is established. The test results show that the method is more effective and practical in the stability analysis of a loess landslide than traditional methods.
1999, 7(2): 175-180.
An elastic wave technique is used to measure the properties of coral reef rock of core Nanyong 1 and other coral reef samples From the result the relation of wave velocity with depth is determined General trend of longitudinal wave velo city is studied from the development history,sedimentology, petrology,sedimentar y cycles and palaeomagnetic chronology The relation of longitudinal wave veloci ty with ages, texture and types of rocks, porosity, sedimentary environment of c oral reef rock, and geological events is analysed. It shows that anomalous value s of longitudinal wave velocity are the consequence of integrated effect of the se geological factors. The study of elastic wave properties is of important sig nificance in coral reef geology and can be used in the structural and stability analysis of coral reef.
An elastic wave technique is used to measure the properties of coral reef rock of core Nanyong 1 and other coral reef samples From the result the relation of wave velocity with depth is determined General trend of longitudinal wave velo city is studied from the development history,sedimentology, petrology,sedimentar y cycles and palaeomagnetic chronology The relation of longitudinal wave veloci ty with ages, texture and types of rocks, porosity, sedimentary environment of c oral reef rock, and geological events is analysed. It shows that anomalous value s of longitudinal wave velocity are the consequence of integrated effect of the se geological factors. The study of elastic wave properties is of important sig nificance in coral reef geology and can be used in the structural and stability analysis of coral reef.
1999, 7(2): 181-186.
A typical trigonometric polynimical function model graph is constructed for clas sification and identification engineering rock mass structures. The typical mode l graphs for identification of engineering rock mass structures at dam foundatio n are presented for study of Changjiang Three Gorges project and Qingjiang Gaob azhou Hydropower project. The method of trigonometric polonomial function model is of practical significance for quantitative classification of engineering rock mass structures.
A typical trigonometric polynimical function model graph is constructed for clas sification and identification engineering rock mass structures. The typical mode l graphs for identification of engineering rock mass structures at dam foundatio n are presented for study of Changjiang Three Gorges project and Qingjiang Gaob azhou Hydropower project. The method of trigonometric polonomial function model is of practical significance for quantitative classification of engineering rock mass structures.
1999, 7(2): 187-192.
It is important to choose a FLAC model and use FLAC program to simulate stati c probe cone load test. In this paper the static cone load test is designed a s an axisymmetric geometry, and two different models are bulit, one is the model with the cone, and another is the model without cone. The simulation results on the two models are approximate. In general, the simplified fast running mode l without cone can meet the needs of tests.
It is important to choose a FLAC model and use FLAC program to simulate stati c probe cone load test. In this paper the static cone load test is designed a s an axisymmetric geometry, and two different models are bulit, one is the model with the cone, and another is the model without cone. The simulation results on the two models are approximate. In general, the simplified fast running mode l without cone can meet the needs of tests.
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