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Editor Work2001 Vol. 9, No. 1
Previous Issue
2001, 9(1): 3-11.
Abstract
156KB
Study of dynamics of the regional stability is to reveal the regularities of crustal dynamics, possible engineering hazard effects of the deformation and loss of stability of regional geological body. In this paper, the author systematically put forward a new theory of dynamics of regional stability, which includes basic geological background, the dynamics of regional surface stability, dynamics of regional shallow layer stability, dynamics of reional deep layer stability, dynamics of regional active tectonics, dynamics of regional seismicity, dynamic process and pattern of regional instability, seismic engineering effect in dynamic environment, effect of rock mass in stability, ect.
Study of dynamics of the regional stability is to reveal the regularities of crustal dynamics, possible engineering hazard effects of the deformation and loss of stability of regional geological body. In this paper, the author systematically put forward a new theory of dynamics of regional stability, which includes basic geological background, the dynamics of regional surface stability, dynamics of regional shallow layer stability, dynamics of reional deep layer stability, dynamics of regional active tectonics, dynamics of regional seismicity, dynamic process and pattern of regional instability, seismic engineering effect in dynamic environment, effect of rock mass in stability, ect.
2001, 9(1): 12-16.
The author defines a fundamental conception of regional stability dynamics and expounds its theory system and method system. Considering that region stability dynamics is a compound dynamics system with many sources, many layers,many subsystems, and many influencing elements, the author further suggests six fundamental principles for studying this compound dynamic system, they are principle of continuity, systematic principle, three dimensional principle , nonlinear principle , principle of dynamic state and engineering pragmatism principle.
The author defines a fundamental conception of regional stability dynamics and expounds its theory system and method system. Considering that region stability dynamics is a compound dynamics system with many sources, many layers,many subsystems, and many influencing elements, the author further suggests six fundamental principles for studying this compound dynamic system, they are principle of continuity, systematic principle, three dimensional principle , nonlinear principle , principle of dynamic state and engineering pragmatism principle.
The main characteristics of urban geologic map and its compilation principle and methods are discussed in following: (1)The significance of compiling urban geologic map is to meet the needs of urban construction and development, to make the geologic work better serve the overall plan and government decision making, and to provide basic data for practical engineering design and construction, and then to provide a scientific basis for rational development and use of urban land resource and conservation of urban geologic environment. (2)Urban geologic maps represents a series of maps, aiming at professional geologic planning, meeting, engineering geologic demand, and used for overall benefit evaluation. They are systematic maps with diverse functions that meet the demands of geologists , urban planners and designers as well as government policymakers, respectively. (3)Principles for compiling urban geologic map are:① objectivity; ② evaluation character ;③ Prediction character and ④ practicality. Objectivity, evaluation, and calculation are the precondition and basis, and practicality is the objective. Urban geologic map should be accurate, distinct, and readable. Its compilation must accord with the demands of city planning and government decision for geological technology. (4)Urban geological map includes three grades of maps with different functions, such as basic geologic map, and maps for analysis and evaluation and benefit decision evaluation. The compilation method and representation pattern must reflect the unification of grade contents nature use of maps, and the unification of technology, management, and policy decision.
The main characteristics of urban geologic map and its compilation principle and methods are discussed in following: (1)The significance of compiling urban geologic map is to meet the needs of urban construction and development, to make the geologic work better serve the overall plan and government decision making, and to provide basic data for practical engineering design and construction, and then to provide a scientific basis for rational development and use of urban land resource and conservation of urban geologic environment. (2)Urban geologic maps represents a series of maps, aiming at professional geologic planning, meeting, engineering geologic demand, and used for overall benefit evaluation. They are systematic maps with diverse functions that meet the demands of geologists , urban planners and designers as well as government policymakers, respectively. (3)Principles for compiling urban geologic map are:① objectivity; ② evaluation character ;③ Prediction character and ④ practicality. Objectivity, evaluation, and calculation are the precondition and basis, and practicality is the objective. Urban geologic map should be accurate, distinct, and readable. Its compilation must accord with the demands of city planning and government decision for geological technology. (4)Urban geological map includes three grades of maps with different functions, such as basic geologic map, and maps for analysis and evaluation and benefit decision evaluation. The compilation method and representation pattern must reflect the unification of grade contents nature use of maps, and the unification of technology, management, and policy decision.
2001, 9(1): 24-28.
Based on the characteristics of seepage in fracture network of rock mass, two forces the normal seepage pressure and the tangent force applied to the fracture walls are studied. The equivalent node forces of joint element are deduced under the two dimensional and three dimensional conditions. An example shows the effect of seepage in fracture network on the stress of rock mass. It comes to the conclusions that seepage forces in fracture network of rock mass decrease the compressive stress of rock mass above the fractures and increase the compressive stress of rock mass below the fractures (10.53%). The forces increase the tensile stress of rock mass (9.09%), and increase the shear stress of rock mass (23.75%).
Based on the characteristics of seepage in fracture network of rock mass, two forces the normal seepage pressure and the tangent force applied to the fracture walls are studied. The equivalent node forces of joint element are deduced under the two dimensional and three dimensional conditions. An example shows the effect of seepage in fracture network on the stress of rock mass. It comes to the conclusions that seepage forces in fracture network of rock mass decrease the compressive stress of rock mass above the fractures and increase the compressive stress of rock mass below the fractures (10.53%). The forces increase the tensile stress of rock mass (9.09%), and increase the shear stress of rock mass (23.75%).
2001, 9(1): 29-31.
It is very important to investigate the forces acting on the rock mass by the seepage flow in fracture network. The forces acting on the fissure walls by the seepage flow include the hydrostatic seepage pressure and the hauling force. Based on the cubic law of the single fissure flow, the equation of the hauling force with which the single fissure flow acts on the fissure walls is deduced by means of the momentum law of fluid mechanics. The equation is compared with the hydrodynamic pressure theory of continuum seepage. The result in the paper is a foundation for couple mechanism analysis of flow and stress in fractured rock mass.
It is very important to investigate the forces acting on the rock mass by the seepage flow in fracture network. The forces acting on the fissure walls by the seepage flow include the hydrostatic seepage pressure and the hauling force. Based on the cubic law of the single fissure flow, the equation of the hauling force with which the single fissure flow acts on the fissure walls is deduced by means of the momentum law of fluid mechanics. The equation is compared with the hydrodynamic pressure theory of continuum seepage. The result in the paper is a foundation for couple mechanism analysis of flow and stress in fractured rock mass.
2001, 9(1): 32-38.
The principle and calculation method of dynamic discrete element are proposed in the paper. They were used in analyzing the stability and dynamic response of a typical landslide to strong earthquake. It is suggested that dynamic analysis of slope in seismic area is necessary.
The principle and calculation method of dynamic discrete element are proposed in the paper. They were used in analyzing the stability and dynamic response of a typical landslide to strong earthquake. It is suggested that dynamic analysis of slope in seismic area is necessary.
2001, 9(1): 39-43.
The formation and movement of Xian ground fissures are mainly caused by geotectonic movement and human activities. The extraording movement of the ground fissures mainly resulted from uneven ground subsidence that caused by the over pumping of ground water. According to analyses of compaction consolidation process of sediments layers, ground water variation tendency, and result of Verhulst model prediction, it is concluded that the movement intensity of Xian ground fissures tends to gradually become weaken. The resent observation data on ground fissures movement show some indicatons to reduction in its rate.
The formation and movement of Xian ground fissures are mainly caused by geotectonic movement and human activities. The extraording movement of the ground fissures mainly resulted from uneven ground subsidence that caused by the over pumping of ground water. According to analyses of compaction consolidation process of sediments layers, ground water variation tendency, and result of Verhulst model prediction, it is concluded that the movement intensity of Xian ground fissures tends to gradually become weaken. The resent observation data on ground fissures movement show some indicatons to reduction in its rate.
2001, 9(1): 44-50.
The reinforcement is a stepped R.C. series connection slab constructing a reinforced earth retaining wall. The author analyses stress of the reinforcement, earth pressure on the retaining wall, vertical pressure of backfilled soil, and deformation of slip plane for backfill behind wall. The results can be used as reference for similar retaining structure.
The reinforcement is a stepped R.C. series connection slab constructing a reinforced earth retaining wall. The author analyses stress of the reinforcement, earth pressure on the retaining wall, vertical pressure of backfilled soil, and deformation of slip plane for backfill behind wall. The results can be used as reference for similar retaining structure.
2001, 9(1): 51-56.
By analyzing the relation between construction design and investment budget estimate in preliminary design stage of a landslide hazard protection engineering project, it is concluded that the effect of construction design on investment budget estimate is larger than that of engineering design and geological exploration. It is pointed out that the consturction procedure design plays an important role in increasing reliability of budget estimate.
By analyzing the relation between construction design and investment budget estimate in preliminary design stage of a landslide hazard protection engineering project, it is concluded that the effect of construction design on investment budget estimate is larger than that of engineering design and geological exploration. It is pointed out that the consturction procedure design plays an important role in increasing reliability of budget estimate.
2001, 9(1): 57-61.
On the basis of analysis of the movement characteristics of horizontal layered foundation and the relationship between soil parameters and eigenvalues and eigenvectors of the soil system, frequency domain identification method of the layered foundation parameters is suggested by correcting the deviation between the measured soil data and theoretical calculation results.In addition, the frequency identification process of the layered foundation parameters is performed by using the data from foundation model experiment. The result shows that the method can yields good estimate of the layer foundation parameters.
On the basis of analysis of the movement characteristics of horizontal layered foundation and the relationship between soil parameters and eigenvalues and eigenvectors of the soil system, frequency domain identification method of the layered foundation parameters is suggested by correcting the deviation between the measured soil data and theoretical calculation results.In addition, the frequency identification process of the layered foundation parameters is performed by using the data from foundation model experiment. The result shows that the method can yields good estimate of the layer foundation parameters.
2001, 9(1): 62-67.
The major sources for uncertaing of physical and mechanical indexes of loess are discussed in the paper. The main indexes of the typical loess are statistically analysed. The result shows that there is regional distinction in average value standard deviation, and variation coefficient of the characteristic indexes, and therefore, statistics of the indexes should be aimed at specific project. The distribution of the main indexes of loess is almost normal distribution. When the loess slope stability is calculated, the distribution of loess indexes can be approximate from by the normal distribution.
The major sources for uncertaing of physical and mechanical indexes of loess are discussed in the paper. The main indexes of the typical loess are statistically analysed. The result shows that there is regional distinction in average value standard deviation, and variation coefficient of the characteristic indexes, and therefore, statistics of the indexes should be aimed at specific project. The distribution of the main indexes of loess is almost normal distribution. When the loess slope stability is calculated, the distribution of loess indexes can be approximate from by the normal distribution.
2001, 9(1): 68-73.
The random seismic response analysis method of soil in site when its shear modulus changes linearly with the depth is studied and the random seismic response analysis theory of soil in site when seismic acceleration power spectrum of bedrock input are white noise and filter white noise is proposed.
The random seismic response analysis method of soil in site when its shear modulus changes linearly with the depth is studied and the random seismic response analysis theory of soil in site when seismic acceleration power spectrum of bedrock input are white noise and filter white noise is proposed.
2001, 9(1): 74-80.
The mechanism of set out violent slide of slope mass during earthquake is discussed in the paper. The authors study suggests that there are three effects of the slope mass vibration in its deformation and failure process during earthquake. They are progressive failure, set out slide, and acceleration effects. By using discrete element method, the processal of deformation and failure of Luotuoling landslide is simulated. The obtained result is of theoretecal and practical signifiance.
The mechanism of set out violent slide of slope mass during earthquake is discussed in the paper. The authors study suggests that there are three effects of the slope mass vibration in its deformation and failure process during earthquake. They are progressive failure, set out slide, and acceleration effects. By using discrete element method, the processal of deformation and failure of Luotuoling landslide is simulated. The obtained result is of theoretecal and practical signifiance.
2001, 9(1): 81-86.
The authors used radon survey method,measured the radon content on main faults and their activity in Northern Qinling belt, firstly put forward the relative standards for discriminaling randon survey result in relation with fault activity in the belt, interpreted and analyzed the typical randon survey profiles in the belt, discriminated the relative fault activity and activity levels and related problems,and then briefly discussed the effect of the faults on future sustainable development model and framework in Northern Qinling belt.
The authors used radon survey method,measured the radon content on main faults and their activity in Northern Qinling belt, firstly put forward the relative standards for discriminaling randon survey result in relation with fault activity in the belt, interpreted and analyzed the typical randon survey profiles in the belt, discriminated the relative fault activity and activity levels and related problems,and then briefly discussed the effect of the faults on future sustainable development model and framework in Northern Qinling belt.
2001, 9(1): 93-99.
通过不同土性、地下水条件下软土基坑开挖变形失稳的模拟试验, 研究了软土基坑开挖变形发展直至失稳破坏的全过程。通过试验研究, 初步认为软土基坑坑壁在无支护或支护刚度较小的情况下, 其坑壁破坏形态呈抛物线型; 在基坑开挖范围内若存在有砂性土, 且地下水位较高时, 易于发生流砂渗透破坏, 并导致了地表沉陷, 但侧向变形相对较小; 而对于因承压水引起的坑底土体隆起变形, 若不考虑土体的强度特性, 计算结果是偏于安全的。
通过不同土性、地下水条件下软土基坑开挖变形失稳的模拟试验, 研究了软土基坑开挖变形发展直至失稳破坏的全过程。通过试验研究, 初步认为软土基坑坑壁在无支护或支护刚度较小的情况下, 其坑壁破坏形态呈抛物线型; 在基坑开挖范围内若存在有砂性土, 且地下水位较高时, 易于发生流砂渗透破坏, 并导致了地表沉陷, 但侧向变形相对较小; 而对于因承压水引起的坑底土体隆起变形, 若不考虑土体的强度特性, 计算结果是偏于安全的。
2001, 9(1): 87-92.
Based on the in situ test of pile soil interaction of filling pile, combining with the properties of soils in Xian, and modelings pile soil interaction of concrete filling pile in the loess area by using finite element method, the authors studied pile soil interaction, regularity of load transferring, and the relation between relative displacement and lateral friction resistance of the pile. By comparing of pile load test data,it is found that the modeling result by three dimensional finite element method is similar to that of actual measurement. Moreover, the essence of pile soil interaction is revealed. It provides a basis for the selection of optimum pile length and the definition of pile bearing capacity.
Based on the in situ test of pile soil interaction of filling pile, combining with the properties of soils in Xian, and modelings pile soil interaction of concrete filling pile in the loess area by using finite element method, the authors studied pile soil interaction, regularity of load transferring, and the relation between relative displacement and lateral friction resistance of the pile. By comparing of pile load test data,it is found that the modeling result by three dimensional finite element method is similar to that of actual measurement. Moreover, the essence of pile soil interaction is revealed. It provides a basis for the selection of optimum pile length and the definition of pile bearing capacity.
2001, 9(1): 100-106.
?sp? Hard Rock Laboratoty is a planned permanent repository for nuclear waste in Sweden. In situ stress measurement result indicates that both magnitude and orientation of stress vary greatly. It is thought that these variations are related to the development of fractures. Using diserete element method and UDEC code, the autors simulated the stress field in Aspo area. The simulation considered both plane model and vertical model. The results show that both magnitude and orientation of stress change in the vicinity of fractured zones and coincide well with the measured result. Principal stress reorientes near fractured zone and the reoriented angle depends on the angle between fractured zone and the direction of boundary stress. For the vertical model, the result from lower angle model is similar to the measured result. An approach to determining normal stiffness and shear stiffness of fracture zone is also discussed in the paper.
?sp? Hard Rock Laboratoty is a planned permanent repository for nuclear waste in Sweden. In situ stress measurement result indicates that both magnitude and orientation of stress vary greatly. It is thought that these variations are related to the development of fractures. Using diserete element method and UDEC code, the autors simulated the stress field in Aspo area. The simulation considered both plane model and vertical model. The results show that both magnitude and orientation of stress change in the vicinity of fractured zones and coincide well with the measured result. Principal stress reorientes near fractured zone and the reoriented angle depends on the angle between fractured zone and the direction of boundary stress. For the vertical model, the result from lower angle model is similar to the measured result. An approach to determining normal stiffness and shear stiffness of fracture zone is also discussed in the paper.
2001, 9(1): 107-112.
The deformed rock mass at the right abutment of the Heihe Reservoir of Xian City was formed by rotation. Thus, the analysis of its stability must be performed by three dimension method. However, current calculation methods are difficult to be put into practical use due to their complicity. This paper writes a 3-D program of the rigid limited-equilibrium method by which both the stability coefficient and the pushing force of landslide can be computed. Then, it is applied to the stability analysis of deformed rock mass at the right abutment of Heihe Reservoir. The result correlates well with real case and provide evidence for the engineering prevention.
The deformed rock mass at the right abutment of the Heihe Reservoir of Xian City was formed by rotation. Thus, the analysis of its stability must be performed by three dimension method. However, current calculation methods are difficult to be put into practical use due to their complicity. This paper writes a 3-D program of the rigid limited-equilibrium method by which both the stability coefficient and the pushing force of landslide can be computed. Then, it is applied to the stability analysis of deformed rock mass at the right abutment of Heihe Reservoir. The result correlates well with real case and provide evidence for the engineering prevention.
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