Weak rock zone (soft interlayer, fault zone and soft rock) is the highlight of large-scale geological engineering research. It is an important boundary for analysis of rock mass stability. Weak rock zone has been form...Weak rock zone (soft interlayer, fault zone and soft rock) is the highlight of large-scale geological engineering research. It is an important boundary for analysis of rock mass stability. Weak rock zone has been formed in a long geological period, and in this period, various rocks have undergone long-term consolidation of geostatic stress and tectonic stress; therefore, under in-situ conditions, their density and modulus of deformation are relatively high. Due to its fragmentary nature, once being exposed to the earth's surface, the structure of weak rock zone will soon be loosened, its density will be reduced, and its modulus of deformation will also be reduced significantly. Generally, weak rock zone can be found in large construction projects, especially in the dam foundation rocks of hydropower stations. These rocks cannot be eliminated completely by excavation. Furthermore, all tests nowadays are carried out after the exposure of weak rock zone, modulus of deformation under in-situ conditions cannot be revealed. In this paper, a test method explored by the authors has been introduced. This method is a whole multilayered medium deformation method. It is unnecessary to eliminate the relatively complete rocks covering on weak rock zone. A theoretical formula to obtain the modulus of deformation in various mediums has also been introduced. On-site comparative trials and indoor deformation modulus tests under equivalent density conditions have been carried out. We adopted several methods for the prediction researches of the deformation modulus of weak rock zone under in-situ conditions, and revealed a fact that under in-situ conditions, the deformation modulus of weak rock zone are several times higher than the test results obtained after the exposure. In a perspective of geological engineering, the research findings have fundamentally changed peoples' concepts on the deformation modulus of weak rock zone, provided important theories and methods for precise definition of deformation modulus of deep weak rock zone under cap rock conditions, as well as for reasonable engineering applications.展开更多
This paper proposes the environmental burden and benefit assessment method, which contributes to the evaluation of public works, by considering a quantitative environmental impact. The method developed is applied for ...This paper proposes the environmental burden and benefit assessment method, which contributes to the evaluation of public works, by considering a quantitative environmental impact. The method developed is applied for the Bangkok subway construction project, so that the environmental impact following the Bangkok subway construction work is evaluated on the basis of environmental accounting. As a result, it was possible to quantify the burden and benefits to the environment in the life cycle of the Bangkok subway. In addition by converting the burden and benefits of the Bangkok subway construction project into monetary terms and introducing the Economic Internal Rate of Return (EIRR), it was possible to evaluate the subway construction project from an economic point of view.展开更多
Soils with strain-softening behavior — manifesting as a reduction of strength with increasing plastic strain — are commonly found in the natural environment. For slopes in these soils,a progressive failure mechanism...Soils with strain-softening behavior — manifesting as a reduction of strength with increasing plastic strain — are commonly found in the natural environment. For slopes in these soils,a progressive failure mechanism can occur due to a reduction of strength with increasing strain. Finite element method based numerical approaches have been widely performed for simulating such failure mechanism,owning to their ability for tracing the formation and development of the localized shear strain. However,the reliability of the currently used approaches are often affected by poor convergence or significant mesh-dependency,and their applicability is limited by the use of complicated soil models. This paper aims to overcome these limitations by developing a finite element approach using a local arc-length controlled iterative algorithm as the solution strategy. In the proposed finite element approach,the soils are simulated with an elastoplastic constitutive model in conjunction with the Mohr-Coulomb yield function. The strain-softening behavior is represented by a piece-wise linearrelationship between the Mohr-Coulomb strength parameters and the deviatoric plastic strain. To assess the reliability of the proposed finite element approach,comparisons of the numerical solutions obtained by different finite element methods and meshes with various qualities are presented. Moreover,a landslide triggered by excavation in a real expressway construction project is analyzed by the presented finite element approach to demonstrate its applicability for practical engineering problems.展开更多
After a long period without new NPPs (nuclear power plants) being designed or constructed in Europe, new build projects have been prepared, planned and are now under construction. The majority of these projects invo...After a long period without new NPPs (nuclear power plants) being designed or constructed in Europe, new build projects have been prepared, planned and are now under construction. The majority of these projects involve a new design with an enhanced level of safety, called GEN (Generation) III+. Although the serious events at the Japanese Fukushima Daiichi NPP caused by a tsunami led to a reduction in the number of new projects or even a phase out of nuclear power in some countries, only a slight reduction or delay of projects is expected globally. GEN III+ new build projects give rise to several economical, technical, human resource and organizational challenges. The paper starts with a discussion of these challenges and presents several activities that have been started to deal with them. It focuses on the development of human resources, coordinated approach of operators and suppliers can lead to the needs-oriented human resources development. particularly with operators and suppliers of GEN III+ NPPs. Only a successful execution of these projects. The focus must be on the展开更多
The principal means of conserving water and utilizing hydropower in China is to exploit the use of a series of reservoirs in a cascade. This method and its inherent engineering safety problems are receiving increasing...The principal means of conserving water and utilizing hydropower in China is to exploit the use of a series of reservoirs in a cascade. This method and its inherent engineering safety problems are receiving increasing attention nowadays. In the field of engineering safety analysis, much work has focused on single reservoir projects in the past few years, but there is little research available on the safety risk analysis of cascade reservoirs, either within China or internationally. Therefore, a framework for risk analysis on the cascade reservoir system based on the theory of system engineering is constructed in this article. A cascading failure model is established and the connection degree factor discussed. In addition, the importance degree of the subsystem, which can be calculated by combining the analytical hierarchy process and the entropy weight method, is explained. According to brittleness theory of a complex system, brittle risk entropy is proposed as a performance index for measuring the collapse uncertainty of the cascade reservoir system. In addition, the brittle risk of the cascade reservoir system is predicted, which provides a reference for safety analysis in water conservation and hydropower construction projects in China.展开更多
文摘Weak rock zone (soft interlayer, fault zone and soft rock) is the highlight of large-scale geological engineering research. It is an important boundary for analysis of rock mass stability. Weak rock zone has been formed in a long geological period, and in this period, various rocks have undergone long-term consolidation of geostatic stress and tectonic stress; therefore, under in-situ conditions, their density and modulus of deformation are relatively high. Due to its fragmentary nature, once being exposed to the earth's surface, the structure of weak rock zone will soon be loosened, its density will be reduced, and its modulus of deformation will also be reduced significantly. Generally, weak rock zone can be found in large construction projects, especially in the dam foundation rocks of hydropower stations. These rocks cannot be eliminated completely by excavation. Furthermore, all tests nowadays are carried out after the exposure of weak rock zone, modulus of deformation under in-situ conditions cannot be revealed. In this paper, a test method explored by the authors has been introduced. This method is a whole multilayered medium deformation method. It is unnecessary to eliminate the relatively complete rocks covering on weak rock zone. A theoretical formula to obtain the modulus of deformation in various mediums has also been introduced. On-site comparative trials and indoor deformation modulus tests under equivalent density conditions have been carried out. We adopted several methods for the prediction researches of the deformation modulus of weak rock zone under in-situ conditions, and revealed a fact that under in-situ conditions, the deformation modulus of weak rock zone are several times higher than the test results obtained after the exposure. In a perspective of geological engineering, the research findings have fundamentally changed peoples' concepts on the deformation modulus of weak rock zone, provided important theories and methods for precise definition of deformation modulus of deep weak rock zone under cap rock conditions, as well as for reasonable engineering applications.
文摘This paper proposes the environmental burden and benefit assessment method, which contributes to the evaluation of public works, by considering a quantitative environmental impact. The method developed is applied for the Bangkok subway construction project, so that the environmental impact following the Bangkok subway construction work is evaluated on the basis of environmental accounting. As a result, it was possible to quantify the burden and benefits to the environment in the life cycle of the Bangkok subway. In addition by converting the burden and benefits of the Bangkok subway construction project into monetary terms and introducing the Economic Internal Rate of Return (EIRR), it was possible to evaluate the subway construction project from an economic point of view.
基金funded by the Chinese National Basic Research Program (2010CB731503)
文摘Soils with strain-softening behavior — manifesting as a reduction of strength with increasing plastic strain — are commonly found in the natural environment. For slopes in these soils,a progressive failure mechanism can occur due to a reduction of strength with increasing strain. Finite element method based numerical approaches have been widely performed for simulating such failure mechanism,owning to their ability for tracing the formation and development of the localized shear strain. However,the reliability of the currently used approaches are often affected by poor convergence or significant mesh-dependency,and their applicability is limited by the use of complicated soil models. This paper aims to overcome these limitations by developing a finite element approach using a local arc-length controlled iterative algorithm as the solution strategy. In the proposed finite element approach,the soils are simulated with an elastoplastic constitutive model in conjunction with the Mohr-Coulomb yield function. The strain-softening behavior is represented by a piece-wise linearrelationship between the Mohr-Coulomb strength parameters and the deviatoric plastic strain. To assess the reliability of the proposed finite element approach,comparisons of the numerical solutions obtained by different finite element methods and meshes with various qualities are presented. Moreover,a landslide triggered by excavation in a real expressway construction project is analyzed by the presented finite element approach to demonstrate its applicability for practical engineering problems.
文摘After a long period without new NPPs (nuclear power plants) being designed or constructed in Europe, new build projects have been prepared, planned and are now under construction. The majority of these projects involve a new design with an enhanced level of safety, called GEN (Generation) III+. Although the serious events at the Japanese Fukushima Daiichi NPP caused by a tsunami led to a reduction in the number of new projects or even a phase out of nuclear power in some countries, only a slight reduction or delay of projects is expected globally. GEN III+ new build projects give rise to several economical, technical, human resource and organizational challenges. The paper starts with a discussion of these challenges and presents several activities that have been started to deal with them. It focuses on the development of human resources, coordinated approach of operators and suppliers can lead to the needs-oriented human resources development. particularly with operators and suppliers of GEN III+ NPPs. Only a successful execution of these projects. The focus must be on the
基金supported by the National Science and Technology Plan(Grant No.2013BAB06B01)the Graduate Student Scientific Research Innovation Projects of Regular Institutions of Jiangsu Province(Grant Nos.CXZZ11_0439&CXZZ13_0236)
文摘The principal means of conserving water and utilizing hydropower in China is to exploit the use of a series of reservoirs in a cascade. This method and its inherent engineering safety problems are receiving increasing attention nowadays. In the field of engineering safety analysis, much work has focused on single reservoir projects in the past few years, but there is little research available on the safety risk analysis of cascade reservoirs, either within China or internationally. Therefore, a framework for risk analysis on the cascade reservoir system based on the theory of system engineering is constructed in this article. A cascading failure model is established and the connection degree factor discussed. In addition, the importance degree of the subsystem, which can be calculated by combining the analytical hierarchy process and the entropy weight method, is explained. According to brittleness theory of a complex system, brittle risk entropy is proposed as a performance index for measuring the collapse uncertainty of the cascade reservoir system. In addition, the brittle risk of the cascade reservoir system is predicted, which provides a reference for safety analysis in water conservation and hydropower construction projects in China.