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
Egypt construction projects are associated with different levels of risks. The lack of familiarity of project management standards is one of the common risks in the construction industry in Egypt. The main aim of this...Egypt construction projects are associated with different levels of risks. The lack of familiarity of project management standards is one of the common risks in the construction industry in Egypt. The main aim of this paper is to identify the most significant risk factors affecting highway construction project in Egypt to decrease the likelihood and impact of those risks. The research method starts with extensive literature review to provide a prime risk factors list which was also augmented to expertise to reach final risk factor list which contains all risks that may be faced during highway construction. Subsequently, a set of 12 risk groups consisting of 73 risks was selected and a questionnaire survey was conducted to determine the likelihood and consequences of the identified risks. Later, a software application was developed using MATLAB to facilitate risk evaluation of highways projects. Results indicated that the risk factors arise from owner side is one of the most common risk factors in the construction industry in Egypt as the owner in the majority of construction project in Egypt is the governmental sector, however, the overall project risk of highway construction projects in Egypt is considered as at a medium level.展开更多
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Egypt construction projects are associated with different levels of risks. The lack of familiarity of project management standards is one of the common risks in the construction industry in Egypt. The main aim of this paper is to identify the most significant risk factors affecting highway construction project in Egypt to decrease the likelihood and impact of those risks. The research method starts with extensive literature review to provide a prime risk factors list which was also augmented to expertise to reach final risk factor list which contains all risks that may be faced during highway construction. Subsequently, a set of 12 risk groups consisting of 73 risks was selected and a questionnaire survey was conducted to determine the likelihood and consequences of the identified risks. Later, a software application was developed using MATLAB to facilitate risk evaluation of highways projects. Results indicated that the risk factors arise from owner side is one of the most common risk factors in the construction industry in Egypt as the owner in the majority of construction project in Egypt is the governmental sector, however, the overall project risk of highway construction projects in Egypt is considered as at a medium level.
