Soft soil has low shear strength and its density is high;construction of embankments on them would cause problems such as large and non-uniform subsidence. One way to avoid these subsidence is using of geo-grid combin...Soft soil has low shear strength and its density is high;construction of embankments on them would cause problems such as large and non-uniform subsidence. One way to avoid these subsidence is using of geo-grid combined with cement and lime columns. Geo-grids due to their tensile strength, and cement and lime columns due to their bearing capacity and their body friction, reduce embankment subsidence. Extensive researches have been done in order to reduce the subsidence of the embankments located on the roads, but few studies have being done about the inclined embankments on soft soil layers. In this paper, the road embankment has been located on inclined soft soil layers;the study will try to reduce embankment subsidence and uniform them using geo-grid combined with cement and lime column subsidence. The results show that the realization of this issue will cause subsidence reduction and uniformity in the embankment surface.展开更多
An experimental study on concrete filled steel tube columns with rectangular section subjected to compressionflexure-torsion combined action has been carried out. The failure modes and load-deformation hysteretic rela...An experimental study on concrete filled steel tube columns with rectangular section subjected to compressionflexure-torsion combined action has been carried out. The failure modes and load-deformation hysteretic relations were obtained. Based on the principles of classical material mechanics, the relations between the torsion curvature of the section and the shear strain of the fiber on the section were established. Then the strain distribution on the rectangular section of concrete filled steel tube columns subjected to torsion was analyzed. The three-dimensional refined finite element model was also built, in order to make the precision verification. The matrix forms of the relation between the torsion curvature of the section and the shear strain of the fiber on the section were derived, and introduced into the fiber beam model considering nonlinear torsion effect on the section. The comparison between test results and calculation results showed that the fiber beam model considering nonlinear torsion effect had high modeling efficiency and solution precision for predicting the torsion behavior of concrete filled steel tube columns with rectangular sections, and was suitable for analyzing the dynamic response of various structures subjected to the combined cyclic load caused by the earthquake load.展开更多
Ocean platforms are subjected to a variety of environment loads,such as those from winds,waves,currents,etc.In this study,the torsion problems of a gravity platform column with cracks under wind load were investigated...Ocean platforms are subjected to a variety of environment loads,such as those from winds,waves,currents,etc.In this study,the torsion problems of a gravity platform column with cracks under wind load were investigated.The column was assumed to be a composite cylinder.Therefore the torsion fracture problem of a composite cylinder was considered,and new boundary integral equations for the Saint-Venant torsion problem of a composite cylinder with curvilinear cracks were derived.The problem was reduced to solving the boundary integral equations on every boundary.By using the new boundary element method,the torsion problem of the gravity platform column with a straight crack under various wind loads was calculated.The obtained results were compared with those obtained for a torsion problem of the same column without cracks to prove the applicability of the present method.The comparison showed that the detrimental effect of cracks in a column should be considered in marine engineering.展开更多
文摘Soft soil has low shear strength and its density is high;construction of embankments on them would cause problems such as large and non-uniform subsidence. One way to avoid these subsidence is using of geo-grid combined with cement and lime columns. Geo-grids due to their tensile strength, and cement and lime columns due to their bearing capacity and their body friction, reduce embankment subsidence. Extensive researches have been done in order to reduce the subsidence of the embankments located on the roads, but few studies have being done about the inclined embankments on soft soil layers. In this paper, the road embankment has been located on inclined soft soil layers;the study will try to reduce embankment subsidence and uniform them using geo-grid combined with cement and lime column subsidence. The results show that the realization of this issue will cause subsidence reduction and uniformity in the embankment surface.
文摘An experimental study on concrete filled steel tube columns with rectangular section subjected to compressionflexure-torsion combined action has been carried out. The failure modes and load-deformation hysteretic relations were obtained. Based on the principles of classical material mechanics, the relations between the torsion curvature of the section and the shear strain of the fiber on the section were established. Then the strain distribution on the rectangular section of concrete filled steel tube columns subjected to torsion was analyzed. The three-dimensional refined finite element model was also built, in order to make the precision verification. The matrix forms of the relation between the torsion curvature of the section and the shear strain of the fiber on the section were derived, and introduced into the fiber beam model considering nonlinear torsion effect on the section. The comparison between test results and calculation results showed that the fiber beam model considering nonlinear torsion effect had high modeling efficiency and solution precision for predicting the torsion behavior of concrete filled steel tube columns with rectangular sections, and was suitable for analyzing the dynamic response of various structures subjected to the combined cyclic load caused by the earthquake load.
基金supported by the National High-Technology Research and Development Program of China (No.2007AA09Z317)
文摘Ocean platforms are subjected to a variety of environment loads,such as those from winds,waves,currents,etc.In this study,the torsion problems of a gravity platform column with cracks under wind load were investigated.The column was assumed to be a composite cylinder.Therefore the torsion fracture problem of a composite cylinder was considered,and new boundary integral equations for the Saint-Venant torsion problem of a composite cylinder with curvilinear cracks were derived.The problem was reduced to solving the boundary integral equations on every boundary.By using the new boundary element method,the torsion problem of the gravity platform column with a straight crack under various wind loads was calculated.The obtained results were compared with those obtained for a torsion problem of the same column without cracks to prove the applicability of the present method.The comparison showed that the detrimental effect of cracks in a column should be considered in marine engineering.
