This paper introduces the seismic physical modeling technology in the CNPC Key Lab of Geophysical Exploration. It includes the seismic physical model positioning system, the data acquisition system, sources, transduce...This paper introduces the seismic physical modeling technology in the CNPC Key Lab of Geophysical Exploration. It includes the seismic physical model positioning system, the data acquisition system, sources, transducers, model materials, model building techniques, precision measurements of model geometry, the basic principles of the seismic physical modeling and experimental methods, and two physical model examples.展开更多
Underground lifeline engineering (ULE for short) in modern city demands the appreciation of an active fault in buried bedrock . Generally speaking , a large number of urban geological textures of a basement may all be...Underground lifeline engineering (ULE for short) in modern city demands the appreciation of an active fault in buried bedrock . Generally speaking , a large number of urban geological textures of a basement may all be simplified into a dual geological texture model , i. e., the upper part of the basement consists of loose covering layer and the lower part consists of bedrock . The study of an active fault should include three parts of contents , i . e ., to determine the lower time limit of activity of the fault , and the time limit must be recognized by both of designing engineers and geologists ; on the basis of the studies of repetition periods of earthquake occurrence to deter mine whether the fault moves or not during the allowed time of efficacy of buildings and constructions ; for the sake of engineering practice , the active rate of the fault must be given . The fault with different active mechanism has different effects on the ULE . The authors studied the effect of lateral non-uniform overburden site on the ULE by means of the supersonic earthquake modelling . Owing to the lateral non - uniformity of the covering sediments , there occurs an obvious jump of amplitude of the seismic wave propagation near the contact surface between two different sedi ments . In addition , from the modelling experiment curves it may be seen that the different focus mechanisms and different medium characters may also exert an effect in different degrees .展开更多
In this paper, an experimental and analytical study of two half-scale steel X-braced flames with equal nominal shear strength under cyclic loading is described. In these tests, all members except the braces are simila...In this paper, an experimental and analytical study of two half-scale steel X-braced flames with equal nominal shear strength under cyclic loading is described. In these tests, all members except the braces are similar. The braces are made of various steel grades to monitor the effects of seismic excitation. Internal stiffeners are employed to limit the local buckling and increase the fracture life of the steel bracing. A heavy central core is introduced at the intersection of the braces to decrease their effective length. Recent seismic specifications are considered in the design of the X-braced frame members to verify their efficiency. The failure modes of the X-braced frames are also illustrated. It is observed that the energy dissipation capacity, ultimate load capacity and ductility of the system increase considerably by using lower grade steel and proposed detailing. Analytical modeling of the specimens using nonlinear finite element software supports the experimental findings.展开更多
文摘This paper introduces the seismic physical modeling technology in the CNPC Key Lab of Geophysical Exploration. It includes the seismic physical model positioning system, the data acquisition system, sources, transducers, model materials, model building techniques, precision measurements of model geometry, the basic principles of the seismic physical modeling and experimental methods, and two physical model examples.
基金The paper is one Part of a project supported by National Education Commitce Funds for Doctoral Faculty
文摘Underground lifeline engineering (ULE for short) in modern city demands the appreciation of an active fault in buried bedrock . Generally speaking , a large number of urban geological textures of a basement may all be simplified into a dual geological texture model , i. e., the upper part of the basement consists of loose covering layer and the lower part consists of bedrock . The study of an active fault should include three parts of contents , i . e ., to determine the lower time limit of activity of the fault , and the time limit must be recognized by both of designing engineers and geologists ; on the basis of the studies of repetition periods of earthquake occurrence to deter mine whether the fault moves or not during the allowed time of efficacy of buildings and constructions ; for the sake of engineering practice , the active rate of the fault must be given . The fault with different active mechanism has different effects on the ULE . The authors studied the effect of lateral non-uniform overburden site on the ULE by means of the supersonic earthquake modelling . Owing to the lateral non - uniformity of the covering sediments , there occurs an obvious jump of amplitude of the seismic wave propagation near the contact surface between two different sedi ments . In addition , from the modelling experiment curves it may be seen that the different focus mechanisms and different medium characters may also exert an effect in different degrees .
文摘In this paper, an experimental and analytical study of two half-scale steel X-braced flames with equal nominal shear strength under cyclic loading is described. In these tests, all members except the braces are similar. The braces are made of various steel grades to monitor the effects of seismic excitation. Internal stiffeners are employed to limit the local buckling and increase the fracture life of the steel bracing. A heavy central core is introduced at the intersection of the braces to decrease their effective length. Recent seismic specifications are considered in the design of the X-braced frame members to verify their efficiency. The failure modes of the X-braced frames are also illustrated. It is observed that the energy dissipation capacity, ultimate load capacity and ductility of the system increase considerably by using lower grade steel and proposed detailing. Analytical modeling of the specimens using nonlinear finite element software supports the experimental findings.
