Method of testing for dynamic output forces from jet elements is studied, the handwidth is large in testing with this method. By establishing a model of the test system and simulating it, principles of how inherent fe...Method of testing for dynamic output forces from jet elements is studied, the handwidth is large in testing with this method. By establishing a model of the test system and simulating it, principles of how inherent features of the test system affect the dynamic force test are found out. Thus a theoretical foundation is given for the design and error modification to the actual test system.展开更多
The source parameters of the Yajiang earthquake sequence are calculated based on spectral analysis of S wave data recorded by the Chengdu Digital Seismic Network. Analysis of the source parameters in different periods...The source parameters of the Yajiang earthquake sequence are calculated based on spectral analysis of S wave data recorded by the Chengdu Digital Seismic Network. Analysis of the source parameters in different periods are made,The obtained results are:(1)the relationship between M S(seismic moment), M W(moment magnitude)and M L(local magnitude),which fits the data of Yajiang earthquake sequence; (2) the decreasing corner frequency from 1.4 before the M5.0 earthquake to 1.3 afterwards, and then to 1.2 after the M6.0 event; (3) the obvious difference in the source parameters between foreshocks and aftershocks,which may be indicators for earthquake prediction.展开更多
In this paper,the soil-pile system of O-cell test of pile is simplified as an axi-symmetric problem.By using aggregation of quadrilateral isoparametric elements to simulate pile and soil,setting Goodman's elements...In this paper,the soil-pile system of O-cell test of pile is simplified as an axi-symmetric problem.By using aggregation of quadrilateral isoparametric elements to simulate pile and soil,setting Goodman's elements between pile and soils,a method of numerical simulation analysis on O-cell test of pile is presented with the consideration of nonlinear mechanical behavior of soils and pile-soil interface.The method is applied to the analysis of a case of O-cell test of pile.The load-displacement curves and axial force curves of upper pile and lower pile obtained from the O-cell test of pile are fitted,and parameters of the mechanical model of soils and interface are determined.Analysis results validate that the numerical simulation analysis method put forward in this paper is applicable.Furthermore,the interaction and influence of upper pile and lower pile in the O-cell test are also studied with the method.The result shows that if load box is located in a soil layer with fine mechanical behavior,the interaction of upper pile and lower pile in O-cell test can be ignored generally.展开更多
To focus on the key scientific problem of process control of dynamic catastrophe of high dams,presented for the first time are the modelling theory of liquid-gas-solid tri-phase coupling of the air-cushion isolation c...To focus on the key scientific problem of process control of dynamic catastrophe of high dams,presented for the first time are the modelling theory of liquid-gas-solid tri-phase coupling of the air-cushion isolation control of high dams and its numerical simulation method,and theoretical description of the complicated dynamics problem of the tri-phase coupling-thermodynamics state-material-contact bi-nonlinearity,as well as the simulation analysis of the key effects of dynamic catastrophe of the air-cushion isolated high dam engineering.The analytic solution of plane-wave with rigid-dam body was created.The simulation comparison of dynamic catastrophe processes of 305 m Jinping arch dam with and without seismic control was carried out,and the results were basically in agreement with that obtained from the large shaking table tests,and verify each other.The entire air-chamber and optimized air-cushion with varying thickness were presented to develop a optimization method.The large shaking table tests of the isolated dam model,which is satisfied with the basic dynamic similarity relations,were performed for the first time.The test data seemed to be convincing and were in agreement with the dynamic simulation results of the tested model,thereby providing an experimental verification to the simulation theory and method.The combination experiments of theoretical model and physical model demonstrated that the hydrodynamic pressure of high arch dams can be reduced by more than 70% as well as the first and third principle stresses of the dam body reduced by more than 20%-30%,thereby the global anti-seismic capacity of the high dam being improved significantly.The results have shown that the air-cushion isolation is the prior developing direction of structural control technology of high concrete dams.展开更多
文摘Method of testing for dynamic output forces from jet elements is studied, the handwidth is large in testing with this method. By establishing a model of the test system and simulating it, principles of how inherent features of the test system affect the dynamic force test are found out. Thus a theoretical foundation is given for the design and error modification to the actual test system.
文摘The source parameters of the Yajiang earthquake sequence are calculated based on spectral analysis of S wave data recorded by the Chengdu Digital Seismic Network. Analysis of the source parameters in different periods are made,The obtained results are:(1)the relationship between M S(seismic moment), M W(moment magnitude)and M L(local magnitude),which fits the data of Yajiang earthquake sequence; (2) the decreasing corner frequency from 1.4 before the M5.0 earthquake to 1.3 afterwards, and then to 1.2 after the M6.0 event; (3) the obvious difference in the source parameters between foreshocks and aftershocks,which may be indicators for earthquake prediction.
文摘In this paper,the soil-pile system of O-cell test of pile is simplified as an axi-symmetric problem.By using aggregation of quadrilateral isoparametric elements to simulate pile and soil,setting Goodman's elements between pile and soils,a method of numerical simulation analysis on O-cell test of pile is presented with the consideration of nonlinear mechanical behavior of soils and pile-soil interface.The method is applied to the analysis of a case of O-cell test of pile.The load-displacement curves and axial force curves of upper pile and lower pile obtained from the O-cell test of pile are fitted,and parameters of the mechanical model of soils and interface are determined.Analysis results validate that the numerical simulation analysis method put forward in this paper is applicable.Furthermore,the interaction and influence of upper pile and lower pile in the O-cell test are also studied with the method.The result shows that if load box is located in a soil layer with fine mechanical behavior,the interaction of upper pile and lower pile in O-cell test can be ignored generally.
基金supported by the National Natural Science Foundation of China (Grant No. 90715026)
文摘To focus on the key scientific problem of process control of dynamic catastrophe of high dams,presented for the first time are the modelling theory of liquid-gas-solid tri-phase coupling of the air-cushion isolation control of high dams and its numerical simulation method,and theoretical description of the complicated dynamics problem of the tri-phase coupling-thermodynamics state-material-contact bi-nonlinearity,as well as the simulation analysis of the key effects of dynamic catastrophe of the air-cushion isolated high dam engineering.The analytic solution of plane-wave with rigid-dam body was created.The simulation comparison of dynamic catastrophe processes of 305 m Jinping arch dam with and without seismic control was carried out,and the results were basically in agreement with that obtained from the large shaking table tests,and verify each other.The entire air-chamber and optimized air-cushion with varying thickness were presented to develop a optimization method.The large shaking table tests of the isolated dam model,which is satisfied with the basic dynamic similarity relations,were performed for the first time.The test data seemed to be convincing and were in agreement with the dynamic simulation results of the tested model,thereby providing an experimental verification to the simulation theory and method.The combination experiments of theoretical model and physical model demonstrated that the hydrodynamic pressure of high arch dams can be reduced by more than 70% as well as the first and third principle stresses of the dam body reduced by more than 20%-30%,thereby the global anti-seismic capacity of the high dam being improved significantly.The results have shown that the air-cushion isolation is the prior developing direction of structural control technology of high concrete dams.
