Dynamic responses of a multi-storey building without or with a sliding base-isolation device for ground shock induced by an in-tunnel explosion are numerically analyzed. The effect of an adjacent tunnel in between the...Dynamic responses of a multi-storey building without or with a sliding base-isolation device for ground shock induced by an in-tunnel explosion are numerically analyzed. The effect of an adjacent tunnel in between the building and the explosion tunnel, which affects ground shock propagation , is considered in the analysis. Different modeling methods, such as the eight-node equal-parametric finite element and mass-lumped system, are used to establish the coupling model consisting of the two adjacent tunnels, the surrounding soil medium with the Lysmer viscous boundary condition, and the multi-storey building with or without the sliding base-isolation device. In numerical calculations , a continuous friction model, which is different from the traditional Coulomb friction model, is adopted to improve the computational efficiency and reduce the accumulated errors. Some example analyses are subsequently performed to study the response characteristics of the building and the sliding base-isolation device to ground shock. The effect of the adjacent tunnel in between the building and the explosion tunnel on the ground shock wave propagation is also investigated. The final conclusions based on the numerical results will provide some guidance in engineering practice.展开更多
Two large explosion trials (5 000 kg TNT and 500 kg ANFO) were conducted in Woomera, Australia in April/May 2006. Advance Protective Technologies for Engineering Structures (APTES) group tested 2 large single-storey c...Two large explosion trials (5 000 kg TNT and 500 kg ANFO) were conducted in Woomera, Australia in April/May 2006. Advance Protective Technologies for Engineering Structures (APTES) group tested 2 large single-storey concrete modules with individual components such as doors, windows and tiled panels. A description of the trial and details of various modules tested in these trials are presented in the paper. Numerical modelling and simulations are performed using computer programs, CONWEP, AIR3D and AUTODYN. A comparison of the pressure time histories obtained using these codes is made along with the concluding remarks.展开更多
A random medium model is developed to describe damage and failure of concrete.In the first place,to simulate the evolving cracks in a mesoscale,the concrete is randomly discretized as irregular finite elements.Moreove...A random medium model is developed to describe damage and failure of concrete.In the first place,to simulate the evolving cracks in a mesoscale,the concrete is randomly discretized as irregular finite elements.Moreover,the cohesive elements are inserted into the adjacency of finite elements as the possible cracking paths.The spatial variation of the material properties is considered using a 2-D random field,and the stochastic harmonic function method is adopted to simulate the sample of the fracture energy random field in the analysis.Then,the simulations of concrete specimens are given to describe the different failure modes of concrete under tension.Finally,based on the simulating results,the probability density distributions of the stress-strain curves are solved by the probability density evolution methods.Thus,the accuracy and efficiency of the proposed model are verified in both the sample level and collection level.展开更多
In this study,a numerical model,which can capture the full process of the development of seepage passages,the collapse of dams and the failure due to overtopping,is proposed for earth-rock dams.The critical incipient ...In this study,a numerical model,which can capture the full process of the development of seepage passages,the collapse of dams and the failure due to overtopping,is proposed for earth-rock dams.The critical incipient velocity for the occurrence of seepage failure is derived by analyzing the forces acting on soil particles in the seepage passage.The sediment transport formula is proposed to simulate the erosion process and the evolution of breach within the dam.In this model,the grain size distribution,the compaction density and the strength of dam materials are reasonably accounted for.Furthermore,the influences of the direction of seepage paths,the slope of the dam and the velocity of water flow on the amount of erosion are also taken into consideration.The proposed model and the corresponding numerical programs are employed to simulate the development of breaches and discharge of two typical cases due to seepage failure.The development of breaches,the history of discharge and the peak flood flux predicted by the numerical models are rather comparable to the measured data,which confirms the validity of the proposed model and the feasibility of applying the model in evaluating the disaster consequences and preparing the emergency counter measurements in the case of dam collapse.展开更多
基金Supported by National Science Fund for Distinguished Young Scholars of China (No. 50425824)National Natural Science Foundation of China (No. 50528808)
文摘Dynamic responses of a multi-storey building without or with a sliding base-isolation device for ground shock induced by an in-tunnel explosion are numerically analyzed. The effect of an adjacent tunnel in between the building and the explosion tunnel, which affects ground shock propagation , is considered in the analysis. Different modeling methods, such as the eight-node equal-parametric finite element and mass-lumped system, are used to establish the coupling model consisting of the two adjacent tunnels, the surrounding soil medium with the Lysmer viscous boundary condition, and the multi-storey building with or without the sliding base-isolation device. In numerical calculations , a continuous friction model, which is different from the traditional Coulomb friction model, is adopted to improve the computational efficiency and reduce the accumulated errors. Some example analyses are subsequently performed to study the response characteristics of the building and the sliding base-isolation device to ground shock. The effect of the adjacent tunnel in between the building and the explosion tunnel on the ground shock wave propagation is also investigated. The final conclusions based on the numerical results will provide some guidance in engineering practice.
文摘Two large explosion trials (5 000 kg TNT and 500 kg ANFO) were conducted in Woomera, Australia in April/May 2006. Advance Protective Technologies for Engineering Structures (APTES) group tested 2 large single-storey concrete modules with individual components such as doors, windows and tiled panels. A description of the trial and details of various modules tested in these trials are presented in the paper. Numerical modelling and simulations are performed using computer programs, CONWEP, AIR3D and AUTODYN. A comparison of the pressure time histories obtained using these codes is made along with the concluding remarks.
基金supported by the National Natural Science Foundation of China(Grant Nos.90715033,51261120374,51208374)
文摘A random medium model is developed to describe damage and failure of concrete.In the first place,to simulate the evolving cracks in a mesoscale,the concrete is randomly discretized as irregular finite elements.Moreover,the cohesive elements are inserted into the adjacency of finite elements as the possible cracking paths.The spatial variation of the material properties is considered using a 2-D random field,and the stochastic harmonic function method is adopted to simulate the sample of the fracture energy random field in the analysis.Then,the simulations of concrete specimens are given to describe the different failure modes of concrete under tension.Finally,based on the simulating results,the probability density distributions of the stress-strain curves are solved by the probability density evolution methods.Thus,the accuracy and efficiency of the proposed model are verified in both the sample level and collection level.
基金supported by the National Basic Research Program of China ("973" Program) (Grant No. 2007CB714103)the National Natural Science Foundation of China (Grant No. 90815024)
文摘In this study,a numerical model,which can capture the full process of the development of seepage passages,the collapse of dams and the failure due to overtopping,is proposed for earth-rock dams.The critical incipient velocity for the occurrence of seepage failure is derived by analyzing the forces acting on soil particles in the seepage passage.The sediment transport formula is proposed to simulate the erosion process and the evolution of breach within the dam.In this model,the grain size distribution,the compaction density and the strength of dam materials are reasonably accounted for.Furthermore,the influences of the direction of seepage paths,the slope of the dam and the velocity of water flow on the amount of erosion are also taken into consideration.The proposed model and the corresponding numerical programs are employed to simulate the development of breaches and discharge of two typical cases due to seepage failure.The development of breaches,the history of discharge and the peak flood flux predicted by the numerical models are rather comparable to the measured data,which confirms the validity of the proposed model and the feasibility of applying the model in evaluating the disaster consequences and preparing the emergency counter measurements in the case of dam collapse.
