Catastrophic Response Of The Aboveground Structure Due To Progressive Collapse Of Neighboring Underground Structure Under Its Internal Blast Loading

As the underground structure suffers from terrorist bomb attacks, not only be agreat threat to life and property, but also a series of secondary disasters may betriggered if some critical components of the structure breakdown due to the explosion,which will lead to progressive collapse of the underground structure. In this paper, athorough research to the catastrophic response of the frame structure, frame shear wallstructure and space grid structure, due to progressive collapse of the neighboringunderground structure under its internal blast loading, has been made. The main workand achievement are as follows:(1) ANSYS/LS-DYNA is used to establish some undergroundstructure-soil-aboveground structure coupling models, and Three-Stage SimulationMethod, which is put forward by our research group, is adopted to analyzecatastrophic response of the aboveground structure, due to progressive collapse of theneighboring underground structure under its internal blast loading. By comparing thetilt response of the frame shear wall structure with raft foundation using AlternativeLoad Path Method, Direct Simulation Method and Three-Stage Simulation Method(TSSM), the TSSM is proved to be practical.(2) By comparing the catastrophic response of frame structure and frame shearwall structure of the same basic type, including raft foundation, basement foundationand piled raft foundation, due to progressive collapse of the neighboring undergroundstructure under its internal blast loading, it is found that the change of structure typecan not improve the performance of the overturning effect for the structure with raftfoundation, contrarily the tilt response of the frame shear wall structure is greater thanthat of the frame structure; however, compared with the frame structure withbasement or piled raft foundation, the tilt response of the frame shear wall structurewith basement or piled raft foundation decreases to some extent.(3) By comparing the catastrophic response of double-layer grid structure withindependent foundation and strip foundation due to progressive collapse of theneighboring underground structure under its internal blast loading, it is found that thedamage of the double-layer grid structure with independent foundation is moreserious than that with strip foundation; the nearer the distance between the member ofthe grid structure and the underground structure, the greater the change in amplitudeof the axial force of the members, and the axial force variation of the members at the top of the column is much larger than those of non-column top; the failure mode ofthe grid structure with independent foundation and strip foundation is basicallyidentical, which shows sunken-style deformation in the X-direction and tilt-styledeformation in the Y-direction.(4) By comparing the catastrophic response of double-layer reticulated shellstructure with independent foundation and strip foundation due to progressivecollapse of the neighboring underground structure under its internal blast loading, it isfound that the damage of the double-layer reticulated shell structure with independentfoundation is more serious than that with strip foundation; the nearer the distancebetween the member of the reticulated shell structure and the underground structure,the greater the change in amplitude of the axial force of the members, and the axialforce variation of the members at the top of the column is much larger than those ofnon-column top; the failure mode of the reticulated shell structure with independentfoundation and strip foundation is basically identical, which shows overallsinking-style deformation in the X-direction and tilt-style deformation in theY-direction. Compared with the grid structure, the reticulated shell structure also bearsthe horizontal loads besides the vertical loads, which causes that the destruction of thesoil near the reticulated shell structure is more serious than that of the soil near thegrid structure.