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近场和远场地震动作用下双层竖向重叠地铁隧道地震反应特性 总被引:2,自引:0,他引:2
基于江苏省的地震环境,研究近、远场地震动作用下的双层竖向重叠地铁隧道的地震反应特性,并与单层地铁隧道的地震反应特性进行比较。结果表明:在近场地震动作用下上下层隧道之间的相互作用对隧道的相对水平位移差具有放大作用,而在远场地震动作用下双层隧道的相对水平位移差与单层隧道的基本相同;在近、远场地震动作用下,上层隧道的相对水平位移差要比下层的大得多;在近场地震动作用下存在隧道拱肩外侧的地震应力大于拱肩内侧地震应力的现象,而在远场地震动作用下地铁隧道拱肩内侧的地震应力值最大;在近场地震动作用下双层隧道下层的地震应力幅值要比上层的地震应力幅值大,在远场地震动作用下则相反;在近、远场地震动作用下双层竖向重叠地铁隧道底部的峰值加速度与浅埋或深埋单层隧道的基本相同。 相似文献
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Three regimes: near-, middle- and far-fields of underwater explosion are proposed in this study aiming at providing an overview on the responses of submerged slender structure by pulsating bubble. In the near-field, the material starts to yield, thus leading to structure breakdown immediately; remarkable structural global elastic deformation occurs in the middle-field as well as substantial movement; and a structure moves as a rigid body with negligible deformation for the far-field. Equivalent dimensionless parameters are obtained by two different dimensional analysis methods, among which a dominant similarity parameter is found out. Thus, a scaling law providing us with a relation between structural global response and the dominant similarity parameter is yielded, which can be used for demarcating the three regimes quantitatively. To demonstrate, three models corresponding to typical submarine parameters are performed in the case studies. Quantitative criterion of the three regimes is presented along with the regime diagrams. The structural global response features such as the deformation and maximal acceleration/speed of different regimes are provided as well. 相似文献
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Seismic Responses of Asymmetric Base-Isolated Structures under Near-Fault Ground Motion 总被引:1,自引:0,他引:1
An inter-story shear model of asymmetric base-isolated structures incorporating deformation of each isolation bearing was built, and a method to simultaneously simulate bi-directional near-fault and far-field ground motions was proposed. A comparative study on the dynamic responses of asymmetric base-isolated structures under near-fault and far-field ground motions were conducted to investigate the effects of eccentricity in the isolation system and in the superstructures, the ratio of the uncoupled torsional to lateral frequency of the superstructure and the pulse period of near-fault ground motions on the nonlinear seismic response of asymmetric base-isolated structures. Numerical results show that eccentricity in the isolation system makes asymmetric base-isolated structure more sensitive to near-fault ground motions, and the pulse period of near-fault ground motions plays an import role in governing the seismic responses of asymmetric base-isolated structures. 相似文献
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