针对平钢板-混凝土复合结构或单一波纹钢结构在抗爆性能方面具有一定局限性的问题,根据波纹钢能够提高混凝土板抗爆性能的技术,提出了改变波纹钢夹角的加固方法。首先,将有限元法与光滑粒子法(finite element method-smoothed particle ...针对平钢板-混凝土复合结构或单一波纹钢结构在抗爆性能方面具有一定局限性的问题,根据波纹钢能够提高混凝土板抗爆性能的技术,提出了改变波纹钢夹角的加固方法。首先,将有限元法与光滑粒子法(finite element method-smoothed particle hydrodynamics,简称FEM-SPH)耦合,建立接触爆炸荷载下波纹钢-混凝土板复合结构三维精细化数值仿真模型;其次,对波纹钢-混凝土板复合结构破坏模式的试验结果和模拟结果进行对比;最后,研究波纹钢夹角变化下复合结构的毁伤特征。结果表明:90o夹角波纹钢的跨中位移、中心点处加速度和能量吸收值较30o夹角波纹钢分别减小17.9%、88.6%和59.4%;复合结构的损伤范围随着波纹钢夹角的增大而减小,表现为混凝土板的爆坑和贯穿破坏;不同夹角波纹钢复合结构中混凝土板的失效体积随着波纹钢夹角的增加而减小,而复合结构的能量吸收值随着波纹钢夹角的增加而增大,主要由于因波纹钢会增加应力波的反射次数,从而达到减波吸能的效果。该研究成果可为波纹钢-混凝土板复合结构在结构抗爆防护领域的应用提供理论基础。展开更多
Although intensive research of the influence of ground motion duration on structural cumulative damage has been carried out, the influence of dynamic responses in underground tunnels remains a heated debate. This stud...Although intensive research of the influence of ground motion duration on structural cumulative damage has been carried out, the influence of dynamic responses in underground tunnels remains a heated debate. This study attempts to highlight the importance of the ground motion duration effect on hydraulic tunnels subjected to deep-focus earthquakes. In the study, a set of 18 recorded accelerograms with a wide-range of durations were employed. A spectrally equivalent method serves to distinguish the effect of duration from other ground motion features, and then the seismic input model was simulated using SV-wave excitation based on a viscous-spring boundary, which was verified by the time-domain waves analysis method. The nonlinear analysis results demonstrate that the risk of collapse of the hydraulic tunnel is higher under long-duration ground motion than that of short-duration ground motion of the same seismic intensity. In a low intensity earthquake, the ground motion duration has little effect on the damage energy consumption of a hydraulic tunnel lining, but in a high intensity earthquake, dissipation of the damage energy and damage index of concrete shows a nonlinear growth trend accompanied by the increase of ground motion duration, which has a great influence on the deformation and stress of hydraulic tunnels, and correlation analysis shows that the correlation coefficient is greater than 0.8. Therefore, the duration of ground motion should be taken into consideration except for its intensity and frequency content in the design of hydraulic tunnel, and evaluation of seismic risk.展开更多
文摘针对平钢板-混凝土复合结构或单一波纹钢结构在抗爆性能方面具有一定局限性的问题,根据波纹钢能够提高混凝土板抗爆性能的技术,提出了改变波纹钢夹角的加固方法。首先,将有限元法与光滑粒子法(finite element method-smoothed particle hydrodynamics,简称FEM-SPH)耦合,建立接触爆炸荷载下波纹钢-混凝土板复合结构三维精细化数值仿真模型;其次,对波纹钢-混凝土板复合结构破坏模式的试验结果和模拟结果进行对比;最后,研究波纹钢夹角变化下复合结构的毁伤特征。结果表明:90o夹角波纹钢的跨中位移、中心点处加速度和能量吸收值较30o夹角波纹钢分别减小17.9%、88.6%和59.4%;复合结构的损伤范围随着波纹钢夹角的增大而减小,表现为混凝土板的爆坑和贯穿破坏;不同夹角波纹钢复合结构中混凝土板的失效体积随着波纹钢夹角的增加而减小,而复合结构的能量吸收值随着波纹钢夹角的增加而增大,主要由于因波纹钢会增加应力波的反射次数,从而达到减波吸能的效果。该研究成果可为波纹钢-混凝土板复合结构在结构抗爆防护领域的应用提供理论基础。
基金National Key Research and Development Program of China under Grant No. 2018YFC0406903Yunnan Key Research and Development Program under Grant No. 2017IB014the Innovative Research Groups of the National Natural Science Foundation of China under Grant No. 51621092。
文摘Although intensive research of the influence of ground motion duration on structural cumulative damage has been carried out, the influence of dynamic responses in underground tunnels remains a heated debate. This study attempts to highlight the importance of the ground motion duration effect on hydraulic tunnels subjected to deep-focus earthquakes. In the study, a set of 18 recorded accelerograms with a wide-range of durations were employed. A spectrally equivalent method serves to distinguish the effect of duration from other ground motion features, and then the seismic input model was simulated using SV-wave excitation based on a viscous-spring boundary, which was verified by the time-domain waves analysis method. The nonlinear analysis results demonstrate that the risk of collapse of the hydraulic tunnel is higher under long-duration ground motion than that of short-duration ground motion of the same seismic intensity. In a low intensity earthquake, the ground motion duration has little effect on the damage energy consumption of a hydraulic tunnel lining, but in a high intensity earthquake, dissipation of the damage energy and damage index of concrete shows a nonlinear growth trend accompanied by the increase of ground motion duration, which has a great influence on the deformation and stress of hydraulic tunnels, and correlation analysis shows that the correlation coefficient is greater than 0.8. Therefore, the duration of ground motion should be taken into consideration except for its intensity and frequency content in the design of hydraulic tunnel, and evaluation of seismic risk.
