The seismic stability of a cracked dam was examined in this study. Geometric nonlinearity and large deformations, as well as the contact condition at the crack site, were taken into consideration. The location of pene...The seismic stability of a cracked dam was examined in this study. Geometric nonlinearity and large deformations, as well as the contact condition at the crack site, were taken into consideration. The location of penetrated cracks was first identified using the concrete plastic-damage model based on the nonlinear finite element method （FEM）. Then, the hard contact algorithm was used to simulate the crack interaction in the normal direction, and the Coloumb friction model was used to simulate the crack interaction in the tangential direction. After verification of numerical models through a case study, the seismic stability of the Koyna Dam with two types of penetrated cracks is discussed in detail with different seismic peak accelerations, and the collapse processes of the cracked dam are also presented. The results show that the stability of the dam with two types of penetrated cracks can be ensured in an earthquake with a magnitude of the original Koyna earthquake, and the cracked dam has a large earthquake-resistant margin. The failure processes of the cracked dam in strong earthquakes can be divided into two stages： the sliding stage and the overturning stage. The sliding stage ends near the peak acceleration, and the top block slides a long distance along the crack before the collapse occurs. The maximum sliding displacement of the top block will decrease with an increasing friction coefficient at the crack site.展开更多
In this paper,a novel type of isolator,named segmented intelligent isolation bearing(SIIB),is designed and manufactured,which can meet the requirements of seismic fortification under three seismic intensities,i.e.freq...In this paper,a novel type of isolator,named segmented intelligent isolation bearing(SIIB),is designed and manufactured,which can meet the requirements of seismic fortification under three seismic intensities,i.e.frequent intensity,basic intensity,and rare intensity.A theoretical formula for the output of the SIIB is established to provide a basis for the determination of the size of the SIIB.MRE and STMP used in SIIB were prepared,of which the changes of shear storage modulus and damping factor with the magnetic field under different strain are analyzed.The mechanical properties of the SIIB under small displacement,medium displacement,and large displacement are tested,respectively,and the hysteretic characteristics of force–displacement are analyzed.The dynamic mechanical model combining the rheological model,phenomenological model,and bilinear restoring force model is established to represent the behavior of the SIIB.The results showed that the theoretical results agree well with the experimental results,and the model can significantly reflect the dynamic characteristics of SIIB.展开更多
基金supported by the National Basic Research Program of China (973 Program, Grant No. 2007CB714104)the National Natural Science Foundation of China (Grant No. 50779011)the Innovative Project for Graduate Students of Jiangsu Province (Grant No. CX10B_202Z)
文摘The seismic stability of a cracked dam was examined in this study. Geometric nonlinearity and large deformations, as well as the contact condition at the crack site, were taken into consideration. The location of penetrated cracks was first identified using the concrete plastic-damage model based on the nonlinear finite element method （FEM）. Then, the hard contact algorithm was used to simulate the crack interaction in the normal direction, and the Coloumb friction model was used to simulate the crack interaction in the tangential direction. After verification of numerical models through a case study, the seismic stability of the Koyna Dam with two types of penetrated cracks is discussed in detail with different seismic peak accelerations, and the collapse processes of the cracked dam are also presented. The results show that the stability of the dam with two types of penetrated cracks can be ensured in an earthquake with a magnitude of the original Koyna earthquake, and the cracked dam has a large earthquake-resistant margin. The failure processes of the cracked dam in strong earthquakes can be divided into two stages： the sliding stage and the overturning stage. The sliding stage ends near the peak acceleration, and the top block slides a long distance along the crack before the collapse occurs. The maximum sliding displacement of the top block will decrease with an increasing friction coefficient at the crack site.
基金This work was the supported by National Natural Science Foundation of China[Grant No.51508237]the Primary Research and Development Plan of Jiangsu Province[Grant no.BE2017167]All data included in this study are available upon request by contact with the corresponding author.
文摘In this paper,a novel type of isolator,named segmented intelligent isolation bearing(SIIB),is designed and manufactured,which can meet the requirements of seismic fortification under three seismic intensities,i.e.frequent intensity,basic intensity,and rare intensity.A theoretical formula for the output of the SIIB is established to provide a basis for the determination of the size of the SIIB.MRE and STMP used in SIIB were prepared,of which the changes of shear storage modulus and damping factor with the magnetic field under different strain are analyzed.The mechanical properties of the SIIB under small displacement,medium displacement,and large displacement are tested,respectively,and the hysteretic characteristics of force–displacement are analyzed.The dynamic mechanical model combining the rheological model,phenomenological model,and bilinear restoring force model is established to represent the behavior of the SIIB.The results showed that the theoretical results agree well with the experimental results,and the model can significantly reflect the dynamic characteristics of SIIB.
