Based on seismic damage data of gas pipeline network, obtained through scientific investigation in 18 cities/counties, seismic damage appearances of gas pipeline which are made of different materials are summarized and compared, and their impacts on gas supply function are studied. Then the use status of pipeline of different materials and the reasons of causing damages are analyzed. And some earthquake resistant countermeasures are proposed to reduce the seismic damages.
The seismic damage and loss of service of pipeline engineering may have great influence on the society, so the seismic research of pipeline engineering had always been highly valued. In this paper, the seismic damage characteristics of pipeline and vulnerability of water pipeline system in Wenchuan earthquake are analyzed, some revelations have been presented. The seismic capacity of pipeline engineering in some towns and cities was not adequate, the pipeline systems suffered great losses in Wenchuan Earthquake, and effective seismic countermeasures should be considered in design and construction of water pipeline system in order to improve this situation.
Recent earthquakes indicate that tunnels can not be considered as structures invulnerable to earthquakes, especially in areas crossing a fault. Seismic damage, such as falling, fissure and dislocation of the tunnel lining may happen at location of fault. Under the action of earthquake, two kinds of loads may occur, which are the fault movement and the function of seismic wave. In order to analyze the seismic damage to cross-fault tunnel, the seismic characters under each kind of load are studied by using finite element method. Some meaningful conclusions have been achieved. Under the condition of strike-slip fault, the stress of tunnel concentrated at the position of fault, and the stress in both active and driven plate is small. The influence degree of reverse fault is between the other two kinds of faults. By enhancing the lining materials stiffness, the displacement of tunnel decreased, but the peak acceleration and first principle stress of it increased and the position of max-displacement also changed.
This article reviews the discourse-based machine translation evaluation metrics. According to different methods of using, machine translation evaluation based on discourse is divided into two categories: evaluation based on discourse structure and evaluation based on discourse features. For these two different categories, we introduce their representative works, and compare the advantages and disadvantages of each method. Finally, we summarize the evaluation metrics based on discourse, points out the problems to be paid attention to when evaluating, and predicts the future development trends.
Seismic damage, such as falling, fissure and dislocation of the lining may happen at location of fault movement. The model of enhancing stiffness and that of adding seismic decrease layer are built by the finite element software MIDAS to compare the two earthquake-resistant methods. Some useful results are obtained: a)The displacement is decreased, but the peak acceleration and first principle stress of the lining are increased in the model of enhancing the lining materials stiffness. b) The displacement, peak acceleration and first principle stress are all decreased in the model of adding seismic decrease layer. c) The max-displacement when using c20 as lining material or adding seismic decrease layer is in the area of fault, but that of the model when using c40 as lining material is in the area of entrance.
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