海啸波对海底悬跨管道受力分析

研究地震海啸行移时通过海底悬跨管段区域时对管道的影响。假设悬跨段两端不受地震海啸影响,因为海啸为长波,本文根据传统Morison方程计算了海底悬跨管道在行移的海啸波浪荷载作用下的受力情况,并应用有限元软件ADINA进行了建模分析,通过模拟结果分析海啸波浪对海底悬跨管道受力的影响并判断是否会对海底管道造成破坏性影响。     

Large-scale Disasters on World Heritage and Cultural Heritage in Japan: Significant Impacts and Sustainable Management Cases

Abstract

On 11 March 2011, the East Japan Great Earthquake occurred off the east coast of Japan. This magnitude 9 earthquake caused a tsunami of 8–9 m in height, which subsequently reached an upstream height of up to 40 m, causing extensive damage over a 500-km span along the east coast of Japan. Damage was caused to 295 National Cultural Properties of Japan, most of which was due to the associated tsunamis rather than the earthquake. Particularly, significant damage was seen in the coastal cultural landscapes. In addition, Japan has extremely large typhoons every year. In recent years, it has not been unusual to see typhoon-caused storms, heavy rains and flooding, causing intensive damage such as landslides to World Heritage properties and their buffer zones. Such damage is seen in the pilgrimage routes of the “Sacred Sites and Pilgrimage Routes in the Kii Mountain Range” and in the natural elements of their associated cultural landscapes. The author presents a report on the damage from the East Japan Great Earthquake and other disasters on World Heritage and cultural heritage, and on their increasing occurrence in Japan. A discussion on remedial measures and the need for sustainable protection and management for World Heritage and other significant heritage is included.     

CALENDER

Tsunami run-up heights (R) were predicted by using two different artificial neural network (ANN) methods such as feed forward back propagation (FFBP) and generalised regression neural networks (GRNN). The R records resulting from the ground motions, which occurred between 1900 and 2007, were used during the applications. These records were gathered from three coastal states of the USA, namely California (CA), Oregon (OR) and Washington (WA). First, the earthquake moment magnitude (M _w ), the distance from the earthquake source to the run-up location (D), the latitude of the run-up location (L _x ) and the longitude of the run-up location (L _y ) were used as inputs of each ANN method. In order to evaluate the effects of the L _x and L _y on the R prediction, a second input combination consisting of the M _w and D was used. Each ANN method structured for each input combination was applied to estimate the R of both the separate state and the Western Seaboard. In general, the forecasting performance of the FFBP model that used the M _w , D, L _x and L _y in the input layer was found superior to the other models under the conditions of the used data and model structures.     

Unsolved issues related to thermal-hydraulics in the suppression chamber during Fukushima Daiichi accident progressions

ABSTRACT

On 11 March 2011, the Great East Japan Earthquake and Tsunami hit the Fukushima Daiichi Nuclear Power Station. The Fukushima Daiichi Units 1–3 lost all DC and AC power supplies, which set in motion a chain of events that led to releases of radioactivity to the environment. Since then, TEPCO has made many efforts to investigate the accident progressions and the status of the reactors and containment vessels. However, there still exist several tens of unsolved issues to be investigated for the fully understanding of the accident. In this paper, we introduce the unsolved issues related to thermal-hydraulics in the suppression chamber during the Fukushima Daiichi accident progressions. Especially, in Units 2 and 3, there are possibilities that thermal stratification inside their suppression chambers played an important role. It is important that these phenomena are addressed following both theoretical and experimental approaches as support to severe accident simulations.     

海啸作用下漂浮物行为及对陆上建筑作用力研究

根据实际物理实验,采用ALE（任意拉格朗日欧拉）有限元方法在三维数值波浪水池中模拟了海啸的产生、海啸波的传播,与漂浮物作用以及漂浮物与陆上建筑的撞击。通过将海啸上岸后的波高、与漂浮物的作用力以及漂浮物的速度等数值计算结果与物理实验结果进行对比,验证了ALE流固耦合有限元方法在研究海啸作用下漂浮物行为方面的可行性。在此基础上进一步分析漂浮物在海啸作用下对陆上建筑的作用力。通过计算发现,漂浮物的质量、撞击速度对作用力起决定性作用,而被撞建筑的刚度对作用力的影响并不大。     

重要建筑物抗海啸强风的工程减灾措施探讨

对建筑物受海啸、强风作用的破坏特点与破坏机理进行了分析,提出对沿海地区建筑物选址应进行合理规划布局,强化主体结构设计,限制一般结构构件安全度等防海啸强风灾害的原则和工程减灾措施。研究还认为,对海啸、强风等作用下建筑结构的设计荷载和响应应作进一步的试验和理论分析,用科学的发展观来指导海岸工程的设计与建设。上述思想可为沿海地区大型工程项目建设和防灾减灾提供参考。     

海啸对沿海地区桥梁结构的破坏及抵御对策

桥梁工程是保证国民经济发展的主要交通设施,在抗震救灾中更是具有关键性作用.论述了海啸的成因及其破坏特点,探讨了海啸对桥梁上部结构和下部结构的破坏、海啸与桥梁的共振破坏,提出了桥梁工程抵御海啸袭击的对策.     

基于GIS光滑粒子流体动力学改进方法仿真

为了对沿海城市发生海啸进行有效分析和研究,基于光滑粒子流体动力学(SPH)3D粒子法,提出一种沿海城市爆发海啸的分析工具.首先,通过地理信息系统(GIS)得到的3D位置信息(SHP)和数字高程模型(DEM)来展示地形、海拔和建筑物的外部形态;然后,将地表轮廓定义为STL数据,将STL数据转换为粒子数据;最后,缓解SPH方法中的不可压缩条件,并利用虚拟标记处理边界问题.3D仿真表明,海啸粒子没有渗透入建筑物,在建筑物和地面之间没有间隙,验证了所提方法的有效性和良好效果.     

AN EXPERIMENTAL OBSERVATION OF A SOLITARY WAVE IMPINGE-MENT,RUN-UP AND OVERTOPPING ON A SEAWALL

A sequence of laboratory experiments using solitary waves was performed to model the effect of leading form of three types of tsunamis(a bore,an impinging wave and an overtopping wave)on a seawall on a sloping beach.The wave evolution process,impinging pressure along the seawall surface,total overtopping discharge behind the seawall and the maximum run-up height on the rear slope were measured and compared.Laboratory data were employed to re-examine relevant empirical formulae in the literature.The effect of the presence of the seawall in reducing maximum run-up height using the present setup was briefly discussed.The present data can be used for calibrating numerical and mathematical models.     

导管架海洋平台海啸荷载作用分析

为获得复杂海洋环境下海洋平台受海啸荷载作用的实际情况,本文提出一种计算海啸荷载的方法,即海啸理论.同时利用ADINA软件建立导管架海洋平台有限元模型,并将所计算出的海啸荷载施加到平台上进行受力分析.数值仿真表明:海洋平台在海啸荷载作用下的位移集中在上部支撑和甲板上,甲板上的应力变化主要由水平的海啸荷载和重力共同作用产生,且经过对比可知海啸荷载理论是比较正确的,更加符合实际情况.