Assessment of the seismic effect of insulation on extra-large cryogenic liquid natural gas storage tanks

Insulation is typically used in extra-large double-walled cryogenic storage tanks that are used to store liquid natural gas (LNG). These vessels have been designed with the assumption that the insulation offers negligible structural resistance that might cause structural damage. Observation of the deformation of the insulation in such tanks leads to concern that the insulation may become sufficiently compacted to cause significant load transfer between the inner and outer tank. The inner tank, though protected from most external events by the outer tank, is only designed to contain the liquid gas. It is therefore much more sensitive to seismic effects. In this investigation, simplified and 3D finite element models are used to simulate the interaction effects of the fluid, inner tank, insulation and outer tank. This paper presents an initial analysis of the potential effects of LNG tank insulation under earthquake conditions and assesses the potential for structural damage by comparison of models that do or do not consider the insulation layer. The data reported and statistically sorted include the overturning moment, the base shear, the tank wall stress, and the wave height in the tank. The results show that the insulation layer has certain influence on seismic design of LNG tanks.     

Seismic vulnerability of gas and liquid buried pipelines

Lifelines play a crucial and essential role in human life and in economic development. The resilience of those systems under extreme events as earthquakes is a primary requirement, especially when large amount of toxic and flammable material are transported.In this work, the seismic vulnerability of buried gas and liquid pipelines has been analyzed, starting from a large number of damage data to pipelines collected from post-earthquake reconnaissance reports.Seismic fragility formulations and threshold values for the earthquake intensity with respect to the release of content from different types of pipelines have been derived. The main outcome of the work is therefore a novel seismic assessment tool which is able to cover the needs of industrial risk assessment procedures and land use planning requirements.     

Monitoring the volume and lateral spread of disposed sediments by acoustic methods, Oslo Harbor, Norway

Acoustic equipment, including interferometric sonar and parametric sub-bottom profiler, have been used to determine the volume and lateral spread of dredged sediments disposed in the natural submarine depression in the Bekkelag Basin, inner Oslofjord since the beginning of the Oslo Harbor remediation project in 2006. This natural depression is used as a subaqueous confined disposal facility (CDF). Calculation of the volume of disposed sediments in the CDF is based on elevation change, derived from two high-resolution bathymetric datasets obtained in 2004, i.e. before the onset of the remediation project, and in April 2008. Seismic profiles across the CDF have been used to estimate the settlement of the original seabed, caused by loading-induced dewatering and compaction of the seabed sediments under the disposed masses.Detailed bathymetry and backscatter data demonstrate the lateral spread of disposed sediments within a well-confined area covering ca. 195,000 m². The sea bottom within this area is distinctly softer than the surrounding seabed as shown by very low acoustic backscatter amplitude, signifying a very loose surface character of the disposed sediments. The thickness of the disposed sediments reaches 6 m the deepest part of the original depression. The volume calculation of the disposed sediments in the CDF, based solely on bathymetry data, gives a value of ca. 310,000–320,000 m³. Settlement of the original seabed as a result of loading has been estimated to be 30 cm at 5 m thickness of the disposed sediments. Under the condition that the settlement rate is linearly correlated to the thickness of disposed sediments, the settlement corrected volume of disposed sediments is ca. 330,000–340,000 m³. Presented results demonstrate high accuracy and good reproducibility of acoustic seafloor data, and indicate a great potential of such methods as monitoring tools in environmental projects that involve dredging and subaqueous disposal.     

十三陵地震台观测技术系统优化改造

在北京十三陵地震台建设了一个高度集成的地震观测监控系统，将原来分散的观测项目（如测震、GPS、气氡、气汞、电磁波、地电场等测项），改造为集中到一台服务器管理，在一个监控平台上统一实现了对台站数据的收集、入库、管理、处理、监控等业务；对这些观测项目可以在控制台上直接取数并将数据入库；初步实现了观测数据的收集、数据处理、数据管理、数据监控的软件管理系统，减少了系统维护工作量，方便台站工作人员操控。监控系统的地震前兆数据监管软件系统DataMonitor可准实时监视数据，检查数据的异常和到达情况，并向台站数据管理人员告警；可对数据库数据进行统计，包括数据到达情况统计、缺数统计、数据连续率统计等。该系统还提供多种前兆数据处理方法，实现对前兆数据的各种常规分析处理。     

地面运动最大幅值、到时的差动特性

利用ＳＭＡＲＴ－１台阵３次地震的水平分量加速度记录统计了局部场地上地震动加速度最大幅值、到时的变化特性。统计结果表明：在局部场地上，地震动加速度的最大幅值随土层厚度和测点坐标的变化是显著的，而到时变化仅依赖于测点坐标     

生命线工程抗震可靠性分析

本文对作者在生命线工程抗震可靠性分析的分析准则、单体结构可靠度算法、系统可靠性评估和基于系统可靠性分析的优化设计等诸方面所作的工作进行了综述。     

依法做好地震应急是减轻地震灾害的关键环节

本文结合当前地震形势及地震灾害的突发性、社会性、广泛性，对《破坏性地震应急条例》作了阐述，进而论证了依法搞好地震应急总工作是减轻地震灾害的重要环节。     

用地下水资料探讨渭河盆地及周边地区地震形势

本文用陕、甘、宁、青的地下水前兆观测资料，运用异常系列方法的思路，研究了四省区中强地震的中期前兆指标，并进一步探讨了渭河盆地及周边的地震形势。     

中国核电厂场址地震危险性评定方法

在地震危险性概率方法应用的基础上,本文对影响核电厂场址地震危险性评定值的四个重要因素,诸如工作区潜在震源区的判定、地震活动性的时空非均匀性、地震动衰减关系及其衰减模型进行了讨论和改进,提出了一个核电厂场址地震危险性评定的方法。应用该法可提高核电厂场址地震危险性评定的可靠性和显著的经济效益。文中还讨论了地震构造法对核电厂场址地震危险性评定的应用。最后,应用本文提供的2种方法,对秦山核电厂场址进行了地震危险性评定,选取2种方法中的最大值即为核电厂场址地震危险性的评定值。     

地震灾害经济损失估算与预测方法

本文通过对地震造成的社会环境物理破坏损失以及这种物理破坏导致的经济领域损失的分析，研究了直接经济损失预测方法，给出了地震人员死亡率和直接经济损失率的相关统计关系；并根据两种不同的经济分析模型，提出了地震灾害间接经济损失预测方法：经济计量模式和投入产出方法。