A distributed parameter model of a frame pin‐supported wall structure

Many reinforced‐concrete frames collapse via a soft‐story mechanism during severe earthquakes. Such collapses are mainly attributed to concentrated deformation in a soft story. Deformation control is thus important in preventing collapse. The frame pin‐supported wall structure is a type of rocking structure that releases constraints at the bottom of the wall. Previous research has obtained good results for the deformation control of this type of structure. However, the interior forces and strength demands of the pin‐supported wall have not been systematically explored. In this paper, a distributed parameter model is developed to investigate the strength demand of the wall in a frame pin‐supported wall structure. In the model, the pin‐supported wall is simplified as a bending beam and the frame is simplified as a shear beam. The two beams are joined by distributed shear connectors, so that the shear force can be transferred at any location on the interface. The model can be solved using differential equations based on equilibrium and compatibility. The accuracy of the model is verified using SAP2000 (Computers and Structures Inc., Berkeley, CA, USA). Displacement distribution of the structure and distributions of the moment and shear force within the pin‐supported wall are obtained for two typical external force profiles. It is found that the pin‐supported wall can effectively reduce the drift concentration factor. Distributions of the displacement, moment, and shear force are closely correlated with the relative stiffness of the wall and frame. Finally, recommendations on the stiffness and strength of a pin‐supported wall are made. Copyright © 2015 John Wiley & Sons, Ltd.     

Evaluation model of landslide hazards induced by the 2008 Wenchuan earthquake using strong motion data

Landslides induced by the 2008 Wenchuan earthquake in the Longmenshan area were relatively well instrumented,which makes it possible to investigate the landslides using ground motion records.Firstly,this paper analyzes the data from Wenchuan earthquake on both regional and local site scale.The analyses show that the Newmark accumulative displacement calculated from the ground motion recorded in a particular geological hazard zone corresponds to the hazard intensity in that zone;the larger the displacemen...     

Adsorption characteristics of copper ion on nanoporous silica

Adsorption by nanoporous media is critically involved in many fundamental geological and geochemical processes including chemical weathering,element migration and enrichment,environmental pollution,etc.Yet,the adsorption behavior of metal ions on nanoporous materials has not been systematically investigated.In this study,MCM-41 material with a monodisperse pore size(4.4 nm)and a large BET specific surface area(839 m^2/g)was hydrothermally prepared and used as a model silica adsorbent to study the adsorption characteristics of Cu^2+as a representative metal ion.The Cu^2+adsorption capacity was found to increase with increasing suspension pH in the range from 3 to 5 and to decrease in the presence of NaNO3.At 25℃,pH=5,and a solid-to-liquid ratio of 5 g/L,the adsorption capacity was determined to be 0.29 mg/g,which can be converted to a dimensionless partition coefficient of 45,indicating a strong enriching effect of nanoporous silica.The adsorption isotherm and kinetic data were fitted to several commonly used thermodynamic,kinetic,and diffusion models.The adsorption mechanism was also studied by Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy and synchrotron-based X-ray absorption spectroscopy.The results suggest that Cu2+ion adsorption is an entropy-driven endothermal process,possibly involving both outer-sphere and inner-sphere complexes.     

An interval-parameter multi-stage stochastic programming model for water resources management under uncertainty

In this study, an interval-parameter multi-stage stochastic linear programming (IMSLP) method has been developed for water resources decision making under uncertainty. The IMSLP is a hybrid methodology of inexact optimization and multi-stage stochastic programming. It has three major advantages in comparison to the other optimization techniques. Firstly, it extends upon the existing multi-stage stochastic programming method by allowing uncertainties expressed as probability density functions and discrete intervals to be effectively incorporated within the optimization framework. Secondly, penalties are exercised with recourse against any infeasibility, which permits in-depth analyses of various policy scenarios that are associated with different levels of economic consequences when the promised water-allocation targets are violated. Thirdly, it cannot only handle uncertainties through constructing a set of scenarios that is representative for the universe of possible outcomes, but also reflect dynamic features of the system conditions through transactions at discrete points in time over the planning horizon. The developed IMSLP method is applied to a hypothetical case study of water resources management. The results are helpful for water resources managers in not only making decisions of water allocation but also gaining insight into the tradeoffs between environmental and economic objectives.     

基于实地调研的中国西南地区不同震级人员死亡数量研究

地震是造成人员死亡最严重的自然灾害之一,震后对人员死亡等灾情的快速评估是地震应急响应和救援的关键。总结经验发现,在地震前进行预评估工作是提高震后灾情快速评估精度和时效性的有效手段。通过对62次发生在我国西南地区的历史震例分析后发现,当地震震级小于4.5级时,基本不会造成人员死亡情况。本研究利用我国云南和四川部分区县的实地调研数据,发现地震人员死亡数与震级存在指数函数关系,由此构建了针对各个区县的地震人员死亡人数指数函数估算模型,并计算了回归系数。基于该模型,获得了5.0～8.0级地震人员死亡数查找表(以0.5级为间隔),用于辅助震后快速评估工作。     

Revisiting Force Model Error Modeling in GRACE Gravity Field Recovery

Surveys in Geophysics - The gravity field recovery from GRACE (Gravity Recovery and Climate Experiment) mission data is contaminated by both observation noise and dynamic force errors, especially...     

基于手机位置数据的地震灾情指标选择

选取四川阿坝州九寨沟县MS7.0地震、新疆博尔塔拉州精河县MS6.6地震、四川广元市青川县MS5.4地震作为案例分析,绘制活跃Wi Fi数量、无线网络联网设备数量、汇总在线设备数量、活跃基站数量等4种地震灾情指标在地震发生前后数量变化的折线图。根据与地震前1天变化情况的对比分析,验证地震灾情指标的可用性,选取出效果好的指标,这对进一步研究震后快速获取极震区位置、影响场方向等具有重要意义。     

地震安全性评价数据的集中管理

本文分析了目前地震安全性评价数据管理的现状和数据集中管理的优势,提出了实现集中管理地震安全性评价数据的技术,以及数据安全防护措施。     

意大利地震紧急事务处置与应急响应系统简介

意大利地震紧急事务处置的特点:①地震灾害与其他灾害统一在一个部门进行紧急事务处置。民防部专门负责实施各类灾害应急救援,应急处置职责范围广泛,包括自然灾害与人为灾害的各类灾害应急救援。健全的组织机构保障了应急处置的高效联动。②地震应急响应技术系统联动集成。硬件平台、基础数据库、软件开发与灾害模型研究4个方面进行集成。③高分辨卫星遥感技术实现灾情快速获取。     

地壳的Q结构与观测结果的解释

本文分析了地壳Q结构对于实测Q值结果的影响。对已发表的大部分实测数据进行分析,结果表明地震波射线路径与Q值显著相关。因此,在对实测的Q值空间分布状况进行解释的时候,不仅要考虑地震波频率的影响,还应对射线路径—距离效应进行分析和校正。本文还按照现有中国大陆地壳速度模型计算了地震射线在水平层状介质中的传播路径及震中距与射线最低点深度的函数关系,给出了华北及西南部分地区地壳Q结构。