Delayed geochemical hazard: Concept, digital model and case study

Delayed Geochemical Hazard (DGH briefly) presents the whole process of a kind of serious ecological and environmental hazard caused by sudden reactivation and sharp release of long-term accumulated pollutant from stable species to active ones in soil or sediment system due to the change of physical-chemical conditions (such as temperature, pH, Eh, moisture, the concentrations of organic matters, etc.) or the decrease of environment capacity. The characteristics of DGH are discussed. The process of a typical DGH can be expressed as a nonlinear polynomial. The points where the derivative functions of the first and second orders of the polynomial reach zero, minimum and maximum are keys for risk assessment and harzard pridication.The process and mechanism of the hazard is due to the transform of pollutant among different species principally. The concepts of "total releasable content of pollutant", TRCP, and "total concentration of active specie", TCAS, are necessarily defined to describe the mechanism of DGH. The possibility of the temporal and spatial propagation is discussed. Case study shows that there exists a transform mechanism of "gradual release" and "chain reaction" among the species of the exchangeable and the bounds to carbonate, iron and manganese oxides and organic matter, thus causing the delayed geochemical hazard.     

Evolutionary aseismic design and retrofit of structures with passive energy dissipation

A new computational framework is developed for the design and retrofit of building structures by considering aseismic design as a complex adaptive process. For the initial phase of the development within this framework, genetic algorithms are employed for the discrete optimization of passively damped structural systems. The passive elements may include metallic plate dampers, viscous fluid dampers and viscoelastic solid dampers. The primary objective is to determine robust designs, including both the non‐linearity of the structural system and the uncertainty of the seismic environment. Within the present paper, this computational design approach is applied to a series of model problems, involving sizing and placement of passive dampers for energy dissipation. In order to facilitate our investigations and provide a baseline for further study, we introduce several simplifications for these initial examples. In particular, we employ deterministic lumped parameter structural models, memoryless fitness function definitions and hypothetical seismic environments. Despite these restrictions, some interesting results are obtained from the simulations and we are able to gain an understanding of the potential for the proposed evolutionary aseismic design methodology. Copyright © 2005 John Wiley & Sons, Ltd.     

吉林海沟金矿矿山地质环境及其恢复治理方法

在对海沟金矿矿山地质环境调查基础上，针对矿区存在着的问题，提出了治理与防范措施，对同类矿山有借鉴作用。     

上海市公共卫生中心空调设计

介绍了上海市公共卫生中心空调通风的设计特点,突出反映在呼吸道传染病区、呼吸道门诊、呼吸道临检、生物安全实验室的系统设计中,并介绍了空调水系统的特殊要求。     

A large landslide on the urban fringe of metropolitan Phoenix, Arizona

A granitic rock avalanche, one of the largest Quaternary landslides in Arizona outside the Grand Canyon with a volume of approximately 5.25 M m³ and a width a little under 0.5 km, ran 1 km from the eastern McDowell Mountains. With lateral levees and pressure ridges, the rock avalanche deposit displays many features found on classic sturzstroms. Failure occurred along a major joint plane paralleling the slope with a dip of 44°, when a major base level lowering event in the Salt River system would have undermined the base of the failed slope, and probably during a period of more moisture than normally available in the present-day arid climate. Failure at the subsurface weathering front highlights the importance of the dramatic permeability change between grussified regolith and relatively fresh bedrock. Rock varnish microlaminations (VMLs) dating, in concert with other geomorphic evidence, suggests that the rock avalanche deposit is slightly older than 500 ka. The rock vanish results also have important implications for sampling strategies designed to use cosmogenic nuclide to date Quaternary landslide deposits. Discovery of a large landslide in close proximity to the extending urban fringe of metropolitan Phoenix argues for a more careful analysis of landslide hazards in the region, especially where rapid development excavates bedrock at the base of steep mountain slopes and where the subsurface weathering front is near the surface.     

The lower marine to lower freshwater Molasse transition in the northern Alpine foreland basin (Oligocene; central Switzerland–south Germany): age and geodynamic implications

The Wilhelmine Alpe section near Immenstadt (Allgäu, south Germany), which represents one of the best continuously exposed outcrops within the northern Alpine foreland basin, has been analyzed for magnetostratigraphic and palynostratigraphic signals. The section comprises the marine-to-terrestrial transition from Lower Marine (UMM) to Lower Freshwater Molasse (USM) sediments. Based on the correlation of the local magnetic pattern with the geomagnetic polarity timescale (GPTS) and palynostratigraphic data, an age of about 31 Ma is suggested for the UMM–USM transition in the Wilhelmine Alpe section. A comparison with coeval magnetostratigraphic sections from central and eastern Switzerland indicates that the regression of the UMM sea along the southern margin of the Molasse basin occurred strongly heterochronously between 31.5 and 30 Ma. The heterochroneity is attributed to the deposition of fan-delta and alluvial fan sediments which document that the overall marine conditions during the UMM were accompanied by strong clastic input derived from the rising Alps. This clastic contribution had a much stronger influence on the depositional pattern than previously thought.     

“青藏高原南部空白区基础地质调查与研究”计划项目新成果、新进展

通过2 0 0 4年度各相关图幅的大力工作,在基础地质、矿产和资源等方面取得了大量实际材料,综合研究区域构造地层格架、青藏高原地质图和青藏高原南部火山岩及其地球动力学意义等,取得重要进展和新认识,在矿产资源、旅游和人文景观等方面也取得重要阶段性成果。     

厦门市海沧区北市花岗岩矿滑坡形成机制及治理设计

厦门市海沧区北市花岗岩矿滑坡发生于2004年10月30日14时。滑坡位于呆场的西端帮顶部的第四系填土和淤泥质土层中，滑体将该区域原设的抗滑桩剪断、拔出、推移，土石迅速越过矿区运输公路，塌落到采场工作面，将正在作业的2名工人和生产设备掩埋。滑坡宽度约60m，最大垂直厚度约14m，总体积约13000m^3。由于滑坡对原有防护体系的破坏，根据滑体调查和极限平衡计算结果，滑坡处于不稳定状态，直接威胁着整个采场设备和未来生产的安全。必须对北市花岗岩矿滑坡进行专项治理。滑坡宜采用治水、削坡减载和支挡相结合的综合治理措施。     

地震灾害预测和应急模拟系统的设计与应用——以永安市城市应急系统为例

城市防震减灾是地震潜在频发区提高自然灾害防治能力建设的重要方面。本文结合福建省永安市城市防震减灾信息管理系统的建设,探讨设计防震减灾数值模型,分析模型集成的关键技术,构建了地震风险评估、建筑物易损性评价、生命与财产损失估算、救援与救灾管理调度等模型和基于GIS开发的震害预测和应急模拟系统。该系统在福建省永安市的实际应用表明,通过对地震灾害预测结果的分析,可加强城市抗震中的薄弱环节,为灾区政府应急响应和制订对策提供决策支持辅助信息,从而显著提高城市防震减灾的综合能力。     

三江并流世界自然遗产地旅游地质景观成景地质作用初步分析

三江并流世界自然遗产地丰富独特的旅游地质景观是多种地质作用与不同成景岩组交互叠加作用的结果。其发育的地层基础主要为碳酸盐成景岩组、变质岩成景岩组、碎屑岩成景岩组以及岩浆岩成景岩组等,典型内力成景地质作用为板块缝合作用、断裂成景作用、变质成景作用,外力作用则主要有河流、冰川、丹霞、地热、喀斯特作用等。