Hybrid platform for vibration control of high‐tech equipment in buildings subject to ground motion. Part 1: experiment

This paper presents an experimental study, while a companion paper addresses an analytical study, to explore the possibility of using a hybrid platform to mitigate vibration of a batch of high‐tech equipment installed in a building subject to nearby traffic‐induced ground motion. A three‐storey building model and a hybrid platform model are designed and manufactured. The hybrid platform is mounted on the building floor through passive mounts composed of leaf springs and oil dampers and controlled actively by an electromagnetic actuator with velocity feedback control strategy. The passive mounts are designed in such a way that the stiffness and damping ratio of the platform can be changed. A series of shaking table tests are then performed on the building model without the platform, with the passive platform of different parameters, and with the hybrid platform. The experimental results demonstrate that the hybrid platform is very effective in reducing the velocity response of a batch of high‐tech equipment in the building subject to nearby traffic‐induced ground motion if dynamic properties of the platform and control feedback gain are selected appropriately. Copyright © 2003 John Wiley & Sons, Ltd.     

基于GIS的长江三峡水库诱发地震预测数据库构建

从系统需求分析出发 ,介绍了可视化的长江三峡水库诱发地震预测数据库构建的主要内容及其实施技术路线 ,划分了国内外典型的诱震震例以及长江三峡地区基础地理、诱震地质环境和诱发地震前兆监测等相关基础信息的主要类型 ,确定了各类信息的数据库结构和数据格式。在此基础上 ,对各类基础图形进行数字化处理 ,建立了可视化的图形数据库 ;通过其相关属性信息的录入或转换 ,建立了各类图形相应的属性数据库 ;利用GIS技术 ,对图形数据库及其属性数据库进行了无缝集成 ,实现了图形数据与其相应属性数据间的可视化交互式查询、浏览、管理和分析     

用FPS定量解释法实现三维近似成像的探讨

目的 在激发极化数据解释中，过去常采用原始曲线的特征值法，现介绍一种用FPS定量解释法确定异常体空间位置的三维近似成像方法。方法 用FPS定量解释法确定异常体空间位置的三维近似成像方法。结果 该方法可以较准确的确定异常体的上下左右边界以及异常体在垂直测线方向上的延伸情况。结论 算例表明，这种作图解释成像的方法效果较好，值得推广应用。     

水库诱发地震机制与抗震设防

本文探讨了水库诱发震的机制、水库诱发地震动的特征以及设计地震动的选择，提出了诱发地震设计烈度确定方法和地震反应分析方法的选定原则。     

北京西山侏罗纪煤田矿震与地质灾害的关系

北京西山侏罗纪煤田开采中常产生强烈的破坏性冲击地压，是各煤矿生产中严重的井下安全隐患，成为本市十大工业灾害之一。本文作者在多年的地质灾害调查和对京西煤炭开采历史进行分析的基础上，结合西山地质构造特点提出，冲击地压发生时常伴随明显的矿震，矿震的强度受煤质和煤层顶底板性质、地质构造和区域应力场、煤田开采技术和开采深度等因素制约。破坏性矿震除直接对矿山安全生产和矿工生命造成直接的危害外，还常与采矿有关的矿山塌陷等地质灾害相伴发生，对地面居民地建筑物和居民的生命财产安全构成威胁，认为各井田以保安煤柱（或煤带）为采掘对象的生产活动是促发矿震的主要人为扰动因素，建议在有计划的搬迁地表居民地后规划开采，否则应立即强令禁止。     

渤海海峡潮流底应力与沉积物分布的关系

用数值模型方法计算了渤海海峡区潮流引起的最大和平均底应力,以及相应的活动层厚度的空间分布,并根据沉积物参数计算了沉积物临界起动切应力。计算结果的分析表明 :(1)最大潮流底应力和沉积物临界起动切应力的关系与底质分布之间存在着明显的对应,最大潮流底应力大于临界起动切应力的地方,分布着粗颗粒沉积物,若前者小于后者,对应的是细颗粒沉积物,若两者近于相等,则对应着较细颗粒的沉积物;(2 )在山东半岛北部近岸和渤海海峡的东北角,最大潮流底应力小于或接近于临界起动切应力的量值,而对应的沉积物是粉砂和砂,这一例外可能是由于残留沉积的出露,这一假说需要根据全新世海面上升历史、古水动力环境模拟、渤海海峡沉积环境演化等方面的研究来验证;(3)活动层厚度的分布规律与海底沉积物的分布存在着相关性 :即活动层厚度越大,对应的海底沉积物越粗;活动层厚度越小,对应的沉积物越细。     

Applications Of Electrical And Electromagnetic Methods For Environmental And Geotechnical Investigations

Electrical and electromagnetic methods are powerful tools in environmentaland geotechnical investigations. Techniques developed for deeper applications, such as mining,geothermal and crustal studies, are scaled for shallow targets by moving to higher frequencies,earlier decay times and/or smaller array configurations. Another extremely important factor is dense stationspacing, to reduce spatial aliasing, and high quality data to resolve small features. Hence, new instrumentsare concerned with making continuous or dense measurements with high precision, and interpretationalmethods fast enough to handle large datasets quickly. Continuously measuring electrical and time-domainelectromagnetic systems have been developed for geological mapping in hydrological investigations withone-dimensional inversion routines that are rapid and robust. At a smaller scale an electrical systemis used for archaeology studies with excellent results. Working to and above the upper limits ofthe quasi-static approximation, a very early time electromagnetic system is proving successful at mapping subsurfaceinfrastructure in areas of conductive, clay cover, where ground penetrating radar is ineffective.Induced polarization (IP) and resistivity systems that employ multiplexing techniques, while not continuouslymeasuring, allow for relatively rapid production rates and dense sampling for applications ranging fromlandfill and contaminant characterization studies, to verifying the integrity of engineeredsubsurface structures and monitoring infiltration in the vadose zone.     

Prediction of hidden ore bodies by synthesis of geological, geophysical and geochemical information based on dynamic model in Fenghuangshan ore field, Tongling district, China

Although the Tongling district is one of the most important Cu districts in China, exploration strategies need to be urgently updated to achieve a more predictive method for discovering hidden ore bodies. This paper presents a case study showing how new exploration strategies were developed and successfully used to discover a hidden ore body in the Fenghuangshan ore field of the Tongling district. All previously discovered ore bodies in the Fenghuangshan ore field were Cu skarn deposits located where dilational fault zones cut the contact zone of the Xingwuli granitoid complex. The features of the ores and the related magmatic rocks and hydrothermal alteration suggest that porphyry copper deposits are also likely to be present in the ore field. After assessing spatial controls on ore formation, ore-related indicators numerical simulating the coupled thermal–hydrological–mechanical processes during syn-deformation cooling of the Xingwuli Intrusion were used to choose a target area to the south of the Fenfhuangshan mine. In this target area, we have carried out an exploration program involving mapping, rock chip sampling for Cu in the fractured and altered rocks, and pesu-random triple frequency induced polarization (IP) and the controlled source audio-frequency magnetotellurics (CSAMT) surveys. Synthesis of the data obtained in this program identified a target that was subsequently drilled. This test hole demonstrated the presence of high grade Cu ores typical of both skarn and porphyry copper deposits.     

Transient Modeling of Hyperfiltration Effects

Transient models are needed to analyze time-dependent problems like hyperfiltration associated with head differences across clay barriers. Hyperfiltration (solute-sieving) effects create an increased concentration of natural groundwater solutes outside the clay barrier due to the inward head gradient. The purpose of our model is to predict solute buildup and distribution during hyperfiltration providing a basis for time analysis of solute migration. Required input parameters for the model include membrane properties like reflection coefficient, hydraulic conductivity, and solute concentration on the high-pressure side of the membrane before the onset of steady state, solution flux, and the effluent concentration. Model verification is based on published experimental results. The transient hyperfiltration model presented herein may prove useful in elucidating clay membrane (hyperfiltration) effects in the subsurface, however the sole purpose of this paper is to develop a transient model of hyperfiltration effects and test it by using published experimental data.