Statistical analysis for the hydrogeological evaluation of the fracture networks in hard rocks     

J. Hofrichter  G. Winkler 《Environmental Geology》2006,49(6):821-827

The hydrogeological effectiveness of fracture sets is determined and evaluated by the fuzzy c-mean and hierarchical clustering. These cluster analyses combine the geological spatial attributes and the hydraulic relevant attributes of fractures. Based on the results of the clustering the fracture set volumes are estimated.  相似文献   

A Review of Studies Dealing with Tree Rings and Rockfall Activity: The Role of Dendrogeomorphology in Natural Hazard Research   总被引：1，自引：0，他引：1  

M. Stoffel 《Natural Hazards》2006,39(1):51-70

Over the last few years, rockfall research has increasingly focused on hazard assessment and risk analysis. Input data on past rockfall activity were gathered from historical archives and lichenometric studies or were obtained through frequency–volume statistics. However, historical records are generally scarce, and lichenometry may only yield data with relatively low resolutions. On forested slopes, in contrast, tree-ring analyses may help, generally providing annual data on past rockfall activity over long periods. It is the purpose of the present literature review to survey the current state of investigations dealing with tree-ring sequences and rockfall activity, with emphasis on the extent to which dendrogeomorphology may contribute to rockfall research. Firstly, a brief introduction describes how dendrogeomorphological methods can contribute to natural hazard research. Secondly, an account is provided of the output of dendrogeomorphological studies investigating frequencies, volumes or spatial distributions of past rockfall activity. The current and potential strengths of dendrogeomorphology are then presented before, finally, the weaknesses of tree rings as natural archives of past rockfall activity are discussed and promising directions for further studies outlined.  相似文献   

Experimental and numerical studies of rock salt strain hardening     

M. Hamami 《Geotechnical and Geological Engineering》2006,24(5):1271-1292

The work presented in this paper comes as part of a research program dealing with the thermomechanical behaviour of rock salt. It aims to study laboratory and in-situ long-term behaviour by means of creep tests with deviator and temperature changes. The laboratory results, using a triaxial multi-stages creep tests, highlighted the strain hardening character of rock salt. Furthermore, the in-situ results, using a borehole dilatometer multi-step creep test, have shown that the drilling is carried out in a weakly stressed pillar. The interpretation of the laboratory results, using the J.LEMAITRE law, did not indicate full agreement with all the test results. As a result a ‘double’ J.LEMAITRE model, which takes into account a double strain hardening variable, has been put forward. The validation of this model on the laboratory creep tests is very satisfactory. Furthermore, the activation energy seems satisfactory to represent the influence of the temperature. The in-situ behaviour modelling is clearly more complex than the modelization based on laboratory tests. In fact, it seems that if the rock salt behaviour is maintained by J.LEMAITRE law, it is necessary to vary with the stress, at least, one of the parameters assumed constant in the basic law.  相似文献   

Documentary Evidence of an Economic Character as a Source for the Study of Meteorological and Hydrological Extremes and their Impacts on Human Activities   总被引：1，自引：0，他引：1  

Rudolf Brázdil  Hubert Valá&#;ek  Kate&#;ina Chromá 《Geografiska Annaler: Series A, Physical Geography》2006,88(2):79-86

This paper deals with documentary evidence of an economic character as a proxy for direct study of meteorological and hydrological extremes. Taxation records and reports of those who administrated domains and estates are described with respect to information about meteorological and hydrological extremes. Based on data from eight domains or estates from Moravia (in the Czech Republic), frequency series of floods and convective storms (including hailstorms) were developed for the period 1650–1849. One example of disastrous weather, which took place on 10 August 1694 in the Pern?tejn domain, is used to demonstrate the potential for such studies of the intensity of extremes and their impact on human activities. The importance of economic evidence in the instrumental period is shown through tax rebate data contingent upon hailstorm damage in Moravia (1896–1906). The benefits of employing documentary economic evidence for historical climatology and the study of the impact of meteorological and hydrological extremes on human activities are discussed.  相似文献   

基于微电子系统（MEMS）加速度地震勘探三分量数字检波器简介   总被引：4，自引：0，他引：4  

张莉解文荣  李秀荣 《中国煤田地质》2006,18(2):57-59

基于微电子机械系统（MEMS）制成的微加速度三分量数字地震检波器。集数据采集、处理及传输功能干一体，在结构模型、工作原理、性能指标控制等方面不同于常规检波器，其信号幅值在低于自然频率范围内没有衰减。因其独特的制造技术，MEMS检波器具有超低噪声，大动态范围和极高的向量保真度性能。  相似文献   

吉林台爆破料应力应变关系的三轴试验研究     

侯新强  张远芳  高盟  慈军  刘红  张之科 《新疆地质》2005,23(2):194-198

通过室内大型三轴实验，研究了吉林台水库爆破料在不同级配下的应力应变关系，得到了在一定击实功下爆破料的最大干密度随细料含量变化的规律，分析了爆破料在不同级配和不同围压下应力与应变的变化规律、轴向应变与体积应变的关系及抗剪强度变化特性．从微观的角度说明了变化规律产生的原因，得出爆破料的抗剪强度随级配的变化而变化的规律．  相似文献   

韧性剪切变形对岩石地球化学行为的制约——以北阿尔金巴什考供韧性剪切带为例   总被引：6，自引：0，他引：6  

戚学祥李海兵  吴才来陈松永 《地质通报》2005,24(3):252-257

韧性剪切变形对岩石地球化学行为的制约一直是地质学家们探讨的课题。本文以构成北阿尔金红柳沟——拉配泉俯冲碰撞杂岩带与北阿尔金地块边界的巴什考供斜向逆冲型韧性剪切带为例，通过对韧性剪切带内花岗岩变形前后不同变形强度构造岩的地球化学组成进行对比，确定等比线斜率，探讨韧性变形对岩石体积和成分变异的影响。计算结果表明，在糜棱岩化过程中，糜棱岩化花岗岩体积亏损21％，花岗质糜棱岩体积亏损31％。质量平衡计算结果和等比线图表明，韧；陛剪切作用导致SiO2，流失量最大，A12O3、K2O及Ba、Rb、Sr等都有不同程度的丢失，显示出较强的活动性，MnO、P2O5、Sc位于等比线上或附近，表现出相对的稳定性。岩石中活动组分的变异是流体渗滤作用引起的，不活动组分的变异是体．积亏损造成的。  相似文献   

绿片岩三轴流变力学特性的研究(Ⅰ):试验结果   总被引：17，自引：4，他引：17  

徐卫亚  杨圣奇  杨松林  谢守益  邵建富  王义锋 《岩土力学》2005,26(4):531-537

为了解锦屏一级水电站坝基绿片岩的流变力学特性，采用岩石全自动流变伺服仪对绿片岩进行了三轴压缩流变试验。基于试验结果，研究了绿片岩在不同围压作用下的轴向应变以及侧向应变随时间的变化规律，讨论了流变特性对岩石应力一应变曲线的影响，探讨了不同应力水平下的轴向以及侧向流变速率变化趋势，分析了不同围压下流变的破裂机制，掌握了绿片岩三轴流变的基本规律，从而为该水电站工程流变数值分析时参数的辨识提供了可靠的依据。  相似文献   

抽水引起的含水层水平应变──地裂缝活动新机理   总被引：13，自引：0，他引：13  

王庆良  刘玉海  陈志新  王文萍 《工程地质学报》2002,10(1):46-50

基于Darcy -Gersevanov广义渗流关系式 ,本文首先导出了单井定流量抽水引起的泰斯承压含水层水平运动和应变解析表达式 ,并据此提出了抽水诱发地裂缝活动的含水层水平应变新机理 ,其主要观点为 :受井栅的约束阻挡作用 ,抽水活动将在含水层内部形成近井径向挤压区和远井径向拉张区两个应变区域 ,随着抽水时间的增长 ,近井径向挤压区将逐渐向外扩展 ;当地裂缝及其下伏断层或裂隙位于抽水活动引起的径向拉张应变区域时 ,地裂缝将出现加速活动 ;反之 ,当地裂缝处于抽水活动引起的径向挤压应变区域时 ,地裂缝活动反而受到抑制。上述地裂缝活动机理通过大同机车工厂现场抽水实验得到了初步证实。  相似文献   

Pseudodynamic tests on rubber base isolators with numerical substructuring of the superstructure and strain‐rate effect compensation     

F. J. Molina  G. Verzeletti  G. Magonette  Ph. Buchet  V. Renda  M. Geradin  A. Parducci  M. Mezzi  A. Pacchiarotti  L. Federici  S. Mascelloni 《地震工程与结构动力学》2002,31(8):1563-1582

A pseudodynamic testing procedure has been applied by which the seismic response of a base‐isolated building is obtained by using as specimen the isolators, while the superstructure is numerically simulated. The procedure also takes advantage of the continuous pseudodynamic testing capabilities of the ELSA laboratory, which increase the accuracy of the results and reduce the strain‐rate effect of the rubber bearings. A simple proportional correction of the measured forces compensates the remaining strain‐rate effect due to the unrealistic speed of the test. The correction factor is obtained by means of a characterizing test on the specific rubber isolators. The developed method has been successfully applied to the prediction of the seismic response of a base‐isolated four‐storey building submitted to several specified accelerograms. The results for those earthquakes as well as the effects of some changes of the parameters of the system are discussed. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献