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1.
汶川地震后绵竹、都江堰市房屋震害调查与分析 总被引：1，自引：0，他引：1
依据笔者在四川省绵竹市、都江堰市参加建设部组织的汶川地震震后房屋应急评估所取得的资料,对该次地震造成的建筑结构破坏进行了分析,从砖砌体结构、混凝土框架结构、构造问题以及设计与施工缺陷4个方面,论述了各种破坏的形态与成因,讨论了现行设计方法中存在的问题,提出了相应的改进建议。主要结论有：砌体结构的底层墙体强度不足、开间过大、形体复杂是导致其破坏的重要原因,在设计中,应适当提高砌体结构底层墙体的强度,控制房屋的开间,加强形体变化部位;砌体结构的窗下墙应作为连接墙肢的连梁考虑,可以将其设计成抗震设防的第一道防线;框架结构设计中,应考虑框架与填充墙的相互作用,考虑楼梯斜梁或斜板参与结构的整体受力;在现行规范要求的基础上,要适当增加框架柱的截面,节点附近的箍筋应采用焊接封闭箍或螺旋箍;应加强非结构构件的连接与锚固;对乡村房屋建设应予以监管,杜绝结构体系不明确的房屋出现。 相似文献
2.
遥感技术应用于地震研究中的一个重要方面是利用遥感图像的宏观性解译地震活动的构造背景。该项目主要利用遥感及GIS地理信息软件合成数字遥感图像并利用数字高程模型DEM生成三维地貌影像图，与城市房屋等数字图层叠加，建立与地理图层相连的属性数据库，实现断层与地面建筑关系的实时查询，并对用于构造背景的三维立体模型的显示、可视化飞行技术进行初步研究，以期在城市活断层研究中得到应用。 相似文献
3.
近半个世纪以来,钻孔法地应力测量中尚未解决的主要问题是:假定岩石在力学性质上各向同性;没有考虑钻孔效应;忽视了测量的时间效应;简化了岩石力学性质的多变性。由于这些问题的存在,使得主应力测值的误差可达100%,主应力方向的测量误差可达90°,还可以引起主应力性质的正负变换。要进行高水平的地应力测量,必须把测量建立在岩石方学性质各向异性的基础上,减少或避开钻孔效应的影响,考虑或避开测量的时间效应,避开岩石力学性质多变性的影响,分别测量各种地应力成份,进行定点长期连续观测。 相似文献
4.
根据目前地震科普防震知识宣传工作存在的现实问题，认为，要想切实搞好此项工作，并能深入持久地开展下去，使之卓有成效，首先应在地震管理体系中制定出明确的责任目标，并要有保证目标实现的措施，第二在此基础上尽快将此项工作纳入社会宣传的总体规划，实现社会化管理，组织起社会多种宣传力量，齐抓共管。 相似文献
5.
J. F. Macqueen 《Advances in water resources》1980,3(4):165-172
The cooling water discharged from a power station may contain dissolved material, in addition to the heat rejected from the station turbines, which must be dispersed away from the power station in a manner which is environmentally acceptable. Mathematical methods are presented for use in the calculation of the rises in background concentration arising from the discharge of such material into lakes, rivers, estuaries or the sea. The calculations take account of factors including the replacement of the receiving water by freshwater, the available volume of water in the system, the rate at which the material may be degraded in the receiving water and some aspects of the design of the cooling water system. Particular calculations emphasize the different levels of concentration which may be expected from similar discharges into the different types of receiving water body. These examples suggest that for conditions representative of some present power station sites the concentration in a lake may be ten times that in an estuary, and that in an estuary may be ten times that in the sea. Of course, this is not a general result and the concentration level must be calculated for each particular case. The analyses also suggest what hydrographic factors must be measured during field surveys at a particular site if the mathematical methods presented here are to be used for the calculation of concentrations of any discharged material. 相似文献
6.
The development of chloride sensors which can be used for continuous, on‐line monitoring of groundwater could be very valuable in the management of our coastal water resources. However, sensor stability, drift, and durability all need to be addressed in order for the sensors to be used in continuous application. This study looks at the development of a simple, inexpensive chloride electrode, and evaluates its performance under continuous use, both in the laboratory and in a field test in a monitoring well. The results from the study showed a consistent response to changing chloride concentrations over longer periods. The signal was seen to be stable, with regular drift in both laboratory and field test. In the field application, the sensor signal was corrected for drift, and errors were observed to be under 7% of that of conductivity measurements. The study also found that the chloride sensor remained responsive even at low chloride concentrations, where the conductivity electrode was no longer responding to changing chloride levels. With the results, it is believed that the simple chloride sensor could be used for continuous monitoring of groundwater quality. 相似文献
7.
AN EXPERIMENTAL STUDY ON WAVE VELOCITIES IN ROCKS FROM THE YANHUAI BASIN AND ITS GEOLOGICAL IMPLICATIONS 总被引：1，自引：0，他引：1 
下载免费PDF全文
下载免费PDF全文 依据延怀盆地深部的地温地压条件，用模拟实验方法测定了该区代表性岩石的纵波和横波速度以及石英、角闪石在一定深度相变引起的波速变化，提出在中地壳同时具备低速高导的物质可能不是含石英多的岩石而可能是含水矿物多的岩石；讨论了研究区的地壳组成，认为上地壳的上部可能是由泥质灰岩一类的岩石组成，下部可能是由花岗闪长岩一类的岩石组成，没有低速高导层的地区可能是由花岗闪长岩和石英岩等组成，有低速高导层的地区可能由角闪岩相的岩石组成，下地壳可能由角闪片麻岩、中长麻粒岩、辉石麻粒岩等组成 相似文献
8.
R. M. W. Musson 《Bulletin of Earthquake Engineering》2009,7(3):575-589
It might be thought that an empirical ground motion prediction model has only to describe the variations in the input data
set as accurately as possible in order to be useful, with the proviso that the data set is reasonably extensive and well-selected.
If the model is to be used in probabilistic seismic hazard assessment, however, the model will probably be subject to extrapolation
beyond the parameter space within which it was constructed, especially for hazard at low annual probabilities. In this case,
features of the model, especially its functional form, may turn out to have unexpected and undesirable implications. The end
result can be conclusions about the hazard that are clearly not in accordance with commonsense. In this study, two test cases
are used to examine the application of some recent ground motion models to probabilistic hazard studies. Problems are found
that suggest that, although a ground motion model may be a correct representation of its data set, the effects of the functional
form applied can be such that it becomes doubtful whether the model should be used for probabilistic hazard purposes. 相似文献
9.
四分量钻孔应变观测资料的换算和使用 总被引：6，自引：0，他引：6
水平四分量钻孔应变仪观测的是地表附近一点的水平应变变化. 但是其直接记录并非应变变化,应根据互检条件先进行实地相对标定(计算元件校正系数),然后用理论固体潮进行实地绝对标定(计算探头校正系数),才能进行应变换算,给出可作为应变变化使用的数据. 因为钻孔应变仪观测的是应变变化,所以实地标定和应变换算都需要用增量. 对于精确的研究,这些校正系数都可能随时间变化,因而需要根据具体问题按特定时间段对校正系数进行计算. 该文比较系统地说明了四分量钻孔应变观测资料换算和使用的基本步骤和具体方法,并以姑咱台的观测资料为例,给出了具体分析结果. 相似文献
10.
In order to ensure conservation of mangroves, genetic diversity in remaining populations must be explored. Both morphological and isozyme analyses were used and compared in investigating the intra- and inter-estuarine variation in Avicennia marina in Sydney, the most urbanised area in Australia. Sediment characteristics, metal levels, tree attributes, leaf morphology and isozyme/allozyme analyses were conducted. Tree characteristics did not prove to be adequate genetic markers, but leaf morphology may be of use in this species. Isozyme/allozyme analyses indicated that genetic distance corresponded with geographic distance, although habitat metal levels may indicate local selection pressures. High levels of heterozygote deficiencies were displayed in each estuary, which could threaten future viability. The results hold implications for management as periodic isozyme analysis may be useful in indicating management needs. The identification of metal-tolerant types may also be useful. Transplantation among estuaries may assist in increasing genetic diversity, if considered desirable. Whatever the management aims, isozyme/allozyme analyses are shown to be useful for revealing genetic diversity in this species. 相似文献
11.
第四纪松散沉积物中活断层滑动面的显微构造研究方法 总被引：3，自引：0，他引：3
第四纪松散深积物中的活断层滑动面是重要的古地震遗迹，也是鉴定古地震事件和确定古地震时代的重要标志。以往，以第四纪松散沉积物中活断层滑动面主要借助宏观观察进行研究，但遇到了一些难以解决的问题，如隐性断层问题。作者利用显微构造分析，找到了研究这些问题的途径，其方法是对第四纪松散沉积物进行定向原状样品采集，通过室内样品固结，显微薄片制作和显微构造现象观察等，从显微域里研究各种变形现象。用此方法，可以在没有宏观资料支持的情况下确定断面的运动性质；发现并描述第四纪松散沉积物中的隐性断层，研究断层的尖来机制，还可以对工程建设场地发现的不同松散沉积物相接触的现象进行活断层鉴别。 相似文献
12.
本文结合杭州干部培训中心继续教育的实践,探讨了继续教育中开发科技人员创造力的途径。指出科技人员的继续教育要正确处理好传授知识和培养科研能力的关系,着眼于能力的培养。培训内容要注重先进性和实用性,注意学科间的交叉渗透。培训方法要采用有利于激发学员创造性思维的形式,在继续教育中建立起新型的创造教育的观念。 相似文献
13.
Environmental indicators are being increasingly used to emphasise the relevance of monitoring. However, indicators must also be effective. In particular, they must be able to answer management questions, be accessible to the target audience and be sufficiently precise. Here, we use a time series of mercury levels in plaice from Liverpool Bay to illustrate how specific management questions can be formulated, answered, and the precision of these answers assessed. We also show how a programme design can incorporate a series of management questions that are likely to arise over time in response to observed changes in a time series. 相似文献
14.
用于势场反演的特殊解法 总被引：1，自引：0，他引：1
本文以无旋场的积分路径为射线，以边界上已知的势值为输入、输出量、利用反拉东变换求一个梯度场的势函数，用反演的方法求解可以化为拉普拉斯方程的一类二阶偏微分方程。其思路新颖，原理独特，运算正确，边界条件处理方便，数值实现容易，在重力场和地电场的研究中可能得到应用。 相似文献
15.
Capillary column gas chromatography (GC) is extremely useful in investigations of subsurface contamination by petroleum hydrocarbons. Fluid samples collected from observation wells are evaluated by GC methods to detect and analyze petroleum hydrocarbons in dissolved and liquid phases. The presence, types and concentrations of many petroleum-derived hydrocarbons dissolved in ground water can be determined. GC analysis can also be used to determine the composition of liquid hydrocarbon products, including gasoline, distillates and heavier oils. The degree of degradation of sampled liquid hydrocarbon product can be estimated from GC information, and this information can be helpful in estimating the length of time the product has been in the subsurface. Determination of the hydrocarbon source and migration path can be made from GC analysis of fluid samples collected at two or more locations.
This paper is intended to demonstrate interpretative techniques that can be used by hydrogeologists to facilitate the detection, identification and mitigation of subsurface hydrocarbons. 相似文献
This paper is intended to demonstrate interpretative techniques that can be used by hydrogeologists to facilitate the detection, identification and mitigation of subsurface hydrocarbons. 相似文献
16.
While finite-difference methods have been used extensively for many years to model wave propagation in elastic media, some of the more subtle effects observable in such models are very inadequately documented in the geophysical literature, especially in regard to their practical numerical consequences. In addition to the intended travelling waves, and the undesirable exponential instability revealed by the von Neumann test, typical second-order-time finite-difference equations also support drifting linear solutions, as can be verified, both theoretically and by numerical experiment. The necessity of these solutions, and their relationship to the incompleteness of the set of travelling-wave eigenfunctions of the finite-difference operator, can be exposed by a matrix-based analysis, and exact expressions for them can be obtained by using standard algebraic techniques. A further peculiarity of the finite-difference formulation is numerical anisotropy, which emerges in a grid of more than one spatial dimension, even when the modelled medium is intended to be isotropic. This anisotropy can be explained and quantified in terms of the exact eigenfunction solutions to the finite-difference equation, which, it is found, can be obtained in a simple, closed form, for a typical modern 3D staggered scheme. 相似文献
17.
Dr. R. Siksna 《Pure and Applied Geophysics》1961,50(1):23-36
Summary Condensation nuclei detectable in the range of supersaturation used in the expansion method do not play the role expected earlier, for the production of water droplets in natural clouds.However, these nuclei exist in the atmosphere, and they can be of importance in other processes in the air; for example, they can be partners for annihilation of small air ions there. Therefore, a direct investigation of the interaction between the condensation nuclei and the small air ions may be of interest. For this purpose an, ionometric counter for condensation nuclei is designed, in which the air under examination is mixed in a mixing chamber with small air ions produced by a tritium ion-generator, and the presence of condensation nuclei is measured by the decrease of the concentration of air ions recorded with an aspiration ion counter as compared to the concentration recorded when filtered air was originally sucked through the mixing chamber.Comparatively rapid variations of the concentration of nuclei can be continuously recorded. The electrical properties of the aerosol particles destroying air ions can be investigated by inserting an electrical filter. By the ionometric counter condensation nuclei can be investigated without adding water particles to them. 相似文献
18.
Potential for Solute Retardation on Monitoring Well Sand Packs and Its Effect on Purging Requirements for Ground Water Sampling 总被引：1，自引：0，他引：1
Monitoring well sand packs are theoretically capable of retarding metal ions and organic contaminants. If this retardation does indeed occur it may have a significant effect on the purging requirements of newly installed monitoring wells. Calculations based on mass balance and retardation concepts demonstrate that if common guidelines for well purging are followed, contaminants may not be detected or may be detected in lower concentrations than are actually present in the ground water. This problem is greatest in relatively shallow wells installed in low to moderate permeability materials. In most cases, the effect of solute retardation in the sand pack can be avoided simply by additional purging prior to the first sampling of the monitoring well. Common purging guidelines can then be applied to subsequent samplings. The methodology outlined in this paper can be used to calculate the purging requirements of existing monitoring wells or it may be applied to alternative monitoring well designs to test which will require the smallest volume of purged water. 相似文献
19.
The significance of landforms – the contribution of geomorphology to the World Heritage Programme of UNESCO 下载免费PDF全文
下载免费PDF全文 Piotr Migoń 《地球表面变化过程与地形》2014,39(6):836-843
This discussion paper addresses the role of geomorphology in designating UNESCO World Heritage properties. Two of the defined criteria employed in the process are explicitly relevant to geomorphology. Criterion (vii) emphasizes the occurrence of superlative natural phenomena, while criterion (viii) directly refers to landforms and on‐going surface processes, along with historical geological values. Superlative natural phenomena may be singular features, but in recent nominations the focus has tended to be on geomorphic diversity over limited areas. Overall, this is a criterion significantly influenced by subjective judgement. The significance of landforms, as included in the wording of criterion (viii), may be considered in three ways. Landforms may be significant for the science of geomorphology itself, and/or for other natural science disciplines, particularly biology and ecology, and/or be of wider cultural significance, including for history, architecture, general landscape aesthetics, art, or religion, underpinning cultural developments. To better determine the conditions to be fulfilled by a property to be considered as geomorphologically significant at the highest global level required for World Heritage listing seems a timely and useful exercise. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
20.
根据临界加速地震矩释放模型的基本原理,根据研究目的的不同,采取两种不同的方式进行基于网格的并行处理,即按时间分解和按空间分解.如果要根据历史地震目录资料预测某地区未来的地震活动,可以采用空间分解的方式;如果要根据某地区历史上特定时间段的地震活动情况来检验地震加速破裂模型,则可以采用时间分解的方式.最终,能够在同样计算精... 相似文献