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1.
珠海（磨刀门）大桥震害预测及对策 总被引：1，自引：0，他引：1
按《公路工程抗震设计规范》（ＴＪＪ００４－８９）对珠海（磨刀门）大桥进行了抗震鉴定，结果表明大桥满足７度抗震设防要求，最后提出了抗震加固及设计新大桥时可供选用的一些措施。 相似文献
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对新疆维吾尔自治区木垒哈萨克自治县人民医院医技楼进行抗震鉴定工作,主要依据《GB50023-2009建筑抗震鉴定标准》开展。通过具体工作说明A类砌体房屋二级抗震鉴定的方法、过程、内容,以便类似工程借鉴。鉴定结果表明,木垒县人民医院医技楼房屋整体连接构造的可靠性和横墙间距不符合一级鉴定要求,因此在第二级鉴定中采用综合抗震能力指数的方法,最终得出该建筑物不满足鉴定标准要求的结论。该建筑物需要加固或采取其他维护措施达到抗震能力标准。 相似文献
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用新标准实施房屋建筑的抗震鉴定 总被引：3，自引：0，他引：3
本文阐述了按新的《建筑抗震鉴定标准》对设防烈度分别由６度和７度上升为了７度和８度的克拉玛依和乌鲁木齐的房屋建筑实施抗震鉴定的方法，结果和社会经济效益。 相似文献
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我国的抗震设防标准及其设计参数取值汪颖富（中国建筑西南设计研究院）一、抗震设防标准我国新的各种结构设计规范和世界一些国家一样，采用了以概率理论为基础的极限状态设计方法￣［１］。国家标准（ＧＢＪ１１－８９）也符合世界公认的抗震设计原则，即“小震不坏，大... 相似文献
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新抗震规范地震动力功率谱模型参数的研究 总被引：18，自引：4，他引：14
根据我国抗震规范《建筑抗震设计规范》（ＧＢＪ１１－８９）将建筑场地分为４类的事实,确定了对应４类建筑场地的过滤Ｇａｕｓｓ白噪声过程功率谱密度函数（Ｋａｎａｉ－Ｔａｊｉｍｉ谱）的参数值,并导出了Ｋａｎａｉ－Ｔａｊｉｍｉ谱的谱强度与最大地面运动加速度均值,地震烈度及地震影响系数最大值的关系。这与我国新抗震规范建设场地类别的划分相协调,便于实际应用。 相似文献
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2020年6月交通运输部发布了新版《公路桥梁抗震设计规范》（JTG/T 2231-01-2020）（简称"《公规》"）。本文比较了现行《铁路工程抗震设计规范》（GB 50111-2006）（2009年版）（以下简称"《铁规》"）与《公规》的抗震设计相关内容,并分别采用两本规范对25m墩高（D类）、35m墩高（C类）和40m墩高（B类）简支梁进行抗震设计,比较二者地震力和配筋设计结果差异。结果表明:《公规》和《铁规》的抗震设计框架和内容基本一致,在具体规定上如E2或罕遇地震设计最大加速度响应值以及桥墩强度和延性验算方法等方面不同;D类桥梁《铁规》地震力明显大于《公规》,C类和B类桥梁《铁规》和《公规》地震力相当;地震力相同时,《铁规》配筋率计算值大于《公规》,因《铁规》配筋设计基于容许应力法,而《公规》基于极限状态法。 相似文献
7.
关于上海市<建筑抗震设计规程>中长周期设计反应谱的讨论 总被引：11，自引：1，他引：10
在上海市地方标准《建筑抗震设计规程》（ＤＢＪ０８－９－９２）及其１９９６年局部修订增补版本中、对上海市类场地建筑结构的地震影响系数进行了特殊规定,并将结构自振 周期延长到１０ｓ,同时给出了三条加速度时程用于时程分析。本文主要针对《建筑抗震设计规程》中有关长周期反应谱部分的规定,根据国内外的研究现状,进行一些探讨,指出所提供的一条人造地震动时程和两条国外加速度记录用于上海市ＩＶ类场地长周期建筑结构的 相似文献
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对沙角Ａ电厂主厂房（一期）进行了抗震鉴定，计算结果表明其抗震能力满足生命线工程的抗震要求，最后提出了一些抗震加固方法。 相似文献
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依据对具有较高微裂纹密度的筑波花岗岩和极低微裂纹密度的花岗斑岩 2种极端的岩石标本、在等应力速率的快速加载 (约 6MPa/min)和蠕变加载 (轴向应力保持在约 95 %破坏强度 ) 2个极端的加载条件下的实验结果 ,讨论了预存微裂纹密度与加载速度对多晶质结晶岩变形破坏过程的影响。实验中利用高速多通道声发射波形数字记录系统 (每秒可记录多达 5 0 0 0个声发射事件的 32通道波形 ) ,获得了岩石标本破坏前微破裂活动的详细时空分布数据。声发射的发生率、震级 -频度关系中的b值及震源的空间分布揭示出岩石变形破坏过程中微破裂活动具有 3个典型阶段 :初期阶段、第 2阶段和成核阶段。尤其是在成核阶段 ,还观测到发生率和b值有大幅度前兆性起伏。一般而言 ,在相同加载条件下预存微破裂密度越高 ,或对同一岩石加载速度越慢 ,对应的断层成核过程就越长 ,因此最终破坏的可预报性也越高。为了进一步探讨微破裂活动的阶段性特征及其物理本质 ,还利用亚临界破裂扩展模型对声发射数据进行了理论分析 相似文献
12.
《地球物理与天体物理流体动力学》2013,107(1-4):355-368
Abstract EDDIES IN MARINE SCIENCE (Edited by A. R. Robinson) Springer-Verlag, 1983, 268 figures, 625 pages. Price: DM 120 (U.S. $49.60). ISBN 3-540-12253-2 THE SOLAR GRANULATION, by R. J. Bray, R. E. Loughhead, and C. J. Durrant, 2nd Ed., Cambridge University Press 1984. xvi + 245 pp. Price: £27.50, $54.50, ISBN 0-521-24714-4. ASTROPHYSICAL JETS. Proceedings of an International Workshop held in Torino, Italy. October 7–9, 1982. Edited by A. Ferrari and A. G. Pacholczyk, D. Reidel Publishing Company, 1983. xvi + 327 pp. Dfl. 110.00 (US. $48.00). ISBN 90-277-1627-7. INTERNAL KINEMATICS AND DYNAMICS OF GALAXIES. IAU Symposium No. 100. Edited by E. Athanassoula. D. Reidel Publishing Company, xiv + 432 pp. 1983. Price: Dfl. 115 (U.S. $49.50) ISBN 90-277-1546-7 HANDBOOK OF PLASMA PHYSICS—BASIC PLASMA PHYSICS 1. Edited by A. A. Galeev and R. N. Sudan. North-Holland Publishing Company 1983. 730 pages. Price: US. $180.75 (Dfl. 425.00). ISBN 0-444-86427-x. NUMERICAL METHODS FOR FLUID DYNAMICS. Edited by K. W. Morton, xiv + 517 pp, Price $55.50 (£30). ISBN 0-12-508360-2. MAGNETIC FIELDS IN ASTROPHYSICS, By Ya. B. Zeldovich, A. A. Ruzmaikin and D. D. Sokoloff. Gordon and Breach Science Publishers, xvi + 365 pp. 1984. Price $60.00. ISBN 0-677-05530-7 (Vol. 3 in “The Fluid Mechanics of Astrophysics and Geophysics” ISSN 0260 4353). 相似文献
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Improved knowledge on overland flow (OF) generation and its dynamics (i.e. spatial and temporal variations) is essential to understand catchment hydrology, a prerequisite for better water resources and soil management. In this study, our main objective was to quantify the dynamics of OF during rainfall events and to assess its main factors of control. The research study was undertaken in an agricultural 23‐ha catchment of a communal pasture in KwaZulu‐Natal (South Africa) experiencing Mediterranean climate and with variations of soil, topography and vegetation conditions. The dynamics of OF was evaluated during three rainfall seasons (2007 to 2010) by using 1 × 1‐m² microplots (n = 15) located at five landscape positions. At each location, a microplot was equipped with an automatic tipping bucket linked to a logger to estimate the delay between the start of the rain and the start of OF [i.e. the time to runoff initiation (TRI)]. Multivariate analysis was applied to the total OF and TRI data and the information on selected environmental factors (rainfall characteristics; soil type; soil clay content, Clay; proportion of the soil surface covered by vegetation, Cov; proportion of the soil surface covered by crusting, Crust; mean slope gradient, S; soil bulk density, ρb; soil water tension at different depths, SWT). The average OF rate over the 3‐year study period varied 2.3‐fold across the catchment (from 15% footslope to 35% backslope), whereas the average TRI varied by a 10.6‐fold factor (between 0.6 min at bottomland and 6.4 min at footslope). TRI temporal variations correlated the most with event duration (r = 0.8) and cumulative amount of rainfall since the onset of the rainy season (r = ?0.47), whereas TRI spatial variations were controlled the most by Crust (?0.97 < r < ?0.77). Ultimately, TRI spatial variations were modelled and mapped in an attempt to model OF dynamics over the entire microcatchment. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Typical pump-and-treat (PAT) optimization problems involve design of pumping schemes, while minimizing cost and meeting a set of constraints. Due to scarcity of information about the hydrogeological system, stochastic modeling approaches can be used to assess tradeoffs between optimality and reliability. Using a stochastic approach, the constrained, single-objective problem may be turned into a multiobjective problem by substituting constraint inequalities with an additional objective function (OF) that accounts for the reliability of the PAT process. In this work, two approaches are analyzed: in one case, the additional OF consists of the probability of failure of a given remediation policy; in another, the OF additional is represented by the recourse, namely the penalty cost induced by the violation of constraints. In order to overcome the overwhelming computational cost required by stochastic simulation, surrogate forms of the OFs are introduced. In the test case under investigation, such functions are estimated by a kriging interpolation of the OF over a series of data points obtained from stochastic simulations of flow and transport, and calibrated against stochastic optimization solutions. The analysis of the two approaches for addressing the tradeoff of cost vs. reliability indicates that recourse accounts not only for the frequency of constraint violations, as the probability of failure does, but also for the intensity with which these occur. Ultimately, the recourse method allows considering less restrictive policies, although these may be highly sensitive to the choice of penalty functions. 相似文献
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Water quality problems are frequently influenced by hydrological processes, particularly in landscapes in which land drainage has been modified. The expansion of agricultural tile drainage in the Northern Great Plains of North America is occurring, yet is controversial due to persistent water quality problems such as eutrophication. Runoff‐generating mechanisms in North American tile‐drained landscapes in vertisolic soils have not been investigated but are important for understanding the impacts of tile drainage on water quantity and quality. This study evaluated the role of climate drivers on the activation of overland (OF) and tile (TF) flow and groundwater flow responses (GWT) on tile‐drained and nontile‐drained farm fields in Southern Manitoba, Canada. The response times of different flow paths (OF, TF, and GWT) were compared for 23 hydrological events (April–September 2015, 2016) to infer dominant runoff generation processes. Runoff responses (all pathways) were more rapid following higher intensity rainfall. Subsurface responses were hastened by wetter antecedent conditions in spring and delayed by the seasonal soil–ice layer. The activation of OF did not differ between the tiled and nontiled fields, suggesting that tile drains do little to reduce the occurrence of OF in this landscape. Rapid vertical preferential flow into tiles via preferential flow pathways was uncommon at our site, and the soil profile instead wet up from the top down. These conclusions have implications for the expansion of tile drainage and the impact of such an expansion on hydrological and biogeochemical processes in agricultural landscapes. 相似文献
16.
A new simulation/optimization modeling approach is presented for addressing uncertain knowledge of aquifer parameters. The Robustness Enhancing Optimizer (REO) couples genetic algorithm and tabu search as optimizers and incorporates aquifer parameter sensitivity analysis to guide multiple-realization optimization. The REO maximizes strategy robustness for a pumping strategy that is optimal for a primary objective function (OF), such as cost. The more robust a strategy, the more likely it is to achieve management goals in the field, even if the physical system differs from the model. The REO is applied to trinitrotoluene and Royal Demolition Explosive plumes at Umatilla Chemical Depot in Oregon to develop robust least cost strategies. The REO efficiently develops robust pumping strategies while maintaining the optimal value of the primary OF-differing from the common situation in which a primary OF value degrades as strategy reliability increases. The REO is especially valuable where data to develop realistic probability density functions (PDFs) or statistically derived realizations are unavailable. Because they require much less field data, REO-developed strategies might not achieve as high a mathematical reliability as strategies developed using many realizations based upon real aquifer parameter PDFs. REO-developed strategies might or might not yield a better OF value in the field. 相似文献
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A total of 16 strong earthquakes with Ms≥7.0 occurred in the world in 2002 according to the determination of the Chinese Seismic Station Network (Table 1 ). The two strongest earthquakes were Sumatra earthquake (Ms7.8, November 2) and Alaska earthquake ( Ms 7.8 November 4) . Fig. 1 is the distribution of strong earthquakes that occurred in 2002. The global seismicity pattern in 2002 was similar to the ones since 1999. The frequency and strength apparently decreased in 2002 compared with the seismicity in 2001. 相似文献
18.
Multi-scale entropy analysis of Mississippi River flow 总被引：4，自引：3，他引：1
Zhongwei Li You-Kuan Zhang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(4):507-512
Multi-scale entropy (MSE) analysis was applied to the long-term (131 years) daily flow rates (Q) of the Mississippi River (MR) to investigate possible change in the complexity of the MR system due to human activities
since 1940s. Unlike traditional entropy-based method that calculates entropy at only one single scale, the MSE analysis provided
entropies over multiple time scales and thus accounts for multi-scale structures embedded in time series. It is found that
the sample entropy (S
E) for Q of the MR and its two components, overland flow (OF) and base flow (BF), generally increase as time scale increases. More
importantly, it is found that there have been entropy decreases in Q, OF, and BF over large time scales. In other words, the MR may have been losing its complexity since 1940s. We explain that
the possible loss in the complexity of the MR system may be due to the major changes in land use and land cover and soil conservation
practices in the MR basin since 1940s. 相似文献
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<正>1SURVEY OF GLOBE SEISMICITYIN 2008 Atotal of 19strong earthquakes withMS≥7.0occurred in the world in2008according to the Chinese Seismic Station Network(Table1).The strongest earthquake was the Wenchuan earthquake withMS8.0on May12,2008(Fig.1).Earthquake frequency was apparently lower and the energy release remarkably attenuated in2008,compared to seismicity in2007.The characteristics of seismicity are as follows: 相似文献