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11.
A general method is developed for optimal application of dampers and actuators by installing them at optimal location on seismic-resistant
structures. The study includes development of a statistical criterion, formulation of a general optimization problem and establishment
of a solution procedure. Numerical analysis of the seismic response in time-history of controlled structures is used to verify
the proposed method for optimal device application and to demonstrate the effectiveness of seismic response control with optimal
device location. This study shows that the proposed method for the optimal device application is simple and general, and that
the optimally applied dampers and actuators are very efficient for seismic response reduction. 相似文献
12.
Nonlinear earthquake response analysis and energy calculation for seismic slit shear wall structures
Based on the concept of structural passive control, a new type of slit shear wall, with improved seismic performance when
compared to an ordinary solid shear wall, was proposed by the authors in 1996. The idea has been verified by a series of pseudo-static
and dynamic tests. In this paper a macro numerical model is developed for the wall element and the energy dissipation device.
Then, nonlinear time history analysis is carried out for a 10-story slit shear wall model tested on a shaking table. Furthermore,
the seismic input energy and the individual energy dissipated by the components are calculated by a method based on Newmark-β
assumptions for this shear wall model, and the advantages of this shear wall are further demonstrated by the calculation results
from the viewpoint of energy. Finally, according to the seismic damage criterion on the basis of plastic accumulative energy
and maximum response, the optimal analysis is carried out to select design parameters for the energy dissipation device. 相似文献
13.
14.
丽江大研镇震灾分布和地脉动测量结果之间的相关性 总被引:4,自引:2,他引:4
丽江7.0级地震后,大研镇被毁建筑物的地理分布呈显4条条带,伤亡人员的地理分布和上述条带重合。91个短周期地脉动测点的观测资料表明,分布在上述条带内的大多数测点,其卓越周期大于0.3S;条带外的测点,其卓越周期一般在0.1S左右。作认为卓越周期和烈度异常之间良好的相关性,是因为地脉动卓越周期和地方震的频谱之间存在良好的相关性。 相似文献
15.
基于自平衡力的弹塑性动力反应分析方法 总被引:1,自引:3,他引:1
本文给出了一个基于自平衡力的弹塑性结构动力反应分析的新方法,详细叙述了方法的原理和过程,并对用改进的Takeda滞变模型描述的梁单元框架结构给出了具体的分析方法。这个方法与传统的方法不同,在分析中不必修正结构的刚度矩阵,而代之以计算代表塑性铰变形引起的应力重分布的动力自平衡力,因而大大地节省了计算机时,最后通过算例对本文方法进行了验证。 相似文献
16.
在管地贫硫银金矿床进行了近场源二极激电法的应用研究,获得了三高一低的次级低缓激电异常,即高ηs、R_2、Js,低ρs,表明用次级参数表示的激电弱异常要明显,为增加矿量,提高地质找矿效果起了积极作用。 相似文献
17.
Properties of wave velocity for two types of granitoids at high pressure and temperature and their geological meaning 总被引:1,自引:0,他引:1
Shufeng Yang Hanlin Chen Jishuang Jiang Guoqiang Zhu Hongshen Xie Wei Hou Yueming Zhang Huigang Xu 《中国科学D辑(英文版)》1997,40(5):470-476
The wave velocity for two types of granitoids was measured using the analytic method of full-wave vibration at high pressure
and high temperature. The laws of velocity changes for them differ with the pressure boost and temperature rise, and the velocity
change of S-type is more violent than that of I-type. The “softening point” of compressional wave velocity (V μ) is also revealed
during the measurement for two types of granitoids imitating the pressure and temperature at a certain depth. But the depth
of “softening”, Vp after “softening” and the percentage of Vp’s drop around the “sofrening point” for two types of granitoids are obviously different. The depth of “softening” is 15 km
approximately and Vp after “softening” is 5.62 km/s for S-type granitoid. But for I-type granitoid the depth of “softening” is 26 km approximately
and Vp after “softening” is 6. 08 km/s. Through careful analysis of rock slices after the experiment, it was found that the “softening”
of elastic-wave velocity is caused by the partial melting of granite. Combined with the results of geophysical prospecting,
these results suggest that the low-velocity layers developing in the interior of Earth crust are related to thc partial melting
of different types of granitoids. The formation of the low-velocity layer in the upper-middle Earth crust is closely related
to the development of S-type granitoid, but that in the lower Earth crust is closely related to the development of I-type
granitoid. 相似文献
18.
Kela 2 Gas Field, with high formation pressure (74.35MPa), high pressure coefficient (2.022) and difficulty of potential test and evaluation, is the largest integrated proved dry gas reservoir in China so far and the principal source for West-East Gas Development Project. In order to correctly evaluate the elastic-plastic deformation of rocks caused by the pressure decline during production, some researches, as the experiment on reservoir sensitivity to stress of gas filed with abnormal high pressure, are made. By testing the rock mechanic properties, porosities and permeabilities at different temperature and pressure of 342 core samples from 5 wells in this area, the variations of petro-physical properties at changing pressure are analyzed, and the applicable inspection relationship is concluded. The average productivity curve with the reservoir sensitivity to stress is plotted on the basis of the research, integrated with the field-wide productivity equation. The knowledge lays a foundation for the gas well productivity evaluation in the field and the gas field development plan, and provides effective techniques and measures for basic research on the development of similar gas fields. 相似文献
19.
The main purpose of this study is to model the δ13C values of methane derived from coal by combining kinetic-simulating experiment with the gas chromatography-isotope ratio mass spectrum (GC-IRMS) analysis. The stable carbon isotopic variation of methane in pyrolysates with heating temperature indicates that the assumptions for both a constant kinetic isotope effect (α) and a uniform initial isotopic composition (δ13Co) are impractical for explaining the carbon isotopic fractionation during coalification. For purposes of simplification, two approaches are used in this paper to deal with the heterogeneity of terrestrial organic matter. One is that, assuming a uniform initial isotopic composition (i.e., δ13Ci, o=δ13Co) for all methane-generating precursors in coal, the isotopic variation of methane is fitted by adjusting ΔEa, i (Ea13C, i−Ea12C, i) for each hypothetical reaction. The other is that, assuming a constant kinetic isotope effect during the whole gas formation, that is all ΔEa, i values are identical, the modeling of methane isotopic composition is achieved by changing the 13CH4 generation potential of each reaction (fi, 13C), namely, by adjusting the initial δ13C value (δ13Ci, o) for each methane-generating precursor. Results of the kinetic calculation shows that the two simulating methods can yield a similar result at a geological heating rate of 2 °C/My, which further demonstrates that those natural gases with methane δ13C value being approximately −36‰ are possibly sourced from the upper Triassic coal measure strata in the Northwestern Sichuan Basin. 相似文献
20.
基于RS和GIS的农业土地利用污染分析 总被引:1,自引:0,他引:1
农业已被确认为地表和地下水最主要的非点源污染源,而土地利用方式又是影响非点源污染的关键性因素。大规模的土地利用与开发、化肥与农药用量的增加、规模养殖业的发展、生活垃圾的增加等,这些非点污染源严重威胁水体质量,进而影响到人们的生活。为了更好地预测和控制、管理非点源污染,必须研究其负荷定量化问题。本文从以上几方面入手,讨论了非点源污染与农业土地利用方式之间的关系,利用组件GIS技术,以网格为评价单元,实现非点源污染负荷的定量计算及可视化分析。文章最后以上海市松江区作为研究区域,对该区的污染情况进行了分析。 相似文献