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101.
Effect of lithology and structure on seismic response of steep slope in a shaking table test 总被引:4,自引:2,他引:2
Studies on landslides by the 2008 Wenchuan earthquake showed that topography was of great importance in amplifying the seismic shaking, and among other factors, lithology and slope structure controlled the spatial occurrence of slope failures. The present study carried out experiments on four rock slopes with steep angle of 60° by means of a shaking table. The recorded Wenchuan earthquake waves were scaled to excite the model slopes. Measurements from accelerometers installed on free surface of the model slope were analyzed, with much effort on timedomain acceleration responses to horizontal components of seismic shaking. It was found that the amplification factor of peak horizontal acceleration, RPHA, was increasing with elevation of each model slope, though the upper and lower halves of the slope exhibited different increasing patterns. As excitation intensity was increased, the drastic deterioration of the inner structure of each slope caused the sudden increase of RPHA in the upper slope part. In addition, the model simulating the soft rock slope produced the larger RPHA than the model simulating the hard rock slope by a maximum factor of 2.6. The layered model slope also produced the larger RPHA than the homogeneous model slope by a maximum factor of 2.7. The upper half of a slope was influenced more seriously by the effect of lithology, while the lower half was influenced more seriously by the effect of slope structure. 相似文献
102.
103.
2010年4月14日青海玉树地震震动图 总被引:5,自引:1,他引:4
在2010年4月14日07时49分(北京时间)青海省玉树藏族自治州玉树县(33.2°N,96.6°E)7.1级地震发生后,综合考虑震中地区的地质构造背景、活动断裂分布、震源机制结果、震源破裂过程、我国西部的地震动参数经验衰减关系及局部场地效应的影响,用考虑场地效应的震动图快速生成方法,在震后约2小时后得到玉树地震震中地区的震动图,并提供给相关部门使用.结果表明,此次地震的地震烈度特征预测如下:①烈度的展布方向NW-SE向,与玉树断裂的走向一致;②极震区的烈度为Ⅸ度,面积约为300km2;③烈度Ⅸ度区主要位于震中东南方向沿断裂走向近40km和西北方向沿断裂走向15km之间的区域;④Ⅸ度区的西北端由于局部场地条件的影响,其烈度由基岩参考面的Ⅸ度区降为土层上的Ⅷ度区;⑤Ⅷ度区面积约为3000km2;⑥Ⅶ度区的面积约为8000km2;⑦Ⅵ度区面积约为24000km2. 相似文献
104.
INTRODUCTIONSeismicintensity measurestheintensityof anearthquake exerts onthe groundina certainarea .Itrepresents the averaged measurement of intensity of ground shakingin a certain scope and reflects theperception of peopleinearthquakes as well asthe areal andzonal distributions of earthquakeimpact onground buildings . The“Chinese Earthquake Intensity Scale”(Institute of Engineering Mechanics ,Chinese Academy of Sciences , 1980) describes one by one the correlative relations of huma… 相似文献
105.
Revisiting the response of western North Pacific tropical cyclone intensity change to vertical wind shear in different directions 下载免费PDF全文
不同方向垂直风切变对热带气旋强度变化的影响存在明显差异,但对热带气旋无维强度变化的影响却差异较小.研究发现不同方向垂直风切变对无维强度变化的影响的细微差异与热带气旋周围的高层西风槽,倒槽,低层季风槽等天气系统配置有关.这一结果表明,在研究不同方向切变对热带气旋强度变化的影响时,除了下垫面热力作用外,还应考虑与切变相关的天气尺度系统的热,动力作用. 相似文献
106.
基于历史震例数据,通过对不同烈度的人员死亡率的分析发现,人员死亡率与地震烈度存在着正相关关系,即人员死亡率随烈度的增加而增大,不同烈度的人员死亡率有各自的分布区间范围,而通过对相邻烈度的人员死亡率的分析发现,相邻烈度人员死亡率存在着1个数量级的倍数关系,一般在10倍左右,在低烈度区域,倍数关系集中于偏向大于10倍的区间范围;在高烈度区域,倍数关系集中于小于10倍的区间范围。在此结果上,基于地震烈度、震级等因素构建了烈度人员死亡率模型,决定系数R2值为0.8667,拟合结果相对较好,能够为后续基于分烈度人员死亡率的地震人员死亡评估模型提供参考。 相似文献
107.
2010年1月,中国地震局启动国家地震烈度速报与预警工程项目立项建议书编制工作,2015年经国务院常务会议同意后获批,历经可行性研究、初步设计等,于2018年启动项目建设,并计划2023年投入运行,开展试服务。随着项目的实施,在台站观测系统建设、中心建设与集成、定制化软件研发、服务系统建设与拓展等方面取得重要进展。本文结合预警工程的目标、主要内容、技术体系等情况,对预警工程进展进行了介绍,随着项目的建设,部分地区已经开始对外开展地震预警试服务工作,工程完成后将成为我国防震减灾事业核心业务系统。 相似文献
108.
《地震研究进展(英文)》2022,2(4):100168
Based on the the large shaking table test results on irregular section subway station structure in soft soil, an overall time-history numerical simulation is conducted to study the nonlinear dynamic interaction of the soil-irregular underground structure. Typical test results, including the acceleration of the soil, acceleration, and deformation of the structure, were analyzed. Satisfactory consistency between the simulation and test results is verified, and the difference between these results was discussed in detail. The maximum inter-story drift ratio was approximately 1/472 under input PGA = 0.54 g. The strain responses of columns were significantly larger than those of the side walls and slabs. The components in the lower layers of the irregular subway station structure, particularly in the central columns, underwent cumulative damage. The research results could provide a simplified analysis method to quantitatively evaluate the damage of irregular underground structures in soft soil. 相似文献
109.
William A. Pizer 《Climate Policy》2013,13(4):455-462
Abstract While most of the world has pursued absolute emission limits for greenhouse gases, the Bush administration has proposed an alternative policy formulation based, among other things, on reducing emissions intensity—that is, emissions per dollar of real gross domestic product (GDP). Critics of this formulation have denounced the general idea of an intensity-based emission target, along with its voluntary nature and modest targets. This raises the question of whether intensity-based emission limits, distinct from the other features of the Bush initiative, offer a useful alternative to absolute emission limits. This essay makes the case that they do, based on how emission targets are framed. The argument draws on four key observations: greenhouse gas emissions will continue to rise over the near term; absolute targets emphasize zero or declining emissions growth while intensity targets do not; developing countries' economic development is integrally tied to emissions growth for the foreseeable future; and intensity targets need not be any more complicated to administer than absolute targets. 相似文献
110.