唐山地区波速比变化特征研究     

王亚茹  宋昭  刘晓丹  郭蕾  王妍  王时  宫猛  王想 《大地测量与地球动力学》2019,39(7):686-690

选取唐山地区2008~2018年震相数据，利用单台多震和达法和多台多震和达法分别计算波速比，结合研究区内的地震活动对波速比的变化特征进行研究。结果显示，多台多震和达法得到的波速比结果较为稳定，而单台多震和达法得到的结果变化幅度大，显示更多细节；唐山地区ML≥4.5地震发生前单台波速比存在不同程度的异常，异常台站的方位与地震具有一定的对应性。  相似文献   

Introspection on improper seismic retrofit of Basilica Santa Maria di Collemaggio after 2009 Italian earthquake     

Gian Paolo Cimellaro  Andrei M. Reinhorn  Alessandro De Stefano 《地震工程与工程振动(英文版)》2011,10(1):153-161

The 2009 L’Aquila, Italy earthquake highlighted the seismic vulnerability of historic masonry building structures due to improper "strengthening" retrofit work that has been done in the last 50 years. Italian seismic standards recommend the use of traditional reinforcement techniques such as replacing the original wooden roof structure with new reinforced concrete (RC) or steel elements, inserting RC tie-beams in the masonry and new RC floors, and using RC jacketing on the shear walls. The L’Aquila earthquake revealed the numerous limitations of these interventions, because they led to increased seismic forces (due to greater additional weight) and to deformation incompatibilities of the incorporated elements with the existing masonry walls. This paper provides a discussion of technical issues pertaining to the seismic retrofit of the Santa Maria di Collemaggio Basilica and in particular, the limitations of the last (2000) retrofit intervention. Considerable damage was caused to the church because of questionable actions and incorrect and improper technical choices.  相似文献   

Effect of near-fault earthquakes with forward directivity on telecommunication towers     

M.Yahyai  B.Rezayibana  E.Mohammadrezapour 《地震工程与工程振动(英文版)》2011,10(2):211-218

In this paper, the effect of pulse-type motions caused by forward directivity that can release huge amounts of energy in a short time period is studied on a telecommunication tower. Since telecommunication towers have longer periods, they are not as affected by seismic forces. Nevertheless, near source earthquakes characterized by high velocity and velocity pulses can change the behavior of these structures. For this reason, a telecommunication tower located near active faults was selected in this study. Considering the probable earthquake magnitude at the site and the distance of the tower from adjacent faults, nine simulated pulses and three near-fault earthquake records with forward directivity are selected and applied to a 3D fi nite element model of the tower. The results of nonlinear dynamic analysis, i.e., displacements and damage in the tower, indicate that the maximum displacement and drift ratio of the tower under the pulses are obviously affected by the ratio of the structure period to pulse period. When this ratio is decreased and close to 1.0, the maximum displacement and drift ratio are sharply increased and cause large displacements in the tower.  相似文献   

Analytical study of performance evaluation for seismic retrofitting of reinforced concrete building using 3D dynamic nonlinear finite element analysis     

Yuichi Sato  Shinichi Kajihara  Yoshio Kaneko 《地震工程与工程振动(英文版)》2011,10(2):291-302

This paper presents three-dimensional fi nite element (FE) analyses of an all-frame model of a three-story reinforced concrete (RC) building damaged in the 1999 Taiwan Chi-Chi Earthquake. Non-structural brick walls of the building acted as a seismic resistant element although their contributions were neglected in the design. Hence, the entire structure of a typical frame was modeled and static and dynamic nonlinear analyses were conducted to evaluate the contributions of the brick walls. However, the results of the analyses were considerably overestimated due to coarse mesh discretizations, which were unavoidable due to limited computer resources. This study corrects the overestimations by modifying (1) the tensile strengths and (2) shear stiffness reduction factors of concrete and brick. The results indicate that brick walls improve frame strength although shear failures are caused in columns shortened by spandrel walls. Then, the effectiveness of three types of seismic retrofi ts is evaluated. The maximum drift of the firstoor is reduced by 89.3%, 94.8%, and 27.5% by Steel-confi ned, Full-RC, and Full-brick models, respectively. Finally, feasibility analyses of models with soils were conducted. The analyses indicated that the soils elongate the natural period of building models although no signifi cant differences were observed.  相似文献   

Characteristics and factors that influenced damage to dams in the M s 8.0 Wenchuan earthquake     

Liping Jing  Haian Liang  Yongqiang Li  Chunhui Liu 《地震工程与工程振动(英文版)》2011,10(3):349-358

Based on raw data from dams damaged in the Wenchuan earthquake, including many that were severely damaged, characteristics and factors that influenced the damage are discussed in this paper. Findings from this study include: severely damaged dams were densely distributed along the seismologic fault; small dams, especially small earth-rock dams, had the most serious damage that was caused by a variety of factors; the most serious damage was caused by seismic waves; damage was aggregated by aftershocks; and the extent of the damage patterns increased with the seismic intensity. Damage patterns varied in different intensity zones and cracking was the most common type of damage. Most of the dams had a good base with relatively high bearing capacity, and the walls of the earth-rock dams were mostly of clay soil. This type of base and body material mitigated some of the damage to dams. Reservoir maintenance and other factors also have a significant impact on the seismic safety of the dam. Finally, some recommendations to reduce seismic damage to dams are proposed.  相似文献   

A fundamental procedure and calculation formula for evaluating gravel liquefaction   总被引：1，自引：0，他引：1  

Xiaoming Yuan  Zhenzhong Cao 《地震工程与工程振动(英文版)》2011,10(3):339-347

Field investigations following the 2008 Ms8.0 Wenchuan earthquake identified 118 liquefaction sites, most of which are underlain by gravelly sediment in the Chengdu Plain and adjacent Mianyang area, in the Sichuan Province. Gravel sediment in the Sichuan province is widely distributed; hence it is necessary to develop a method for prediction and evaluation of gravel liquefaction behavior. Based on liquefaction investigation data and in-situ testing, and with reference to existing procedures for sandy soil liquefaction evaluation, a fundamental procedure for gravel liquefaction evaluation using dynamic penetration tests (DPT) is proposed along with a corresponding model and calculation formula. The procedure contains two stages, i.e., pre-determination and re-determination. Pre-determination excludes impossible liquefiable or non-liquefiable soils, and re-determination explores a DPT-based critical N120 blows calculation model. Pre-determination includes three criteria, i.e., geological age, gravel contents, gravel sediment depths and water tables. The re-determination model consists of five parameters, i.e., DPT reference values, gravel contents, gravel sediment depths, water tables and seismic intensities. A normalization method is used for DPT reference values and an optimization method is used for the gravel sediment depth coefficient and water table coefficient. The gravel liquefaction evaluation method proposed herein is simple and takes most influencing factors on gravel sediment liquefaction into account.  相似文献   

辽宁省强震动台网运行与管理     

李林侗  金震  梁永朵  刘琳婷 《东北地震研究》2011,27(3):56-60

本文介绍了台网的运行维护与管理情况,以及海城、伊通4．3级地震强震记录的获取情况,指出了台网现行维护方式的不足,并提出了相应的改进措施。  相似文献   

浅析黑龙江省防震减灾地方立法与中央立法的调适     

张东凯 《东北地震研究》2011,27(2):75-78

本文从地方立法与中央立法关系的角度,结合《黑龙江省防震减灾条例》修订过程中的一些实际问题,对黑龙江省防震减灾地方立法的定位与发展进行了分析探讨,为黑龙江省防震减灾法制建设完善提供了参考。  相似文献   

基于多比例尺技术的南京市地震应急数据库建设     

徐敬海  韩烨  聂高众  徐徐  朱丹 《世界地震工程》2011,27(2)

为实现不同比例尺地震应急数据的融合与集成,在分析城市地震应急数据库功能的基础上,设计了基于多比例尺空间数据库技术的南京市地震应急数据库框架。论述了其中不同尺度基础地理信息数据的处理、转换方法,以及多比例尺基础地理信息数据的融合建库方法。接着阐述了地震应急专题数据库的设计和与多尺度基础数据的联接。最后通过开发南京市地震突发事件救灾应急平台,展示了多比例尺应急数据库在地震应急平台中的应用。  相似文献   

2010年玉树地震(Ms7.1)地表破裂特征、破裂机制与破裂过程     

潘家伟  李海兵  吴富峣  李宁  郭瑞强  张伟 《岩石学报》2011,27(11):3449-3459

2010年4月14日,青海省玉树地区发生Ms7.1级地震,造成大量人员伤亡和财产损失.地震发生后,我们对地震地表破裂带进行了详细的考察,并对同震位移量进行了精确的测量.根据野外考察和测量的结果,对玉树地震的地表破裂特征、同震位移量及其分布特征进行了分析,并对地震的破裂机制和破裂过程进行了探讨,取得如下认识:(1)玉树地震形成了沿鲜水河断裂带西北段(甘孜-玉树断裂)分布的东、西两条地表破裂带,西段破裂带分布在微观震中附近的隆宝湖拉分盆地中,长约19km;东段破裂带沿扎曲河南岸及巴塘河西岸山坡展布,长度约31km;上述两条破裂带之间存在约15km的地表破裂空区;(2)野外测量获得玉树地震的最大同震位移量为2.3m,位于东段地表破裂带中部郭央烟宋多附近;(3)地表破裂和野外构造地貌特征均反映了发震断层处于走滑伸展环境,断层左旋走滑过程中伴随正断作用;(4)地震波反演结果和地表破裂分布特征表明,玉树地震的破裂过程包括两次子事件,分别在地表形成了隆宝湖破裂带和扎曲河、巴塘河破裂带,隆宝湖及玉树县城西侧的山间谷地是在甘孜-玉树断裂长期活动的破裂带阶区转换拉张过程中形成的两个拉分盆地.  相似文献