结构震后残余位移研究进展          下载免费PDF全文

刘巴黎  胡进军 《世界地震工程》2020,(3):131-140

结构在强震作用下进入非线性阶段会产生不可恢复的永久位移或残余变形，结构残余位移是震后结构抗震性能和地震损失评估的重要参数，具有重要的理论意义和工程实用价值。为了深入分析残余位移的研究现状，为面向性态抗震设计和抗震韧性评估的地震动强度指标研究提供参考，全面和系统分析了国内外结构残余位移相关文献，介绍了残余位移的定义，重点论述了影响结构残余位移的主要因素，总结归纳了残余位移计算模型、残余位移控制方法及考虑残余位移的抗震性能评估方法，最后讨论了残余位移研究中存在的问题和建议。  相似文献   

移动荷载对桥梁动力响应的影响研究——以开裂预应力混凝土简支梁为例     

谢颖川  高静  刘长玲  刘迪 《震灾防御技术》2020,15(3):510-518

混凝土桥梁在工作过程中会产生裂缝，为分析移动荷载对开裂混凝土桥梁结构刚度的影响，对开裂梁动力响应进行分析。建立简支T梁桥有限元模型，并将移动荷载施加至有限元模型中。根据简支T梁桥破坏横向分布位置和强度的不同，研究不同工况下各梁荷载横向分布及不同移动速度对裂缝扩展宽度的影响。结果表明，数值模拟结果能较好地验证计算模型的准确性；在较大的移动荷载作用下，混凝土开裂，导致结构刚度减小、位移增大；随着移动荷载和速度的增加，开裂时间增加，结构刚度降低，持续时间增加，位移增大，使结构响应呈现明显非线性。  相似文献   

导管架平台拆除过程稳定性及影响因素分析     

孙树峰  吕涛  陈国明  孙久洋  宋玉东  何睿 《海洋工程》2020,38(1):140-146

现有服役海洋平台正逐步走向老龄化,海洋平台拆除成为海洋工程新的经济增长点。针对达到服役年限的导管架平台,基于数值分析方法模拟拆除过程,开展平台在不同拆除阶段和环境载荷等参数下的稳定性及影响规律研究。基于钢结构整体稳定性理论,以导管架平台拆除过程中顶点位移为参考,定义导管架平台拆除作业稳定性指标,提出拆除作业阶段划分方法,通过分析导管架平台在不同影响因素作用下拆除过程稳定性响应,给出拆除作业建议。选取我国南海某4裙12腿进行实例分析,结果表明:主桩腿对导管架平台起决定性承载作用,拆除部分主桩腿后需要引入外部支撑力,以保证拆除作业安全进行;拆除构件越多,来浪方向和环境载荷大小对平台影响越加显著。研究结果可为导管架平台拆除作业提供参考。  相似文献   

复杂载荷作用下立管触地段损伤管道的动力响应     

代云云  周晶  李志刚 《中国海洋大学学报(自然科学版)》2020,(1):145-153

触地段(Touchdown zone, TDZ)是在役钢悬链线立管(Steel catenary riser, SCR)的关键部位,在复杂载荷作用下,极易形成损伤缺陷,其载荷寿命的评估是深海结构工程中的一个关键问题。本文以大型有限元软件ABAQUS为平台,运用损伤管道实体单元与土弹簧阻尼单元相互作用的模型模拟触地段损伤海底管道在复杂载荷作用下的动力响应,数值计算考虑了管-土相互作用过程中的材料非线性、几何非线性以及接触非线性。讨论了单一环向体积损伤位于触地段管道的不同位置时,触地段损伤管道在不同载荷作用下的动力特性及特征点的动力响应。结果表明,管道所受内外压力以及管道提升端的竖向位移载荷会影响结构的自振频率;体积损伤部位的动力响应较完好部位更剧烈;体积损伤的位置和动力载荷频率对管道动力放大系数的影响很大;当动力载荷的激励频率越接近结构基频时,损伤管道的动力响应及动力放大系数越大。  相似文献   

厚碳酸盐岩覆盖区RVSP三维地震勘探应用效果分析     

胡小鹏 《山东国土资源》2020,36(5):38-43

该文以中国南方一厚碳酸盐岩覆盖区的RVSP三维地震勘探实例,对RVSP三维地震勘探观测系统和数据采集参数的确定、地面等效处理和波场分离等关键处理技术及地质效果进行了阐述和分析,说明了RVSP在克服表浅层复杂地质条件及环境条件对资料的影响及提高地震资料的分辨率有其特定的优势,同时也提出了RVSP三维地震在采集和处理过程中的难点。  相似文献   

Self-centering friction spring dampers for seismic resilience     

Wei Wang  Cheng Fang  Yashuo Zhao  Richard Sause  Shuling Hu  James Ricles 《地震工程与结构动力学》2019,48(9):1045-1065

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Effects of wave directionality on extreme response for a long end-anchored floating bridge     

《Applied Ocean Research》2019

Reliable design codes are of great importance when constructing new civil engineering concepts such as floating bridges. Previously only a scarce number of floating bridges have been built in rough wave conditions and only limited knowledge of the extreme environmental conditions and the associated extreme response exists. To form a better design basis an increased understanding of the sensitivity in the structural response towards changes in short-crested sea parameters is needed. Furthermore, acquiring the necessary accuracy in simulated extreme response is often a computationally expensive endeavour and the number of simulations needed is often based on experience. The present study investigates the wave-induced short-term extreme response of a simplified end-anchored floating bridge concept for several wave environments with a return period of 100 years. The study includes convergence of the coefficient of variation for the extreme response for different realization lengths as well as number of realizations. The sensitivity in the structural response towards different main wave directions and spreading exponents is investigated and includes both transverse and vertical displacement response spectra and extreme Von Mises stress in the bridge girder cross-section. The extreme response is based on an accuracy of 2% in the coefficient of variation equivalent to 40 3-h realizations and a low sensitivity in the response is found for natural occurring spreading exponents and for main wave directions within 15° from beam sea.  相似文献   

STUDY ON RELATIONSHIP BETWEEN THE ACTIVITY OF MIYALUO FAULT AND WENCHUAN EARTHQUAKE SEQUENCE     

LI Zhen-yue  WAN Yong-ge  SHENG Shu-zhong 《地震地质》2019,41(1):72-83

Under the background of thrusting stress regime, a large number of strike-slip earthquakes occurred on the Miyaluo Fault during the Wenchuan earthquake sequence process, which is in the southern part of the Longmenshan Fault. In order to find the cause of their occurrence, stress tensors in subregions near the Miyaluo Fault are estimated. The result shows that in both north and south side of the Miyaluo Fault, the direction of principal compressive stress is nearly perpendicular to the Longmenshan Fault, and its dip is nearly horizontal, and the direction of tensile stress is nearly vertical. While in the Miyaluo fault zone, the direction of principal compressive stress is SWW-NEE, and its dip is nearly horizontal, the direction of principal tensile stress is NNW-SSE, also its dip is nearly horizontal. It is consistent with sinistral shear stress state in the Miyaluo fault zone. It was referred that the behavior of Miyaluo Fault during the Wenchuan earthquake sequence process was caused by tearing effect generated from unbalanced forces of two sides of the fault. To understand the rupture mode of the aftershocks in subregions as described above, the total seismic moment tensors are estimated by adding the corresponding component separately of the seismic moment tensor of aftershocks in each region. The result shows the similar trend of total seismic moment tensor components in the north and south side of the Miyaluo Fault(indicating the consistency of rupture mode in the north and south side of the Miyaluo Fault), and most seismic moment tensor components in the south side is higher than that in the north side, especially the compression component perpendicular to Longmenshan Fault and expansion component in the vertical direction. It indicates that thrusting component in the southeast direction in the south side is greater than that in the north side, and the thrusting difference causes the sinistral tearing effect of the Miyaluo Fault. We also find that the sinistral tearing component of the Miyaluo Fault is the same order of magnitude with the thrusting difference of its two sides, which indicates that the tearing effect of Miyaluo Fault can be completely explained by thrusting difference of its two sides. According to the analysis, we put forward the dynamic model of the Miyaluo Fault, which can explain the above phenomenon.  相似文献   

VELOCITY CHARACTRISTICS OF SHANXI AND ADJACENT AREA AND ITS TECTONIC SIGNIFICANCE          下载免费PDF全文

WANG Xia  SONG Mei-qin  ZHENG Yong  AI San-xi 《地震地质》2019,41(1):119-136

In order to acquire a better velocity structure of the crustal and uppermost mantle beneath Shanxi area, we obtain the group and phase velocities of Rayleigh wave of the periods 8s to 50s in Shanxi and adjacent area using ambient seismic noise recorded at 216 broad-band stations. All available vertical-component time series for 2014 have been cross-correlated to yield estimates of empirical Rayleigh wave Green's function. Group and phase velocity dispersion curves for Rayleigh wave are measured for each interstation path by applying frequency-time analysis. It describes finer velocity structure of the crust and upper mantle in Shanxi, which reflects the geological structure characteristics at different depths. The resolution is within 50km and the resolution of part periods can reach 40km.The Rayleigh wave group and phase speed maps at short periods(8~18s and 10~22s)show clear correlations with shallow geological structures. Mountain areas on both sides of Shanxi depression zone show apparent high-velocity anomaly, except for low-velocity anomaly in the Taiyuan Basin, Linfen-Yuncheng Basin and Weihe Basin. Especially, the areas of Youyu County-Pianguan County-Kelan County-Shuozhou City and Jingle County-Lishi District of Lüliang City in Lüliang Mountains, and Yu County-Fuping County-Yi County and Yangcheng County-Licheng County in Taihang Mountains, present higher velocity anomaly. In addition, the velocity is lowest in the Weihe Basin, and the amplitude of low velocity decreases gradually from the south to the north of the basins in Shanxi, which probably is related to the process of gradual stretching and development of the Shanxi rift zone from the southwest to the northeast. The obvious velocity difference across the latitude of 38°N exists at 18~30s period of phase and 24~35s period of group velocity maps, which is probably related to the deep and shallow Moho depth variation in the south and north of Shanxi and the suture zone of ancient blocks including "hard" southern block and "soft" northern block. At the same time, the research result of receiver function reveals that partial melting of the lower crust occurs in the northern Taihang Mountains, while the southern section remains stable(Poisson's ratio is above 0.3 in the northern Taihang Mountains and 0.25~0.26 in the southern section). The phase velocity map at 30~50s period clearly shows NW velocity gradient belt, and the low velocity anomaly in the northeast side may be related to Cenozoic volcanism. Meanwhile, the eastern border of Ordos block is the western faults of central basins in Shanxi depression zone. However, some research results indicate that the above border is Lishi Fault in the surface, inferring that the Ordos block shows a shape of wide in the upper and narrow in the lower part from the surface to deep. The Datong volcanic area at 18~45s period of phase and 24~35s period of group velocity maps shows low velocity of trumpet shape from shallow to deep, related to the upwelling of hot material from lower mantle in the Cenozoic causing a large area of intense magmatic activity. It indicates the more specific upwelling channel of Datong volcanoes simultaneously.  相似文献   

ENVIRONMENTAL RESPONSE OF THE PERMIAN VOLCANISM IN LUCAOGOU FORMATION IN JIMSAR SAG,JUNGGAR BASIN,NORTHWEST CHINA          下载免费PDF全文

QU Chang-sheng  QIU Long-wei  YANG Yong-qiang  YU Kuan-hong  TANG Li-li  WAN Min 《地震地质》2019,41(3):789-802

The lithological features, the types of organic matter and its occurrence and carbon and oxygen isotopic value were clarified by combining core observation, thin slice authentication, X ray diffraction analysis, kerogen type identification and carbon and oxygen isotope analysis. The characteristic of strata, the distribution of volcanoes of Junggar Basin were also taken into consideration. A comprehensive analysis was conducted to evaluate environmental response of volcanism in Lucaogou formation in Jimsar sag. The results show that rocks is a mixed sedimentation of effusive rock and carbonate rocks, volcanic materials is widely developed in Lucaogou formation and origins from the edge of sag or distant source volcano activity. Organic matter is predominantly unstructural algae and asphaltene. The carbon isotopic value of carbonates ranges between 6.8‰ and 9.7‰ with an average of 8.3‰, featured in high positive excursions, while oxygen isotopic value varies from -11.9‰ to -4.3‰ with an average of -6.2‰. During the period of volcanic activity, the volcanic material released high amounts of nutrient to the lake basin, which is beneficial to the algae and other organic organisms. In the poor oxygen and calm water environments, the organic matter is distributed in the laminar algal and the carbon isotope value is high positive drift. During the intermittent period of volcanic activity, the lake level decreased and the lake bottom water changed to the oxygen-enriched environments. The organic matter is locally enriched or dispersed in local layers, and the carbon isotope values decreased slightly. The frequent volcanic activity promoted the organism boom, which lead carbon isotope value to have high positive characteristics and change trends.  相似文献