摘要
根据四川筠连M_S4.9地震现场震害调查资料,总结震区各类房屋震害特征及典型地震地质震害情况,结合区域地质构造环境、震源机制解和余震序列,初步探讨震害分布特征及破坏机理。研究结果表明,震区多数房屋为砖混结构,其整体破坏情况较砖木和土木结构房屋重;震区地震地质灾害受高差、坡度和岩性影响较强。震害破坏程度较重的主要因素包括:房屋结构不合理、抗震性能低;场地地基软弱或存在临空面,不均匀沉降现象突出;地质构造环境复杂,震害"上、下盘效应"明显;短时间段内地震频发,震害累积效应显著;人文地理环境限制,屋顶蓄水增强荷载不均匀现象。
In this paper,using the on-site investigation data on seismic damage induced by the Junlian M_S4.9 earthquake of January 28,2017,we determine the earthquake hazard characteristics of different buildings and the typical seismo-geological hazards in this region.The distribution and mechanism of earthquake damage are discussed based on the geological structure,focal mechanism,and aftershock sequence.The results indicate that buildings in the quake-hit region are mainly of brick-concrete structure,and their destruction is more serious than the buildings with a masonry-timber or a civil structure.The distribution of seismo-geological hazards is affected by many factors,such as height difference,slope gradient,and lithology.The critical factors that affected the seismic damage in this area are summarized as follows:(1)weak seismic performance and unreasonable building structures in the seismic area;(2)prominent uneven settlement because of the weak foundations and free faces in the epicentral area;(3)complicated geological structure,including the obvious hanging wall/footwall effect of a reverse fault;(4)frequent occurrence of small earthquakes in a short time before the Junlian M_S4.9 earthquake caused remarkable accumulation of earthquake damage and increased the possibility of seismic damage;and(5)restricted by the human geographical environment,water stored on roofs intensified any asymmetric loading of the brick-concrete buildings.
出处
《地震工程学报》
CSCD
北大核心
2017年第A01期202-208,共7页
China Earthquake Engineering Journal
基金
震情跟踪定向工作任务(2016010104)
四川省地震局地震科技专项项目(LY1609)
关键词
筠连4.9级地震
地震烈度
房屋震害
地震地质灾害
致灾因素
Junlian M_S4.9
earthquake
earthquake intensity
earthquake damage of building
seismo-geological hazard
damage-causing factor