2013年4月20日四川省芦山县发生Ms7.0级强烈地震,造成了大量民居建筑的严重破坏甚至倒塌。本文通过对芦山地震中民居建筑的震害调查,系统总结了砖混民居这一量大面广建筑结构的破坏形式和损伤机制。汶川地震后的新建民居在抗震措施方面有较大幅度的提高,比如大多具有抗震构造措施、采用240mm承重墙等,因此整体震害较轻,但是新建居民在建设房屋时,抗震构造措施的布局有很大的随意性,具体表现在平面内布置不足和竖向分布不规则,导致整体约束效果下降,进而结构发生破坏。雅安地区多处于山坡软土地带、建筑物多临近河流,同时民居建筑的基坑开挖普遍较浅,处理不当,在地震过程中出现地基不均匀沉降,基础遭到破坏,并造成上部结构破坏。相比之下,地基得到妥善处理、严格按照抗震规范设计的民居,震害十分轻微。本文建议继续增强对居民的防震减灾宣传,普及民居抗震构造知识,进行民居的实用抗震措施和地基处理方法的研究,并针对各类民居震害情况,研究有效、经济和快速的加固改造技术。
The Ms7.0 strong earthquake hit Lushan county,Sichuan province,on April 20th,2013,which caused serious human casualties and economic loss.Based on the field investigation,this paper systematically summarizes the seismic damage patterns of masonry residential buildings.Learned from Wenchuan earthquake,the seismic measures of local residential buildings have been taken,and most buildings have been constructed as confined masonry structures.This is the major reason that the seismic damage is averagely slighter than that observed in Wenchuan earthquake.However,the position and distribution of the constructional columns are often changed arbitrarily according to the occupant’s request,resulting in insufficient confinement or vertical irregularity.This mitigates the confinement effect,so that some buildings were damaged seriously.The other reason lies upon the ground condition.Once built on a soft field,and if the field is not well treated,non-uniform settlement occurs,which is going to lead the damage to foundation beam and the superstructure consequently.Finally,it is suggested that further instruction on the seismic safety measures,aseismic technology,ground treatment,and effective,economic,and rapid seismic retrofitting methods should be studied and advanced in the future.