为了探讨2022年9月5日四川省泸定县6.8级地震震中大量底商多层建筑严重破坏或倒塌。选取代表正反两方面的5栋有代表性的建筑，通过理论基础和模型实验进行震害机理剖析。结果表明：震害主要集中在底层，而底层由混凝土柱和砌体墙混搭而成。横向不开洞的砌体墙约束了结构横向及扭转变形，楼板只沿纵向平动，各构件分担的地震剪力与其纵向抗侧刚度成比例。刚度大的硬脆构件将出现“内力凝聚”，进而达到“变形饱和”，以脆性破坏的方式丧失承重能力，此时上部各层的重力转由横墙承担。如果此时地震还未停止，横墙因在出平面方向失去“扶壁”作用，结构整体将沿纵向触地倒塌。相反，底层的构造如果避免刚度的过大差异，就可显著提升抗震能力。

In September 5, 2022, a M6.8 earthquake occurred in Luding County Sichuan Province. Quite a lot of store-front type buildings damaged or collapsed. Five representative buildings representing both positive and negative aspects were selected to analyze the earthquake damage mechanism through theoretical basis and model experiment. The results show that the earthquake damage is mainly concentrated in the bottom layer, which is composed of concrete column and masonry wall. The masonry wall with no lateral openings restrains the transverse and torsional deformation of the structure, and the floor only transports along the longitudinal direction, and the seismic shear force shared by each member is proportional to its longitudinal lateral stiffness. The rigid and brittle members with large stiffness will appear "internal force condensation", and then reach "deformation saturation", and lose the load-bearing capacity in the way of brittle failure, and the gravity of the upper layers will be borne by the transverse wall. If the earthquake does not stop at this time, the transverse wall will lose the role of "buttress" in the direction of exit plane, and the whole structure will collapse along the longitudinal contact with the ground. On the contrary, if the structure of the bottom layer avoids large differences in stiffness, it can significantly improve the seismic resistance.