季节冻土层对房屋地震破坏的影响

Influence of Seasonally Frozen Ground on the Seismic Damages of Buildings

冬期地面形成一坚硬的季节冻结层，从而在一定程度上改变了地基土的动力特性，也就改变了地表层的卓越周期．１９８６年黑龙江省德都地区冬、夏两次地震震害调查发现，冬期地震对较刚性房屋破坏严重，而夏期刚好相反，即相对柔性结构房屋地震破坏严重．通过实地观测与室内分析计算，进一步研究了这一问题．

In winter, a stiff layer of seasonally frozen ground is formed on the upper part of the ground surface. The dynamic properties of foudation soil then change to some extent, so do the brilliant periods of foundations. From the investigation on the seismic damages due to the two earthquakes in the summer and winter of 1986 in Dedu Prefecture, Heilongjiang, it is found that for the winter earthquake, the buildings with more rigidity are damaged more seriously, and for the summer earthquake the characteristics of seismic damages are just the contrary, i.e., the more flexible structures are damaged seriously. This is also supported by analyzing calculation and observation in situ.