软弱地基土上建筑物不均匀震陷机理研究

RESEARCH ON MECHANISM FOR EARTHQUAKE-INDUCED DIFFERENTIAL SETTLEMENT OF BUILDINGS ON SOFT SUBSOIL

从震害现象、理论分析、动三轴仪实验和大型振动台实验等几个方面 ,研究软弱地基土上建筑物不均匀震陷机理。分析结果表明 :建筑物不均匀震陷取决于地震波输入类型、土层类型及建筑物类型 ;一般情况下 ,地震波的不对称性和不规则性对建筑物不均匀震陷起重要作用 ,在土层较均匀和结构较对称时 ,建筑物仍可能出现明显的不均匀震陷 ,这时地震波的不对称性和不规则性起决定作用 ;目前常用的分析方法难以计算出建筑物不均匀震陷 ,无法给出与实际震害现象和实验相一致的结果 ,关键问题是现有土体残余应变势是以等幅谐波实验为基础的 。

The mechanism for the earthquake induced differential settlement of buildings on soft subsoil is analyzed in terms of the post earthquake damage survey, the theoretical calculation, the dynamic triaxial test and the shaking table test etc. The results are shown that the differential settlement of buildings depends on the types of the inputted earthquake waves, the types of the soil layers and buildings. In general case, the asymmetry and irregularity of seismic waves take an important part in the differential settlement of buildings.Although the subsoils and the structure of buildings are comparative uniformly and in symmetry,yet the differential settlement of buildings may still remarkable appear as usual,at the time that the asymmetry and irregularity of seismic waves play a dominant role for the differential settlement of buildings.The common used current analysis methods,which have difficulty in calculating the earthquake induced differential settlement of buildings,are unable to give out the results identical with practical sesimic damages and experimental conclusions.The key to indicate the question is that the current soil residual strain potential was on the basis of the constant amplitude harmonic wave experiment ,which had not considered to the necessary condition for the effects of the asymmetry and irregularity of seismic waves on the development of soil element strain.