地震液化判别及危害性评价

Determination and Hazard Evaluation of Seismic Liquefaction

摘要:

饱和砂土地震液化有可能诱发极为严重的破坏，已成为土动力学领域的重要研究课题之一。对液化的判别分为初判和复判。初判指根据已有的勘测资料或简单的测试手段，初步判别土层的液化可能。对于初判可能发生地震液化的土层，则再进行复判。鉴于土层液化的影响因素较多，我国规范建议采取经验方法，即标准贯入法，静力触探法，剪切波速法。单一判别方法都有局限性和适用范围，宜用各种方法综合判别。液化危害性评价使用危害性指标，分析液化对建筑物的危害程度。评价方法主要有液化指数法，震陷值法，谱强度比法和综合法。以评价指标为依据，划分液化影响的综合等级，全面反映液化危害程度。

Abstract:

Earthquake liquefaction of saturated sandy soils may induce severe damage，and this issue has become an important research topic in the field of soil dynamics.To judge the potential for earthquake liquefaction and to evaluate liquefaction hazards can lead to better control and prediction of liquefaction.Liquefaction discrimination may be considered first by making a preliminary judgment.Preliminary judgment，according to available survey data or a simple testing method，may provide a determination of the initial level of soil liquefaction.Further discrimination is necessary for soil layers where earthquake liquefaction may occur，as determined by the preliminary judgment.Since there are many factors affecting soil liquefaction，we recommend an empirical method that includes the standard penetration test，the static cone penetration （static sounding）test，and the shear wave velocity method.The single discrimination method has limitations in its scope of application；therefore，a combination of various methods is more reliable.Liquefaction hazard evaluation adopts a harmfulness index to analyze the degree of harm caused to buildings by liquefaction.Evaluation methods mainly include the liquefaction index method，the seismic settlement value method，the spectrum intensity ratio method，and the synthetic method.Based on the evaluation index，a comprehensive liquefaction ranking can fully reflect the potential and extent of the liquefaction hazard.