软弱土层对中欧场地划分影响的比较

COMPARATIVE ANALYSIS OF THE INFLUENCE OF SOFT SOIL LAYER ON SITE CLASSIFICATION BETWEEN CHINESE CODE GB 50011—2001 AND EUROCODE 8

针对场地中存在软弱土层的多种情况,对中、欧场地划分的差异进行比较。通过对一般场地、20 m深度范围内含软弱夹层场地、20 m深度以下含软弱土层场地的剪切波速的计算,依据中国设计规范GB50011—2001、欧洲设计规范Eurocode 8分别进行场地划分。通过比较分析发现,Eurocode 8的场地分类对20 m深度范围内软弱夹层厚度的反应比GB 50011—2001更敏感,对20 m深度以下软弱土层厚度的考虑比GB 50011—2001更细致,建议中国抗震规范应进一步考虑软弱土层的影响,且将计算深度由20 m进一步向下延伸。

For several sites with soft soil layer, the difference of site classification between Chinese code GB 50011--2001 and European code Eurocode 8 is studied in this paper. Firstly, the shear wave velocity of ordinary site, site with soft interlayer within 20 m depth, site with soft soil layer below 20 m depth is computed, and the site classification is classified according to GB 50011--200.1 and Eurocode 8 respectively. Then, the comparative analysis is carried out, it is found that the thickness of soft soil layer is more vulnerable to change site classification of Euroeode 8 than that of GB 50011--2001 for site with soft interlayer within 20 m depth, which is considered more carefully in Euroeode 8 for site with soft soil layer below 20 m depth. It is suggested that the influence of soft soil layer should be further considered in China code, and the calculation depth should be further extended from 20 m.