【摘要】 中国液化判别方法形成于20世纪80年代,30年来无实质改进。对于细粒土液化判别方法,1999年土耳其Kocaeli地震和台湾集集地震后,国外研究人员做了大量工作。在前人工作基础上,重点研究细粒土液化判别式和初判条件特征指标。通过回顾唐山、海城地震液化场地细粒土土性特征,结合土耳其Kocaeli地震和台湾集集地震液化数据,详细对比国内外细粒土液化判别方法优缺点。结果表明:1塑性指数不宜作为液化判别式指标;2综合细粒含量与黏粒含量判别液化比单独使用任一指标要更为合理;3中国规范液化判别式对细粒土过于保守,尤其只针对粉土考虑黏粒含量导致更为保守,建议去掉"砂土黏粒含量取3"的规定;4黏粒含量不宜作为初判条件指标;5对细粒土的塑性指数,7度、8度和9度分别不小于10,13和15,可判为不液化土。更多还原

【Abstract】 The methods for estimating soil liquefaction in China were basically established in the 1980 s, and they have not substantially improved thence. Following the 1999 Kocaeli and 1999 Chi-Chi Earthquakes, considerable efforts on liquefaction discrimination methods for fine-grained soils have been done by overseas researchers. Referring to previous studies on fine-grained soil liquefaction, indices in SPT-based formula and prelimilary discrimination criteria are specifically analyzed.Reviewing the soil characteristics of liquefaction data from the 1975 Haicheng, 1976 Tangshan, 1999 Kocaeli and Chi-Chi Earthquakes, the advantages and limitations of the existing liquefaction discrimination methods for fine-grained soils are comparatively analyzed. The results show that:(1) Plasticity index should not be used as an index in SPT-based formula.(2)Applying the combination of fine content and clay content to estimate liquefaction potential is more reliable than using either index alone.(3) Chinese code method is much conservative for fine-grained soils, especially considering clay fraction only for the soils with fine content greater than 50%.(4) Clay content should not be used as an index in prelimilary discrimination criteria.(5) The fine-grained soils with plasticity index not less than 10, 13 and 15 corresponding to seismic intensities 7, 8 and9 respectively will not liquefy.更多还原