基于静力触探试验的液化判别新方法

A new method for evaluating liquefaction based on cone penetration test

近来地震液化灾害频发,再次成为研究重点,发展具有良好应用前景的基于静力触探试验(CPT)的液化判别方法对预防液化灾害具有重要意义。以Boulanger数据库171组数据为回归样本,分析既有方法存在的问题,提出了基于CPT液化判别的双曲线模型和计算公式,并通过提取2011年新西兰地震147组液化新数据,对该方法进行对比检验。研究表明,我国岩土工程勘察规范的CPT液化判别方法对浅埋砂层偏于保守,对深层土又明显偏于危险,而国际上具有代表性的Robertson方法,其液化临界线存在低烈度区不合理回弯、高烈度区又偏于保守的问题。提出的新公式在不同地震动强度和砂层埋深下均可给出合理判别结果,克服了国内外既有方法的缺点,并纳入到具有样板规范性质的《建筑工程抗震性态设计通则》修订稿中,可为我国相关规范修订和工程应用提供支持。

In recent years,seismic damage caused by sand liquefaction occurred frequently in earthquakes.Sand liquefaction has become the focus of earthquake engineering.It is of great significance to develop a method for evaluating liquefaction based on the cone penetration test(CPT)with good application prospects to prevent liquefaction damage.This paper tests the CPT liquefaction evaluation methods through the collected 171 sets of liquefaction data of 15 earthquakes,and analyzes the problems of these evaluation methods,and proposes a new liquefaction evaluation formula of hyperbolic model based on data regression optimization.Extracting 147 sets of liquefaction data of the 2011 New Zealand earthquake to test the new formula,the results show that the new formula has a high and balanced discriminant success rate for different seismic intensities and buried depth of sand,and also overcomes the disadvantages in the existing liquefaction evaluation methods.The new formula proposed in this paper has been adopted into the revised content of the latest The General Rule for Performance-based Seismic Design of Buildings and can provide theoretical basis and support for the revision of relevant specification and engineering applications in China in the future.