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以新疆巴楚—伽师Ms6.8级地震液化现场勘察和测试为基础,获取了47个场地的标准贯入试验资料,分析了现有基于标准贯入的砂土液化判别方法的适用性,提出了新的砂土液化判别公式。分析表明国内外现有基于标准贯入击数的砂土液化判别公式不适用于新疆地区,中国现有规范对此次巴楚地震非液化点判别成功率88%,但对液化场地判别成功率仅为38%,会给出明显偏于危险的结果。以新调查数据建立的砂土液化判别模型由地震烈度、实测标准贯入击数、标准贯入击数基准值、地下水位、砂土埋深等5个参数构成,其中标准贯入击数基准值以及地下水位和砂土埋深的影响系数分别采用归一化方法和本文提出的优化方法给出。与中国现有规范相比,新疆巴楚液化土层有所增加,推导出的标准贯入击数基准值远小于现有规范,表明巴楚地区抗液化能力显著低于以往形成我国规范时调查的可液化场地,深层土和低水位砂层液化可能性更大。所建立的砂土液化判别新公式,液化回判成功率为91%,非液化回判成功率为85%,表明构建的模型合理,计算公式可靠,同时新公式延续了中国现有规范的基本形式,工程使用方便,可为新疆地区区域性规范制订提供参考。
Based on the site investigation and testing of liquefaction of Bachu-Jiashi Ms6.8 earthquake in Xinjiang, the standard penetration test data of 47 sites were obtained, and the applicability of existing sand liquefaction determination methods based on standard penetration was analyzed. Proposed a new sand liquefaction discrimination formula. The analysis shows that the existing sand and soil liquefaction criteria based on the standard penetration number are not suitable for Xinjiang region. The success rate of 88% for non-liquefaction point of the Bachu earthquake is estimated by the existing Chinese standard. However, Only 38% will give a clearly biased result. The sand liquefaction discrimination model established with the new survey data is composed of five parameters of seismic intensity, measured standard penetration number, standard penetration strike number, groundwater level and sand depth. Among them, the criterion of standard penetration number And the influence coefficients of groundwater level and sand depth are respectively given by the normalization method and the optimization method proposed in this paper. Compared with the existing Chinese norm, the liquefied soil layer in Bachu of Xinjiang has been increased, and the standard reference value of standard penetration strike is far less than the existing standard, indicating that the anti-liquefaction capability of Bachu area is significantly lower than that of the previous formation of our country’s norm Of the liquefiable site, deep soil and low water level sand is more likely to liquefaction. The established liquefaction judgment new formula, liquefaction success rate of 91%, non-liquefaction success rate of 85%, indicating that the model is reasonable, the formula is reliable, while the new formula continues the basic norms of China Form, project easy to use, can provide a reference for the formulation of regional norms in Xinjiang.