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赵泽宁, 段伟, 蔡国军, 武猛, 刘松玉. 中国规范CPT砂土液化判别模型的改进与概率形式[J]. 岩土工程学报. DOI: 10.11779/CJGE20240107
引用本文: 赵泽宁, 段伟, 蔡国军, 武猛, 刘松玉. 中国规范CPT砂土液化判别模型的改进与概率形式[J]. 岩土工程学报. DOI: 10.11779/CJGE20240107
Improvement and probabilistic form of the Chinese code’s CPT-based liquefaction evaluation model[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20240107
Citation: Improvement and probabilistic form of the Chinese code’s CPT-based liquefaction evaluation model[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20240107

中国规范CPT砂土液化判别模型的改进与概率形式

Improvement and probabilistic form of the Chinese code’s CPT-based liquefaction evaluation model

  • 摘要: 静力触探(CPT)因其高效可靠等优点被广泛用于评估砂土液化势。目前中国常用的《岩土工程勘察规范》中典型CPT方法(岩规法)在涉及细粒和深层土的液化判别结果方面存在不合理现象,并且结果难以整合到概率风险评估中。本文考虑细粒含量、不确定性和采样偏差的影响,基于贝叶斯加权最大似然估计,建立CPT双曲线概率模型以改进岩规法,并推荐采用PL=15%所对应的临界锥尖阻力表达式作为确定性方法。最后用实际案例验证所提模型的可靠性。结果表明:CPT双曲线模型中的临界锥尖阻力随深度增加逐渐增大并稳定,更能反映土体的动力学特性。模型适用范围更广,可用于深层土和细粒含量较高的土,准确度高于岩规法和国际通用的Robertson和Wride方法。在不确定性较高的场地,概率模型在一定程度上可以作为确定性模型的替代或补充。

     

    Abstract: Cone penetration testing (CPT) is commonly used to evaluate sand liquefaction potential due to its efficient and reliable merits. The typical CPT method Chinese code method shows unreasonable results in fine-grained and deep soils, and the results are difficult to be integrated into probabilistic risk assessments. In this study, a novel CPT hyperbolic probabilistic model is proposed to improve the Chinese code methods based on the Bayesian weighted maximum likelihood estimation by considering the effects of fines content, uncertainties and sampling bias. The critical cone tip resistance corresponding to PL=15% is recommended as the deterministic method. Examples are presented to illustrate the reliability of the proposed method. Results show that the critical cone tip resistance of the CPT hyperbolic model increases with the increase of depth, and tends to be stable gradually, which can better reflect the dynamic characteristics of soil. The model can be applied to deep-depth and high fines content soils, and the performance is better than Chinese code method and widely used Robertson and Wride method. In sites with high uncertainty, probabilistic models can be used as an alternative or supplement to deterministic models.

     

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