基于CPTU状态参数的无黏性土最大剪切模量评价方法

段伟; 蔡国军; 刘松玉

doi:10.3969/j.issn.0258-2724.20170432

基金项目: 国家重点研发计划资助项目（2016YFC0800200）；国家自然科学基金资助项目（41672294）；中央高校基本科研业务费专项资金、江苏省研究生科研与实践创新计划资助项目（KYCX17_0139）

详细信息

作者简介:
段伟（1989—），男，博士研究生，研究方向为现代原位测试技术，E-mail：zbdxdw@163.com

通讯作者:
蔡国军（1977—），男，教授，博士生导师，研究方向为现代原位测试技术，E-mail：focuscai@163.com

中图分类号: V221.3

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被引次数: 16

摘要: 土体最大剪切模量是动力基础设计和地震场地响应分析的重要参数，目前该参数的确定主要来源于室内试验，但室内试验值难以反应现场土层的真实情况，因而采用原位测试技术确定土体最大剪切模量的方法备受关注. 以宿迁-新沂高速公路为工程背景，利用地震波孔压静力触探（SCPTU）对现场场地进行测试，在总结已有的最大剪切模量确定方法研究成果的基础上，以实测剪切波速计算得到的最大剪切模量作为参考值，研究了孔压静力触探（CPTU）测试参数与最大剪切模量之间的关系；基于临界状态土力学理论，研究了联合CPTU测试参数和状态参数与最大剪切模量的关系. 结果表明：最大剪切模量与CPTU测试参数存在良好的相关关系，可通过锥尖阻力和孔压参数来近似估计最大剪切模量值；将状态参数作为孔隙比或孔压参数比的有效代替参数，能够同时考虑围压应力与孔隙比双重因素，所估算的最大剪切模量与参考值基本一致. 因此，CPTU原位状态参数可作为一种新方法来初步评价无黏性土的最大剪切模量.

关键词:

Abstract: The maximum shear modulus of soil is an important parameter for dynamic design of foundations and response analysis of seismic sites. At present, this parameter is mainly determined through laboratory tests, but such tests cannot represent the real situation in the field. Thus, in situ testing technologies have attracted much attention. The Suqian-Xinji Expressway was regarded as the engineering background and seismic piezocone test (SCPTU) was conducted at the site. Based on the summary of research results for existing methods used to determine the maximum shear modulus, the relationship between the piezocone penetration test (CPTU) parameters and the maximum shear modulus was studied in terms of the reference value of the maximum shear modulus calculated using the measured shear wave velocity. The relationship between the joint CPTU parameters, state parameters, and maximum shear modulus was also analysed. The results show a good correlation between the maximum shear modulus and CPTU parameters. The maximum shear modulus value can be approximated by cone tip resistance and pore pressure parameters. The state parameter can serve as an effective alternative parameter for void ratio or pore pressure parameter ratio, and the dual factors of confining pressure and void ratio can be considered simultaneously. The estimated maximum shear modulus is the same as the reference value. Therefore, the in situ state parameters of CPTU can be used as a new method to evaluate the maximum shear modulus of cohesionless soil.

Key words:

层号

名称

深度/m

含水量/%

液限/%

标贯击数N

①

填土

1.0

11.27

31.47

②

粉土

4.8

26.12

29.25

③

粉质砂土

6.0

29.48

28.43

④

砂土

未揭穿

27.72

27.64

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