基于美标岩土勘察的土质分类方法研究

Research on Soil Classification Method Based on Geotechnical Survey of American Standard

近年来,随着国家"一带一路"战略计划,越来越多的中国企业走出国门,承担着海外建设工程,美国标准的土分类体系在国际范围内广泛使用。系统介绍了美标体系下USCS、AASHTO和静力触探试验的土工程分类方法,阐述了各方法的具体内容、相互联系及应用特点。以南亚某国勘察项目为具体案例,简述其应用中的情况和若干问题。指出美标体系下USCS是一种应用于工程的土质分类简明方法。与我国标准相比,在粗粒土界限粒径划分、细粒土塑性图、土工试验方法等方面有一定的区别。AASHTO土的分类常用于公路建设中土壤集料等方面,在勘察工作中应用较少,并且与USCS土的分类方法两者之间没有直接的对应关系。采用静力触探进行土层划分和分类本质上还是一个间接的方法,在区域地质资料和工程经验丰富的地区可以直接利用,对于资料和经验缺乏的地区还需要结合钻孔资料进行验证。其研究内容可供以美标进行的海外工程勘察项目予以参考和借鉴。

In recent years,with the national"the Belt and Road"strategic plan,more and more Chinese enterprises are going abroad and are undertaking the overseas construction projects.The soil classification system of American Standard is widely used internationally.The soil engineering classification methods of USCS,AASHTO and static penetration test under the American Standard System are systematically introduced.The specific contents,mutual relations and application characteristics of each method are expounded.Taking a survey project of a country in South Asia as an example,the situation and some problems in the engineering application are briefly described.It is pointed out that USCS under the American Standard System is a concise method applied in the soil classification of the projects.Compared with the Chinese standard,there are some differences in the particle size division of coarse-grained soil,the plasticity diagram of fine-grained soil and the soil engineering test method.AASHTO soil classification is often used in soil aggregate in highway construction,but it is seldom used in survey work,and there is no direct corresponding relationship between AASHTO and USCS soil classification.It is an indirect method to divide and classify the soil layers by the static penetration test in essence.It can be directly used in areas with regional geological data and rich engineering experience.But in the areas with lack of data and experience,it needs to be combined with the drilling data for verification.The study contents can be referred for the overseas engineering survey based on American Standard.