Site investigation is indispensable in geotechnical practice, but only a small portion of the soil affected by the intended geotechnical construction is examined and/or tested in the laboratory or in situ, leading to significant uncertainties in site investigation results. The uncertainty in the site investigation results depends greatly on the number of specimens tested (i.e. sample size) during site investigation. In many other areas that involve sampling, such as polls, surveys and quality control, sample sizes are often determined using statistical charts, based on the target levels of accuracy and confidence. However, conventional statistical charts, which only deal with independent data, are seldom used in geotechnical site investigation, because geotechnical properties are usually spatially correlated. No statistical chart with consideration of spatial correlation is available for determining sample sizes in geotechnical site investigation. Existing geotechnical design codes around the world (e.g. Eurocode 7) only provide conceptual principles on sample size determination. This study develops statistical charts for determination of sample size at different levels of both accuracy and confidence for geotechnical site investigation. Real cone penetration test data and real laboratory test data are used to illustrate application of the proposed statistical charts, and the charts are shown to perform well.

中文翻译：

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统计图表，用于确定岩土工程现场调查中各种准确性和可信度级别的样本量

现场调查在岩土工程实践中是必不可少的，但是只有一小部分受预期岩土工程影响的土壤是在实验室或原位进行检查和/或测试的，导致现场调查结果存在很大的不确定性。现场调查结果的不确定性在很大程度上取决于现场调查过程中测试的样本数量（即样本大小）。在许多其他涉及抽样的领域，例如民意测验，调查和质量控制中，常常根据目标的准确性和置信度水平，使用统计图确定样本量。但是，由于岩土属性通常在空间上相关，因此仅在岩土现场调查中很少使用仅处理独立数据的常规统计图。在岩土现场调查中，没有考虑空间相关性的统计图表可用于确定样本大小。全球现有的岩土工程设计规范（例如，欧洲规范7）仅提供了确定样本量的概念性原则。这项研究开发了统计图表，用于确定岩土工程现场调查在不同级别的准确性和置信度下的样本量。实际的锥孔渗透测试数据和实际的实验室测试数据用于说明所建议的统计图的应用，并且显示这些图表现良好。这项研究开发了统计图表，用于确定岩土工程现场调查在不同级别的准确性和置信度下的样本量。实际的锥孔渗透测试数据和实际的实验室测试数据用于说明所建议的统计图的应用，并且显示这些图表现良好。这项研究开发了统计图表，以确定岩土工程现场调查在不同级别的准确性和可信度下的样本量。实际的锥孔渗透测试数据和实际的实验室测试数据用于说明所建议的统计图的应用，并且显示这些图表现良好。