土壤界限含水率标准物质研制

赵秀峰; 高孝礼; 曹磊; 曹景洋; 路新成

doi:10.15898/j.cnki.11-2131/td.202008280119

摘要: 界限含水率是细粒土定名分类、评价土的工程性质的重要依据，也是黏土矿勘查和工业利用的重要评价指标。不准确的界限含水率测试结果将可能导致严重的工程安全事故，造成人身和经济财产损失。标准物质是保障分析数据准确、可比和有效的重要手段，但当前国内外尚无土壤界限含水率标准物质，可见研制土壤界限含水率标准物质具有重要的现实意义。基于以上原因，本文严格按照《一级标准物质技术规范》(JJF 1006-1994)和《标准物质定值的通用原则及统计学原理》(JJF 1343-2012)等规范和标准，研制了5个土壤界限含水率标准物质(GBW07969、GBW07970、GBW07971、GBW07972、GBW07973)。候选物样品分别采自安徽淮北、山西大同及江苏南京等地，经人工粗碎、烘干、灭菌等加工处理后，采用大型球磨机将候选物样品细碎至粒径小于0.25mm。混匀、分装后每个候选物随机抽取25瓶进行均匀性检验，F_实测值均小于临界值F_0.05(24，25)=1.96，相对标准偏差(RSD)介于1.16%~2.67%之间，表明均匀性良好。12个月的考察期内进行的5次长期稳定性检验和考虑两种极端环境温度(60℃、-20℃)的短期稳定性检验，均未发现统计学意义的明显变化，候选物样品稳定性良好。经9家实验室采用2种经典土壤界限含水率测试方法联合定值，10mm液限、塑限和塑性指数3个定值指标的标准值分别介于26.3%~39.9%、16.3%~22.2%、10.0%~17.7%之间，梯度系列显著，涵盖了粉质黏土和黏土两种黏性土类别。该系列标准物质可用于仪器设备校准、质量监控、能力验证等技术质量活动，为水工环地质勘查、岩土工程勘察、黏土矿勘查等工作对土壤界限含水率测试数据准确性的要求提供了保障。

Abstract:

BACKGROUNDSoil limit water content is an important basis for fine-grained soil classification and engineering property evaluation. Additionally, it is an important evaluation index for clay exploration and industrial utilization. Inaccurate test results of soil limit water content may lead to serious engineering safety accidents and personal and economic property losses. Certified reference materials (CRMs) are important for ensuring the accuracy, comparability, and effectiveness of the analyzed data. However, no certified reference materials for soil limit water content exist; therefore, the preparation of CRMs for the soil limit water content holds great significance.

OBJECTIVESTo prepare CRMs of soil limit water content.

METHODSIn strict accordance with the specifications and standards, such as "Technical Specifications for First-Class Reference Materials" (JJF 1006-1994) and "General Principles and Statistical Principles for the Valuation of Reference Materials" (JJF 1343-2012), five standard materials of soil limit water content (GBW07969, GBW07970, GBW07971, GBW07972, and GBW07973) have been developed. These samples were collected from Huaibei of Anhui province, Datong of Shanxi province, and Nanjing of Jiangsu province. After artificial crushing, drying, and sterilization, the samples were finely crushed to less than 0.25mm by a large ball mill. After particle size analysis, the samples were bottled and numbered in a clean room.

RESULTSTwenty-five bottles of each sample were randomly selected for homogeneity testing. All the measured values of F were less than F_0.05 (24, 25)=1.96, and the relative standard deviation (RSD) was between 1.16% and 2.67%, which indicated good uniformity. There were no significant differences in the long-term stability test (12months) and the short-term stability test (60℃, -20℃). The certified values of 10mm liquid limit, plastic limit, and plasticity index were 26.3%-39.9%, 16.9%-22.2%, and 10.0%-17.7%, respectively. The gradient series was significant, which included silty clayey and clayey type of soils.

CONCLUSIONSFive first classes of National CRMs (GBW07969, GBW07970, GBW07971, GBW07972, and GBW07973) of soil limit water content were successfully prepared. This series of CRMs can be used for calibration of instruments and equipment, quality control, capability verification, and other technical quality activities, which provide a guarantee for the accuracy requirements of soil limit water test data in hydraulic environment geological exploration, geotechnical engineering exploration, clay mine exploration, and other related disciplines.

土壤界限含水率标准物质研制

Preparation of Certified Reference Materials for Soil Limit Water Content