岩盐三轴压缩试验方法及数据处理方式的对比研究

Comparison of triaxial compression test and data processing methods for rock salt

在能源地下储存及废弃物地下处置库的设计、施工、运行中,岩盐的强度和变形特征是极为重要的参数。正确地获得岩盐的强度参数对地下储存库的设计和安全运行具有重要意义。分别选定江苏金坛和湖北江汉岩样作为试验样本,通过三轴压缩试验获得岩盐短期强度和变形的力学参数,比较并总结了以德国为代表的欧美国家与国内试验方法及数据处理方式的异同。同时介绍了德国短期强度试验确定岩盐损伤起始点的方法及其不足,提出了更为精确地确定方法并确定了金坛岩盐损伤起始点。分析发现:对于大变形岩盐,国内测量的强度数据普遍偏高,应采用横截面积修正以及科学应变代替工程应变的度量方式。

Strength and deformation characteristics of rock salt are extremely important parameters for the design, construction and safe operation of underground energy and waste repositories. However, these require accurate measurements of the strength parameters for the concerned rock salt. In this study, samples of rock salt from Jintan in Jiangsu province and Jianghan in Hubei province, respectively, are chosen for triaxial compression tests to locally determine their short-term strength and deformation parameters. This allows a comparison of the Germany test and data processing methods, performed on behalf of the Western countries, and the Chinese test and data processing methods. Based on the German method including its shortcomings for determining the damage boundary of Jintan rock salt which was employed in the German short-term strength test, this paper presents an improved method and calculates the damage boundary for the Jintan rock salt. Comparison between the two test and data processing methods reveals that German experimental measurements yield lower strength parameter values for rock salt with large deformation. Hence the German test and data processing methods, in which the change of the sample cross-section area is considered and the data are secondarily revised by using scientific strain instead of engineering strain.