岩石磨蚀性指数分级讨论

隧道施工中,岩石的磨蚀性是影响各类破岩工具磨损的主要因素之一。国际上设计了许多评价岩石磨蚀性的小型试验,其中Cerchar试验因其操作简易性获得了普遍应用,其结果CAI(Cerchar Abrasivity Index)值能够较好地预测破岩工具连续、平稳的正常磨损,目前我国也广泛采用该试验进行岩石磨蚀性评价。由于我国引进该试验时间较晚,尚无国家试验规范,CAI值的等级划分不明确。本文收集了国际上各试验室与机构使用的分级标准,从CAI值分级所用的钢针硬度、CAI值对应的破岩工具磨损量、大量试验数据的分布3个方面综合比较,认为国际岩石力学协会推荐的CAI值分级比较合理。本文对国内Cerchar试验规范创立、岩石磨蚀性评价具有借鉴意义。

Discussions on the Rock Abrasivity Index Classification

Rock abrasivity is one of the main factors affecting the wear of various tools in tunnel construction. Many small scale tests are designed for assessing rock abrasivity in the world. Among of these tests, Cerchar abrasiveness test, due to its ease of operation, has been prevalently used in the world. Its result, CAI (Cerchar Abrasivity Index) value, is capable to predict a normal tool wear which is steady and continuous. At present, the Cerchar test is widely used in China to assess rock abrasiveness. However, as the Cerchar test is lately introduced in China without a national test specifications, and CAI value classification remains unclear. This paper collectes five CAI value classifications used in the international laboratories and institutions. By discussing on hardness of stylus used to determine CAI value, tool wear corresponding to each CAI class and extensive testing results, we think that ISRM suggested CAI classification is the most reasonable one. This paper could be a reference to establish the Cerchar test specifications and evaluate rock abrasiveness in China.