南水北调中线安阳段主要为地面渠道工程，需开挖大量的岩土体。施工过程中揭露出了大量的泥灰岩、砾岩、砂岩等第三系软岩硬土，同前期工作认识出入较大，施工中对岩土界线认识存在一定分歧。通过进一步现场地质调查、点荷载、现场钻进速率测试试验和室内力学、岩石化学、声波试验等，认识了安阳渠段的岩土工程特性。在对比分析已有岩石质量分级和软岩硬土分界的基础上，提出了适用于安阳段岩土体的可挖性工程分级。该分级以岩石单轴抗压强度、纵波波速、净钻进速率、天然容重等为主要指标，将岩土体可挖性施工工程级别划分为9级16个亚级。结果表明，该分级较好地结合了软岩硬土的开挖特性，与对应等级岩土方量计算相结合，较合理地解决了工程造价问题。该分级体系可望为其他第三系岩土地面工程施工分级提供参考。

The canal of Anyang Section in the Middle Route of South-to-North Water Diversion Project needs to excavate a lot of rock and soil. There are lots of Neogene hard soil-soft rocks such as marlite, conglomerate, sandstone etc. It is very different to the preliminary perception and there are quite different understanding of boundary lines between rock and soil. The geotechnical properties were got by field investigation, point load test, drilling test and indoor mechanical and chemical, acoustic tests. The rock and soil excavation classification was made based on rock quality and soft rock-hard soil classifications. Uniaxial compressive strength, longitudinal wave velocity, the net drilling rate and natural bulk density were taken as the indicators and the excavation classification system was composed of 9 classes and 16 sub-classes. The result showed that it gave a good assessment of the different characteristics of rock excavation and gave a reasonable solution to the project cost. The classification system may give a good reference for other similar projects involving Neogene hard soil-soft rocks.