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Die Gesamthärte besteht aus einem modifizierten Taber-Abnutzungshärtetest, einem Schmidt-Hammer-Härte-test und in der fallweisen Anwendung des Shore-Skleroskops (C2-Typ), wenn das Gestein zu weich ist, um den Schmidt-Hammer zu verwenden. Die Gesamthärte wird wie folgt definiert:

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SYNOPSISConditions encountered by the authors on several projects (tunnel boring, blast hole drilling, and large diameter pile socket drilling) were unanticipated, undetectable, and even difficult to identify even after they had been encountered . These conditions have caused failure of mechanical components, low penetration rates, and remarkably high cutter wear . Coincidentally, all projects had one or more geotechnical conditions in common . The difficulties encountered, however, could not be attributed to geotechnical factors measurable by classical laboratory or field methods . The difficulties were not discernible or predictable by conventional exploration, rock mechanics testing, or analysis, prior to tender .

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