ABSTRACT
Rock mass classification is one of an engineers most widely used tools for predicting the response of a large scale rock mass to an engineering structure. Classification schemes have two main aims. The first deals with quantifying the actual properties of the rock mass. The second looks at design by considering the loading condition, or environment, acting on the rock mass and predicting its resulting behaviour. This chapter only considers the quantifying of rock mass properties. There are three general categories used to assess rock mass properties. These categories are intact rock strength, intact block size and geometry and joint surface condition. Among the categories used to describe rock mass properties, joint condition is generally the least well defined and difficult to quantify. The chapter outlines a procedure which can be followed which would remove some of the subjectivity from joint descriptions.
