Rock mass classification


Rock mass classification systems are used for various engineering design and stability analysis. These are based on empirical relations between rock mass parameters and engineering applications, such as tunnels, slopes, foundations, and excavatability. The first rock mass classification system in geotechnical engineering was proposed in 1946 for tunnels with steel set support.

Design methods

In engineering in rock, three design strategies can be distinguished: analytical, empirical, and numerical. Empirical, i.e. rock mass classification, methods are extensively used for feasibility and pre-design studies, and often also for the final design.

Objectives

The objectives of rock mass classifications are :
  1. Identify the most significant parameters influencing the behaviour of a rock mass.
  2. Divide a particular rock mass formulation into groups of similar behaviour – rock mass classes of varying quality.
  3. Provide a basis of understanding the characteristics of each rock mass class
  4. Relate the experience of rock conditions at one site to the conditions and experience encountered at others
  5. Derive quantitative data and guidelines for engineering design
  6. Provide common basis for communication between engineers and geologists

    Benefits

The main benefits of rock mass classifications:
  1. Improving the quality of site investigations by calling for the minimum input data as classification parameters.
  2. Providing quantitative information for design purposes.
  3. Enabling better engineering judgement and more effective communication on a project.
  4. provide a basis for understanding the characteristics of each rock mass

    Rock mass classification systems

Systems for tunneling: Quantitative