PhD projekt-Study on scale effect on rock mechanical parameters for rock joints

Aim and goal

The need for understanding the risk for sliding in the joints in the basement rock is of importance in the design of deeply located underground spaces. The project aims to contribute with high quality data from tests in a uniquely large scale for the development of models for full scale rock joints.

Challenge

Replicas are castings from rock joints and forms an important part in the research work by that the use of replica allows for repeated tests with the same crack surface. However, the results can be difficult to interpret and occasionally contradictory.

Numerical models are used on basis of laboratory tests to predict the behaviour of full scale rock joints. Tests on different scales yields different results and a challenge is therefore to understand how a scale effect shall be considered in the development of models for full scale rock joints.

Solution

To derive a methodology for the generation of high quality data in the usage of replica and by this create conditions for consistent results. This is done by identification and quantification of critical steps in the manufacturing process of replica.

By the development and usage of a shear test equipment for uniquely large specimens the aim is to derive data that previously has not been accessible for increased understanding of the behaviour of full scale rock joints.

Effect

The data from this project can be used for research for a long time forward. The results will particularly be used in the safety assessment of repositories for nuclear waste in Sweden and Canada.