A Large-Scale Shear Apparatus for Rock Discontinuities and Interfaces

Summary

Abstract

Characterizing the shear behavior of rock discontinuities, whether natural, reinforced, or associated with engineered interfaces, is a key issue for the design of rock engineering structures. However, conventional laboratory tests are limited by scale effects and simplified loading conditions.

In this context, the large-scale shear apparatus developed by the Cerema enables testing of large specimens with natural roughness and material heterogeneities under controlled stress conditions. The device also allows the investigation of complex configurations, such as reinforced discontinuities and bonded concrete–rock interfaces.

This paper presents the main characteristics of the apparatus, together with selected experimental studies that illustrate its capabilities. These experimental studies include tests on passive rock bolts and instrumented concrete–rock interfaces using optical fiber and acoustic sensors. These studies highlight the value of large-scale testing for improving the understanding of shear and failure mechanisms at a representative scale.

The apparatus thus represents an essential intermediate tool between laboratory testing and in situ observations, opening up important perspectives for improving mechanical models and design practices in rock mechanics.