Rock Mass Classification of Chalk, a UK Perspective

Investigating the geomechanical engineering behaviour of Chalk is challenging since it is a generally soft rock formation and presents in cases a different behaviour from other competent rocks. Additionally, Chalk is widespread throughout the United Kingdom and other parts of the world. Thus, an in-depth understanding of Chalk is paramount when considered in engineering projects. In this research work, the geomechanical behaviour of Northern Province Chalk is examined. This study mainly involves characterising two significant units of Northern Province Chalk, namely Flamborough and Burnham Chalk, through intensive fieldwork and laboratory testing. Multiple scanline surveys are conducted along the cliffs of Flamborough to characterise the jointed nature of the Chalk. The samples collected are assessed in the lab to determine the physical properties of the intact Chalk. Moreover, the Chalk mass properties are compared to those estimated from empirical classification systems. Finally, the limitations of applying rock mass classification systems to Chalk have also been highlighted.