From Mud to Rock and Back – the 23rd Glossop Lecture

Synopsis

As fine-grained muddy sediments, including over-consolidated clays, mudstones and shales underlie large areas of the UK, including major urban areas and infrastructure routes, such mudrocks frequently form the bedrock at construction sites and slope and tunnel engineering works.They may also be used as fill or construction materials.

The compilation of data on the engineering properties of mudrocks from different geological formations demonstrates how lithology and burial history, including the effects of removal of overburden and weathering processes, influence their properties and behaviour.

A review of the performance of mudrocks in engineering situations including slopes, tunnels and in embankment and foundation construction highlights the importance of durability and chemical weathering processes, especially the oxidation of pyrite.Advances in the understanding of the durability properties of mudrocks are also described.

It is argued that understanding controls on the properties of mudrocks underlies ways of avoiding the problems that can arise in civil engineering works involving these materials.It is apparent that there is much to be gained from the publication of case histories of past engineering projects, particularly those in which problems have occurred.