Laboratory investigation of mudrocks

Summary The problems associated with mudrocks are largely controlled by their lithology and degree of compaction, their susceptibility to water (volume change), the high frequency of discontinuities and their anisotropic character. It is in ground engineering where difficulties are most frequently encountered and for this reason the laboratory investigation is directed towards these issues. Mudrocks are distinguished for these purposes as argillaceous sediments containing more than 500y weight of clastic grains of less than 60 ώm in size. They can range from very strong indurated Palaeozoic mudstones to stiff over-consolidated clays of the Jurassic, Cretaceous and Eocene sequences. Because the spectrum of types is so wide, the laboratory investigation is considered as a testing programme which is itself determined by known mudrock behaviour. In this way the rationale behind the test modules is developed under the following sectional titles: I. index tests and classification; II. bearing capacity and settlement; II. physical effects of water; IV. mineral changes and porewater chemistry; V. stability of slopes; VI. mine and tunnel considerations. Attention is drawn to specific references (and standards) in which details of advocated laboratory tests and methods may be found.