Ninth Laurits Bjerrum Memorial Lecture: "Small is beautiful"—the stiffness of soils at small strains

The purpose of this lecture is to show how field measurements of displacement around foundations and excavations combined with numerical analysis and recent developments in laboratory techniques have together brought about improvements in the understanding of the stiffness properties of a wide range of soils at the low levels of strain often encountered in practice. Key words: excavations, foundations, weak rock, stiff clay, field measurements, strain, yield, laboratory instrumentation, in situ testing.