THE TRIASSIC ROCKS, WITH PARTICULAR REFERENCE TO PREDICTED AND OBSERVED PERFORMANCE OF SOME MAJOR FOUNDATIONS

An outline of the geology of the Trias in the British Isles is given, together with a description of its depositional environment. The lithology is described and attention is drawn to differences to be expected between materials in basins, shklf areas between basins, and marginal zones. Faulting, weathering and alteration by leaching are discussed. Variation of the Triassic rocks with depth and from place to place is examined in terms of the drained modulus of elasticity, E. For a number of sites, depth profiles of modulus, and other data, are presented; these are related to lithology and weathering which are related in turn to the geology. E values were obtained from laboratory tests, field tests and by back-analysis of observed settlements. In this connexion a settlement calculation procedure is presented. Three major case histories are described: Heysham, where calculated and observed settlements are in agreement; Oldbury, where the observed settlement greatly exceeded that calculated, and Cardiff, whe...