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Session 1: Introduction |
Department of Geology, University of Nottingham, University Park, Nottingham NG7 2RD, UK
Of the several comprehensive geological reviews of the East Midlands, none makes more than a passing reference to the engineering or environmental geology. This paper is thus the first to attempt such a review, although only a brief appraisal is possible here.
Earth tremors causing minor structural damage have occurred in the Nottingham region, although more damaging ground movements have usually resulted from natural subsidence, reactivation of Pleistocene landslips or collapse of old mines for lead ore and gangue minerals, limestone, coal and gypsum. More controlled and predictable subsidence is characteristic of modern coal mining although anomalous subsidence does still occur, as do slope failures in the numerous cuttings, quarries, and opencast workings for road metal, limestone, fluorspar, calcite, barytes, coal and gypsum. Mining, and to a lesser extent quarrying, has had profound effects on the underground movement of water, particularly in the Peak District where the water table has been permanently lowered as a result of centuries of lead mining. A similar lowering of the water table, now reversed, resulted from over pumping of the Sherwood Sandstones. The management, including recharge and pollution control, of this aquifer is of major importance to Nottingham.
The wide range of foundation conditions reflects the range of rock types and problems vary from avoiding costly excavations for the M1 in hard Pre-Cambrian rocks to bridging the Trent over unconsolidated sands, gravels and peats. The extent of periglacial weathering is crucial in determining the foundation characteristics of Namurian, Westphalian, Mercia Mudstones and Jurassic strata and, as demonstrated by case histories, cannot be neglected in other formations.
Throughout the region there are conflicting interests arising from exploitation of resources in areas of considerable amenity value. Satisfactory solutions have been found for some of these problems, for example, with the nature reserves and Water Sports Centre developed from gravel workings, but others, such as the proposals for disposing of nuclear waste, have attracted much attention, but though temporarily postponed, remain unsolved.
