The application of microgravity geophysics in a phased investigation of dissolution subsidence at Ripon, Yorkshire.
Patterson, D.; Davey, J.C.; Cooper, A.H.; Ferris, J.K.. 1995 The application of microgravity geophysics in a phased investigation of dissolution subsidence at Ripon, Yorkshire. Quarterly Journal of Engineering Geology, 28. 83-94. 10.1144/GSL.QJEGH.1995.028.P1.08Full text not available from this repository. (Request a copy)
Dissolution subsidence affords some of the most difficult ground conditions with which engineering geologists have to deal. Within the UK, areas underlain by gypsiferous Permo-Triassic strata, most notably around Ripon in Yorkshire, are prone to dissolution structures and resultant building failures are well documented. Conventional drilling of such unstable sites is often a ‘hit and miss’ affair and most geophysical techniques do not provide sufficient resolution to offer adequate confidence in the results. Proposals for the redevelopment of a site within the urban area at Ripon could not rely on such frequently inconclusive methods and it was necessary to implement a phased approach to site investigation. Following a desk study, high-resolution microgravity geophysics was carried out both inside and outside the existing building. This indicated a major negative anomaly of peak amplitude -74 µGal. Subsequent static core probing, rotary drilling and trial trenching confirmed the existence of a potentially unstable breccia pipe which could therefore be taken into account in the engineering design.
|Programmes:||BGS Programmes > Physical Hazards|
|NORA Subject Terms:||Earth Sciences|
|Date made live:||19 May 2011 15:55|
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