The nature, formation and engineering significance of sinkholes related to dissolution of chalk in SE Hampshire, England

McDowell, P. W.; Coulton, J.; Edmonds, C. N.; Poulsom, A.J.

doi:10.1144/1470-9236/07-209

Cited by 12 publications

(4 citation statements)

References 21 publications

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“…Thorez et al 1971), but this is considered to be a different process that tends to be associated with doline or pipe formation at the feather edge of the cover deposits (e.g. McDowall et al 2008).…”

Section: Dissolutionmentioning

confidence: 99%

Anomalous buried hollows in London: development of a hazard susceptibility map

Banks

Bricker

Royse

et al. 2015

QJEGH

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Engineering works carried out in central London over many decades have revealed a number of buried hollows that exhibit curious characteristics. Some extend deep into the bedrock geology and are in-filled with disturbed superficial deposits and reworked bedrock. Others are contained within the superficial deposits. They can be up to 500 m wide and more than 60 m in depth. As the infill material often has different behavioural characteristics from the surrounding deposits failure to identify them during an initial site investigation can prove costly. This paper considers their common characteristics and describes the method used to develop a buried hollow hazard susceptibility map. This map provides planners with a broader awareness of the potential location of difficult ground conditions associated with them, thereby reducing the potential for unforeseen ground conditions through effective site investigation design. The paper continues with a discussion of some of the likely processes associated with their formation, which are attributed to cryogenic processes, and concludes with potential future research directions.

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Section: Dissolutionmentioning

confidence: 99%

Anomalous buried hollows in London: development of a hazard susceptibility map

Banks

Bricker

Royse

et al. 2015

QJEGH

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“…The position of the North Mymms recharge mound as favourable for providing a driving head, and the relative flatness of the water table east of Hatfield mean that other as yet unidentified features, such as structural axes and buried valleys in the Paleocene subsurface (e.g. McDowell et al 2008), might provide significant transport routes.…”

Section: Scale and Extent Of Solution-enhanced Conduitsmentioning

confidence: 99%

Modelling the influence of solution-enhanced conduits on catchment-scale contaminant transport in the Hertfordshire Chalk aquifer

Cook

Fitzpatrick

Burgess

et al. 2012

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Catchment-scale (>40 km2) contamination of the Chalk aquifer of Hertfordshire by bromate, emanating from a disused industrial site north of St Albans, represents the largest occurrence of point-source groundwater contamination in the UK. The influences of ‘double porosity’ diffusive exchange and rapid transport along solution-enhanced conduits complicate predictive modelling of contaminant transport to threatened public supply wells. Tracer testing indicates that solution-enhanced flow routes exist beyond the surface distribution of dissolution features in Hertfordshire, more extensively than previously thought. A quantitative conceptual understanding of this flow system has been incorporated into a spatially distributed equivalent porous media representation in MODFLOW and MT3D-MS. The calibrated model reproduces essential features of the aquifer system, including heads and flows, seasonal responses, and the timing and spatial distribution of observed tracer breakthroughs in the solution-enhanced aquifer, but does not fully capture the magnitude and form of tracer and bromate advance. Due to the influence of local solution enhancement and matrix effects, detailed breakthroughs at receptors cannot be resolved at the coarse grid scale. However, the model is able to simulate general trends.

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“…This is particularly important as the Chalk often underlies major transport corridors and several large urban areas. Chalk dissolution also generates subsidence hazards and difficult engineering conditions (Edmonds, 1983;Edmonds, 2001a;Edmonds, 2001b;Edmonds, 2008;Farrant, 2001;McDowell, 2005;McDowell et al, 2008) Problems include metastable cavities, irregular rockhead associated with the development of clay filled pipes and fissures, localised subsidence, increased compressibility and diminished rock mass quality. In the north of England (Yorkshire through to Lincolnshire) the Chalk is relatively hard and part of the area has been stripped by several glaciations removing many of the surface karstic features.…”

Section: Cretaceous Chalkmentioning

confidence: 99%

“…In Norwich subsidence sinkholes have caused problems, sometimes compounded by mining induced subsidence (Howard Humphreys and Partners Ltd, 1993). In Kent and around the Thames estuary, the Chalk is overlain by the permeable Thanet Sand, resulting in subsidence affecting the covering deposits (Ellison, 2004;McDowell et al, 2008).…”

Section: Cretaceous Chalkmentioning

confidence: 99%

The use of karst geomorphology for planning, hazard avoidance and development in Great Britain

2011

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Within Great Britain five main types of karstic rocks -dolomite, limestone, chalk, gypsum and salt -are present. Each presents a different type and severity of karstic geohazard which are related to the rock solubility and geological setting. Typical karstic features associated with these rocks have been databased by the British Geological Survey (BGS) with records of sinkholes, cave entrances, stream sinks, resurgences and building damage; data for more than half of the country has been gathered. BGS has manipulated digital map data, for bedrock and superficial deposits, with digital elevation slope models, superficial deposit thickness models, the karst data and expertly interpreted areas, to generate a derived dataset assessing the likelihood of subsidence due to karst collapse. This dataset is informed and verified by the karst database and marketed as part of the BGS GeoSure suite. It is currently used by environmental regulators, the insurance and construction industries, and the BGS semi-automated enquiry system. The database and derived datasets can be further combined and manipulated using GIS to provide other datasets that deal with specific problems. Sustainable drainage systems, some of which use soak-aways into the ground, are being encouraged in Great Britain, but in karst areas they can cause ground stability problems. Similarly, open loop ground source heat or cooling pump systems may induce subsidence if installed in certain types of karstic environments such as in chalk with overlying sand deposits. Groundwater abstraction also has the potential to trigger subsidence in karst areas. GIS manipulation of the karst information is allowing Great Britain to be zoned into areas suitable, or unsuitable, for such uses; it has the potential to become part of a suite of planning management tools for local and National Government to assess the long term sustainable use of the ground.

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The nature, formation and engineering significance of sinkholes related to dissolution of chalk in SE Hampshire, England

Cited by 12 publications

References 21 publications

Anomalous buried hollows in London: development of a hazard susceptibility map

Anomalous buried hollows in London: development of a hazard susceptibility map

Modelling the influence of solution-enhanced conduits on catchment-scale contaminant transport in the Hertfordshire Chalk aquifer

The use of karst geomorphology for planning, hazard avoidance and development in Great Britain

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