Ironbridge Gorge

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Ironbridge Gorge

• Charlotte Gibson
• Andrew Illingworth
• Jon Elliott

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Content

• Geology of the area.
• Problems.
• Engineering Solutions.

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History

• Industrial revolution- Iron and ceramics
• Coal
• Iron ore (mining)
• Coke limestone (blast furnaces)
• Sand (moulding cast iron)
• Clay (bricks, tiles)
• Today-
• World heritage site
• Tourism

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Geology

• Geologically young
• Still developing
• Erosion slippage will continue until balance
  reached
• Rocks originally deposited as horizontal strata
  before being tilted, folded and faulted to form
  present structure.
• Solid geology made up of Silurian Carboniferous
  age rocks (400 and 280 million years old)

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Age Unit Description Appox Thickness
Carboniferous Upper Coal Measures Mudstones, Sandstones, Thin coal seams 120m
Carboniferous Middle Coal Measures Mudstones, Sandstones, Thin coal seams 15m
Carboniferous Lower Coal Measures Mudstones, Sandstones, Thin coal seams 15m
Carboniferous Limestone Series Limestone 55m
Carboniferous Basalt
Silurian Wenlock Limestone Limestone with interbedded siltstones 15-17m
Silurian Thickwood beds Shales with limestone nodules 15-25m
Silurian Wenlock shales Mudstones with thin beds of limestone and bentonitic clay 100m
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Geological Map
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Problem of Landsliding

• Gorge slopes covered by a complex of vaneer of
  colluvium.
• Rates of movement of colluvium vary over the
  gorge.
• Active-landslip in more underdeveloped areas.
• Evidence of ground movement in developed areas.
• Still susceptible to more landslides.

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Problems caused by mining

• Heavily mined during the industrial revolution.
• Waste material causing surcharge.
• Abandoned workings deteriorating.
• Mine voids creating drainage paths.
• Modern development causing local steepening and
  extra surcharge.

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General Solutions

• Retaining walls
• Gabion walls
• Effective drainage
• Services above ground
• Management plans

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Complex Solutions

• Slatted road surface
• Excavation of landslide
• Inverted arch on bridge
• Reinforced concrete tubes