Xuzhou Earth Subsidence

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Xuzhou Earth Subsidence

• Xing Zhang
• Yifan Zhang
• Fan Yang

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Where is Xuzhou
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Local Geology
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Local Geology

• A Large-scale Coal Mine
• locates at this area.

• The problem of subsidence
• here is quite serious.

• Use TRANSIENT ELECTRO-
• MAGNETIC METHOD to analysis
• local geology.

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Analysis of Subsidence Area

• The deep blue area shows
• low-resistivity zone which
• means aquifer.

• The rise of the level of ground
• water in recent years is due to
• excavated old tunnel.

• The collapsed post by this method
• has been confirmed by field drilling

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Earth Subsidence Formation

• Coal hollow
• Ground water penetration
• Effective pressure losses
• Gravity

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Problems Encountered

• Changes in elevation
• Damage to structures such as roads, railroads,
  bridges and pipe network
• Danger to life safety
• Damage to private and public properties
• Reduce the use value of the land

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• Earth subsidence in a construction site

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• Earth subsidence on a road

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• Earth subsidence on a bridge

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Major Solution-Grouting

• Use stone columns as foundation.

• Impregnate grout to fill possible
• hole under foundation and prevent
• future subsidence .

• Some high-risk road decks were
• made of reinforced concrete to
• improve strength.

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Solution for Road -Cement Mixing Pile

• Cement mixing piles used to
• strengthen road sub-base.

• Designed to support road for
• 24 hours after subsidence.

• This allows remedial action(mostly
• grouting) to be taken.

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Solution for Building

• Piles used to strengthen sub-base.

• Piles control settlement and prevent
• future subsidence .

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Thanks very much!
Any questions?