Predicting mine collapse


Northern France is riddled with limestone mines that occasionally collapse creating a ring-shaped crater on the surface that can cause serious damage to nearby buildings.

Is there any way to predict these failures and thereby attempt to prevent them?

If there is, Siavash Ghabezloo and Ahmad Pouya from the Laboratoire Centrale des Ponts et Chaussées in Paris, seem determined to find it and publish their initial efforts today.

Their approach is to assume that mine failure is the result of weathering in  limestone rock, in other words the reaction of carbon dioxide, water with calcium carbonate. This dissolves the rock, severely weakening it until it collapses.

Ghabezloo and Pouya introduce a set of equations that govern the different hydro/chemo/ mechanical aspects of this weathering phenomenon. They then attempt to model the process numerically.

That’s all very well but does it get us any closer to predicting collapse? Unfortunately not. Validating their model will be difficult to say the least and applying it to a real mine almost impossible.

And even if it could predict how fast such weathering might occur, how would it predict where it was happening?

Nice try but no cigar.

Ref: Numerical Modelling of the Effect of Weathering on the Progressive Failure of Underground Limestone Mines

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