An Attempt to Predict the Failure Time of Abandoned Mine Pillars

• Published in: Rock mechanics and rock engineering Vol. 41; no. 3; pp. 377 - 401
• Main Authors: Castellanza, R., Gerolymatou, E., Nova, R.
• Format: Journal Article
• Language: English
• Published: Vienna Springer-Verlag 01.06.2008; Springer; Springer Nature B.V
• Subjects: Applied sciences; Buildings. Public works; Civil Engineering; Computation methods. Tables. Charts; Earth and Environmental Science; Earth Sciences; Exact sciences and technology; Experimental data; Failure analysis; Geochemistry; Geological engineering; Geophysics/Geodesy; Geotechnics; Gypsum; Mines; Miscellaneous; Structural analysis. Stresses; Structural engineering; Weathering; Italy; Europe; Keywords: Anhydrite, gypsum, mine, pillar, weathering; mine; Humidity transfer; Ageing; Theoretical study; Gypsum; weathering; Forecast model; Case study; Mining; Experimental result; pillar; Anhydrite; Old mine; Plane strain; Comparative study; Strength; Damaging
• ISSN: 0723-2632; 1434-453X
• DOI: 10.1007/s00603-007-0142-y

Summary Left in place pillars of abandoned mines are subject to weathering (e.g action of water, bacteria) that degrades their mechanical strength and eventually leads to collapse. A simple weathering model is proposed, that is governed by two parameters: the rate of progression of weathered front and the rate of degradation of the compressive strength with time. Both plane strain and axisymmetric analyses are performed and closed form solutions of the variation with time of the bearing capacity of the pillar are given. Experimental data of the tests conducted on gypsum and anhydrite specimens attacked by water are presented. It is shown that in order to fit the experimental data a third parameter must be introduced. New closed form solutions are given and the data are used for estimating the time to failure of abandoned gypsum mines in Northern Italy.