The Portoro “marble” is a fine variety of black limestone from the La Spezia area, in Liguria (North-western Italy), which consists of a Liassic limestone with limonite and calcite veins. The Portoro typically crops out close to the Portovenere village and Poets’ Gulf area, which is very known and sensitive in terms of scenery and tourist appeal. Even if few stone quarries are still working, it is evident how quarrying must be done with special care. So underground excavation is more and more developing, in order to control waste production, environmental impact and slope instability: big blocks are mined in large underground chambers whose roofs are supported by pillars. In this study a numerical modeling, based on a distinct element method was used, in order to compare stresses and displacements with the in situ measurements and to reach an optimum quarrying design. This research mainly aimed at improving the working conditions, as regards different topics: work safety in underground environment; prevention of fracturing of intact rock, induced by excessive stress concentration; improvement of the extraction process, to quarry intact, bigger stone blocks and produce less waste material; providing the underground chambers with long-term stability conditions, for possible future use.
Pillar sizing and stability analysis by numerical modeling for underground stone quarrying
SCIARRA, Nicola;CALISTA, Monia;
2012-01-01
Abstract
The Portoro “marble” is a fine variety of black limestone from the La Spezia area, in Liguria (North-western Italy), which consists of a Liassic limestone with limonite and calcite veins. The Portoro typically crops out close to the Portovenere village and Poets’ Gulf area, which is very known and sensitive in terms of scenery and tourist appeal. Even if few stone quarries are still working, it is evident how quarrying must be done with special care. So underground excavation is more and more developing, in order to control waste production, environmental impact and slope instability: big blocks are mined in large underground chambers whose roofs are supported by pillars. In this study a numerical modeling, based on a distinct element method was used, in order to compare stresses and displacements with the in situ measurements and to reach an optimum quarrying design. This research mainly aimed at improving the working conditions, as regards different topics: work safety in underground environment; prevention of fracturing of intact rock, induced by excessive stress concentration; improvement of the extraction process, to quarry intact, bigger stone blocks and produce less waste material; providing the underground chambers with long-term stability conditions, for possible future use.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
