The paper describes ground subsidence and effect on historic buildings induced by the Earth Pressure Balanced (EPB) shield single tunnel construction of the first line of the Brescia Metrobus (Italy, 2005- 2009). The diameter of the shield is 9.15 m, the tunnel is 5.6 km long and excavation was carried out mainly in alluvial gravelly soil deposits. Among the buildings in Brescia the Palazzo della Loggia has been the venue of the city municipality since its construction between the 15th and 16Ith century. The progressive deterioration of the building massive piers and the forthcoming tunnel construction - located 25m from the building and 20m below ground level - required the consolidation of the soil beneath the foundations by means of low-pressure grouting and assessment of building settlements induced by the excavation. A number of finite element numerical simulations were carried out on a calibration-purpose model and preliminary results were compared with measured subsidence obtained from tunnel sections previously constructed. Predicted settlements and settlement distribution at the Loggia section were found in good agreement with movements measured during construction. Among the factors affecting subsidence prediction, particular attention was given to the ground loss during tunnel excavation and the presence of loads due to the building foundations. © 2010 Taylor & Francis Group, London.
Estimated settlements during the Brescia Metrobus tunnel excavation
Sanzeni A.
;Colleselli F.
2010-01-01
Abstract
The paper describes ground subsidence and effect on historic buildings induced by the Earth Pressure Balanced (EPB) shield single tunnel construction of the first line of the Brescia Metrobus (Italy, 2005- 2009). The diameter of the shield is 9.15 m, the tunnel is 5.6 km long and excavation was carried out mainly in alluvial gravelly soil deposits. Among the buildings in Brescia the Palazzo della Loggia has been the venue of the city municipality since its construction between the 15th and 16Ith century. The progressive deterioration of the building massive piers and the forthcoming tunnel construction - located 25m from the building and 20m below ground level - required the consolidation of the soil beneath the foundations by means of low-pressure grouting and assessment of building settlements induced by the excavation. A number of finite element numerical simulations were carried out on a calibration-purpose model and preliminary results were compared with measured subsidence obtained from tunnel sections previously constructed. Predicted settlements and settlement distribution at the Loggia section were found in good agreement with movements measured during construction. Among the factors affecting subsidence prediction, particular attention was given to the ground loss during tunnel excavation and the presence of loads due to the building foundations. © 2010 Taylor & Francis Group, London.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
