Solution for the conclusion of the Mackenzie access in Sao Paulo Line 4 Subway
The Mackenzie access of Higienópolis Station, of the Sao Paulo Line 4 subway consists of two siccative shafts, one of them was built several years ago and the construction of the second one began in 2012. When 31 m of the second shaft were excavated, it was a soil piping phenomena in the bottom of the shaft. To complete the construction of the Mackenzie Shaft the monitoring data was analyzed by a back analysis to set up the properties of the grown which matched well with the monitoring data. After this, the feasibility of completing the excavation with the protection of jet-grouting piles was verified. The calculations carried out showed that the safety factor was 1.4. In late 2013 it was proceeded to remove the ground stacked in the bottom of the shaft; prior activity to complete the excavation, which was planned in seven sectors. During the excavation of sectors 2, 5 and 7 some problems appeared which were resolved by a punctual drainage. The excavation ended June 24, 2013.