Metro Sofia, Line 2
Optimisation of the segment profile through slice pressure tests
As part of the expansion of the metro system in the Bulgarian capital, 3.7 km of tunnel were excavated using EPB shields. Thanks in part to the good segment design, a peak performance of 220 m was achieved in one week. The maximum permissible jacking force was determined beforehand by means of disk pressure tests, taking into account an off-center offset.