Analysis of tunnel lining behaviour in soft soil during the construction stage, Second Heinenoord Tunnel

The paper addresses observations of the structural behaviour of the Tweede Heinenoordtunnel, a shield-driven tunnel in typical Dutch soft soils. Two rings were equipped with structural monitoring instrumentation. The measurements have shown that the assembly of the rings causes very significant initial forces and moments in the segments. Moreover, these initial forces and moments do not decrease significantly, as is often believed. Since conventional tunnel design models do not consider the effects of assembly on forces and moments, predicted maximum forces and moments in the lining appeared to be about half the measured values. Another important observation is that near the closing segment strong three dimensional effects occur as ring forces seem to migrate through small zones of the key segment.