Correlation between the kinematics of a Tunnel Boring Machine and the observed soil displacements

Constructing tunnels in soft soil with the use of Tunnel Boring Machines (TBMs) may induce settlements. A considerable amount of the total soil displacements is correlated with the passage of the TBM-shield. Even so, the TBM-induced soil displacements are so far only coarsely correlated to the total settlements. This paper relates the shield geometry and its advance through the soil with the observed soil displacements. The snake-like motion of the shield induces unevenly distributed soil displacements at the shield-soil interface, which spread through the soil with a similar pattern. The results of an earlier numerical investigation on the TBM kinematics and the observed soil response are compared here in order to quantify their correlation. The analysis has been based on the monitoring data from the construction of a twin-tube bored road tunnel in The Hague, The Netherlands. Results confirm that the geometry and the advance of the TBM-shield through the soil influence the amount and distribution of the induced soil displacements. The analysis also highlights the essential role of the tail-void grouting not only in filling-in the tail-void, but also in compensating the kinematical effects of shield advance.