Measurement and numerical modelling of the process of tunnelling

In order to obtain a precise and reliable measurement database for the vali dation and qualification of simulation tools describing the deformations in duced by tunnelling operations, two sites on the Lyon Metro D line extensio n have been intensively monitored. This paper presents the results of measu rements from two experimental transverse tunnel sections of this line, A co mparison with data from previous projects shows that the instability of the tunnel face and the annular void created by the passage of the shield cons titute the principal sources of short-term settlement. Based on these measu rements, a new procedure of numerical simulation in the plane strain condit ions is proposed, taking into account various stages of construction. The c omparison of the observed and simulated movements shows that the behaviour of soft ground is better simulated by displacement control than by stress c ontrol of the periphery of the excavation.