JMZX-5040am dual-mode pressure cells were, respectively, installed on the
tunnel vault, tunnel arch (right), and right side wall of the K14 + 400 section to test the pressure change between the surrounding rock and the initial support.
Therefore, in this study, considering real excavation and three dimensional modeling effects, the results of two and three dimensional tunnel excavation models such as
tunnel vault and invert displacement (i.e., the measure of convergence at the tunnel section) and stress state around the tunnel opening were compared by means of a finite-element method based on 2D and 3D tunnel models.
In this project, the monitoring items include the settlement, inclination and cracking of the surrounding buildings, the vertical displacement of the adjacent underground colligation pipelines, the settlement of the ground surface, the underground water level, the sink deformation of the
tunnel vault, the tunnel bottom heave, and the tunnel clearance convergence.
(2) When the water head difference over the excavation face reaches the limit value of 18 m, longitudinal joint opening at
tunnel vault reaches the maximum value of 4 mm.
In fact, the position of the maximum bending moment at 90[degrees] of the lining section was transferred to the range of 200[degrees] to 240[degrees] (the apex of the tunnel is at right side of lining, thus, the
tunnel vault is taken to be 90[degrees]).