2019 Volume 75 Issue 1 Pages 40-55
Heaving in some mountain tunnels after completion occurs in roadbeds that were built without an invert because the ground was relatively stable during construction. The stress-release by excavation, along with subsequent swelling of groundwater, cause the roadbed to lose strength, allowing upheaval of the road surface.
In this study, we analyzed geological degradation characteristics and the state of past tunnels in cases where inverts were installed. And, we used measurement data to compare axial forces of inverts with axial forces of early-closure primary inverts in other tunnels at the construction stage. Based on these, we discuss the necessary performance. As a result, we used numerical analysis to compare support effectiveness of the invert shape and considered a rational structure.
