Analysis of the failure of the foundation of a tunnel. Design and justification of a constructive solution

Abstract

This paper presents the results of a forensic analysis of a tunnel above which an embankment was
built that served as a roadbed. The joint tunnel–embankment structure is located on the outskirts of the town of Piedrafita in northwestern Spain. The tunnel channels the course of the River Vilela in its crossing of the aforementioned road.This article presents a detailed report of the problem, including the damage caused to the structure of the tunnel and the embankment, and it presents the measurements taken, the determination of the origin
of the problem and finally a constructive solution is proposed. For this determination, a numerical simulation of
the joint tunnel–embankment–ground structure was conducted on the basis of the data obtained from tests carried out both in situ and in the laboratory. The study was complemented by an analysis performed using classical methods that confirmed that the movements detected in the overall structure were caused by the collapse of
the foundations. The uniqueness of the study presented in this paper lies in the failure analysis and in the reinforcement of the tunnel structure proposed that it is consistent with the reasons for such failure..