Assessment on the safety of shotcrete lining during tunnel construction

To a tunnel under construction, a prompt assessment to the safety of the lining through in-situ measured data is of practical importance both for the observational designing of the tunnel and for the construction safety. Among all the parameters measured during tunnel construction, displacement is widely used and thus accepted as a very essential quantity, due to its advantages in convenience, low cost and high credibility. The aim of this paper is to develop a displacement-based method suitable for conducting safety evaluation of the shotcrete lining in the progress of construction of a tunnel. First of all, the performance function at a cross-section is put forward. Next, formulae are listed to calculate the internal forces for a lining segment. Then, the variability of the basic random variables is expatiated. Later on, iterated is the computation process of the reliability index through measured displacements. After that, case studies are conducted. Finally, the nature of the proposed method is observed and some remarks are made on further developments. The proposed method can meet the need of safety evaluation of shotcrete lining during tunnel construction and is also certainly of theoretical and practical significance to some extent.