Reliability Analysis of Shotcrete Lining during Tunnel Construction

To a tunnel under construction, a prompt assessment of the stability of the lining through in situ measured data is of practical importance both for the observational designing of the tunnel and to guarantee the safety of construction. Among all the parameters measured during tunnel construction, displacement measurement is the most convenient and at the same time, the most credible and cost effective method to track the performance of tunnel lining. The aim of this paper is to develop a displacement-based method suitable for conducting reliability evaluation of the shotcrete lining in the progress of construction of a tunnel. First of all, a performance function at the cross section is put forward. Next, formulas are listed to calculate the internal forces in a lining segment. Then, the variability of the basic random variables is explained. Further, a process to compute the reliability index through measured displacements is presented. After that, two case studies are done. 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 reliability evaluation of shotcrete lining during tunnel construction and also is certainly of theoretical significance to a large extent.