A new generation method of tunnel progressive defect status random field (TPDSRF) for subway tunnel structure

Abstract

Subway tunnels are exposed to the risk of multiple hazard attacks such as earthquakes, fires, and explosions during operation, which can cause significant damage to their structure. The presence of progressive defects can exacerbate this damage, but existing hazard design methods do not consider their effects, leading to inaccurate damage assessments. To fill this gap, this study proposes a method to characterize the state of progressive defects in the design stage that may appear in a shield tunnel during a tunnel's operational phase. Firstly, based on the progressive defect situation of the operating tunnels, it was determined that the s status of the defects can be described by stochastic and correlation characteristics. To describe these characteristics, the Tunnel Progressive Defect Status Random Field (TPDSRF) is defined. The study then derives the parameters and range of five progressive defects that describe TPDSRF, using a combination of engineering measurement data and literature research. Finally, the study describes the entire generation process in detail and simulates a TPDSRF for a 1000 rings subway tunnel. Results show consistency with preset values and tunnel progressive defect patterns, demonstrating the feasibility of the proposed method. The results of the study can provide a improving initial state of the structure for hazard analysis, which is important and essential for the analysis of structural hazard damage under the consideration of progressive defects.