Functional model for ultimate load-bearing capacity of segmental lining

To investigate the composition elements of the ultimate load-bearing capacity of segmental tunnel lining (lining system) and explore the intricate relationships between lining capacity and contributing factors, as well as the relationships between system failure and its inducement, this study focuses on deriving analytical expressions for the ultimate load-bearing capacity of the lining system. This research is based on the analytical solution for segment joint with inclined bolts, along with incorporating the theory of Failure Mode and Effects Analysis (FMEA). Firstly, the analytical expressions for the ultimate load-bearing capacity of individual system components (such as segment joints and segments) are introduced. Secondly, the functional expression of failure modes of the lining system is suggested, and a functional model for the capacity of segmental lining system is presented. Finally, some applications of the presented system functional model are discussed. It demonstrates that: (1) Based on this model, the system capacity is a function of three types of variables: joint capacity, segment capacity, and failure mode function. (2) This function model can be used to represent the interrelationships between the factors affecting the ultimate load-bearing capacity and to classify the contributing factors into five levels; (3) According to the load-bearing capacity model and the hierarchical diagram of the influencing factors, it can be revealed that the function mechanism of contributing factors of system capacity, as well as the interactions between the influencing factors.