# A Novel Visual System for Conducting Safety Evaluations of Operational Tunnel Linings
###### Abstract  
Based on the lining structure of an operational tunnel, the AHP and Fuzzy mathematical models were used to determine the weight of the evaluation index and solve the membership matrix. The weighted-average Fuzzy comprehensive function was used to combine the two, and the Fuzzy-AHP evaluation model was built and programmed. According to the self-developed Fuzzy-AHP evaluation-programmed model, a visualized structure safety evaluation system for operational tunnels was developed by using MATLAB. The system's functional design, program development, and computational visualized interface were implemented, and key codes were provided. The system can be divided into four modules: data management, fuzzy computation, predictive analysis and key disease indexes to focus on. In addition, the system can easily edit and modify the evaluation function, which includes not only the Fuzzy evaluation but also other types of evaluation functions applicable to other practical engineering projects, improving the applicability of the system. After that, the system was applied to the structure safety evaluation of a mountain tunnel, which provided the evaluation results and key indexes to focus on in the tunnel. Finally, the rationality of the system design was verified by constructing the corresponding BP-RBF combined neural network. This study provides a reference for the establishment of an intelligent structure safety warning system for operational tunnels. lining structure; Fuzzy-AHP; MATLAB; safety evaluation of operational tunnels; BP-RBF combined neural network +
Footnote †: journal: Applied Sciences  
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cave depth. These diseases can bring many serious problems: lining cracking can cause a reduction in structural bearing capacity; tunnel headroom becomes smaller and intrudes into the building limit, which affects driving safety; leakage of water leads to corrosion of tunnel facilities and freezing damage; and when the caves in the lining are serious, the surrounding rock will become unstable and collapse. However, there is insufficient research on the structure safety of operational tunnels, making it difficult to conduct standardized and quantitative safety evaluations [7; 8]. Previous structure safety evaluations of tunnels mainly focused on the construction period, the purpose of which was to obtain the structure safety status in a timely manner and guide further construction [9; 10]. With the increasing number of tunnels already constructed, structure safety evaluations of operational tunnels have received continuous attention, especially with respect to the development of quantitative evaluation methods instead of traditional qualitative methods. Some theoretical models have been applied in safety evaluations of operational tunnels. However, these methods have only demonstrated theoretical feasibility and have not been effectively applied in practical engineering projects [11; 12; 13; 14; 15; 16]. One important reason is that the above models were too complex and specialized, resulting in insufficient applications. Therefore, there is an urgent need to develop a visualized safety evaluation system that is easy to operate for operational tunnels. The development of a visualized system is based on an algorithmic model. A sound evaluation system must possess a well-developed algorithmic model, which serves as the core of the system. Research indicates that the Fuzzy-AHP model is an ideal model for evaluating structure safety due to its ability to effectively solve problems that are difficult to quantify, which makes the results more objective [17; 18; 19]. However, there have been few reports on the development of a programmable and visualized structure safety evaluation model for operational tunnel by combining Fuzzy and AHP.