Chengping Zhang

Shield tunnels in operation are often affected by complex geological conditions, environmental factors, and structural aging, leading to cumulative damage in the segments and, consequently, increased deformation that compromises structural safety. To investigate the deformation behavior of tunnel linings under random damage conditions, this study integrates finite element numerical simulation with deep learning techniques to analyze and predict the deformation of shield tunnel segments. First, a refined three-dimensional finite element model was established, and a random damage modeling method was developed to simulate the deformation evolution of tunnel segments under different damage ratios. Additionally, a statistical analysis was conducted to assess the uncertainty in deformation caused by random damage. Furthermore, this study introduces a convolutional neural network (CNN) surrogate model to enable the rapid prediction of shield tunnel deformation under random damage conditions. The results indicate that as the damage ratio increases, both the mean deformation and its variability progressively rise, leading to increased deformation instability, demonstrating the cumulative effect of damage on segment deformation. Moreover, the 1D-CNN surrogate model was trained using finite element computation results, and predictions on the test dataset showed excellent agreement with FEM calculations. The surrogate model achieved a correlation coefficient (R²) exceeding 0.95 and an RMSE below 0.016 mm, confirming its ability to accurately predict the deformation of tunnel segments across different damage conditions. To the best of our knowledge, the finite-element–deep-learning hybrid approach proposed in this study provides a valuable theoretical foundation for predicting the deformation of in-service shield tunnels and assessing structural safety, offering scientific guidance for tunnel safety evaluation and damage repair strategies.

When the tunnel passed through a water-rich stratum, the Water Rock Interaction could cause damage to the rock, which had adverse effects on the tunnel engineering. When the water environment changed, a great risk existed in the tunnel during construction. In this paper, Water Rock Interaction was classified as water rock physical interaction, water rock chemical interaction, and water rock mechanical interaction, which is significantly affected by temperature and humidity. Then, the macroscopic and microscopic physical properties of rock under the dry-wet cycle and freeze-thaw cycle were summarized. The influence on tunnel stability was analyzed by the classification of water damage in the tunnel. Finally, the waterproof and drainage systems of tunnel engineering were summarized, and future research directions were put forward.

Based on the theoretical analysis of the integrated development of power grid enterprises serving the Yangtze River Delta, a set of systematic scientific and perfect evaluation index system of service “Integration of Yangtze River Delta” development ability was established. AHP is used to determine the weight of each index in the evaluation system and screen out the key index. The analysis results show that Anhui company is in a leading position in green development, there is not much gap with Shanghai, Jiangsu and Zhejiang companies in quality service and integrated coordination mechanism, and there is a big gap with Shanghai, Jiangsu and Zhejiang companies in infrastructure construction and industrial development.

The improvement of the contact state between the surrounding rock and tunnel lining, such as the effect of back-fill grouting behind lining, was important for maintaining the stability of the lining structure. To explore the influence of loose contact states behind lining on the safety of tunnel lining, a case of field investigation in a railway tunnel with a symmetrical lining structure was presented in this paper. A model test was conducted to prove the accuracy of the numerical simulation in the condition of dense contact state between the lining and surrounding rocks. Based on this, the three-dimensional (3-D) impact of loose contact states on the mechanic behavior of the lining structure under different compactness and different loose contact areas behind lining was investigated and summarized. Furthermore, the influence of the percentage of the insufficient strength behind lining was explored. Finally, the grade of the influence of the loose contact state on the safety of the lining structure was classified. The results revealed that: (1) in order to maintain the stability of lining structure, the compactness of the back-fill grouting behind lining was recommended to be above 80%, and the range of the loose contact area should be no more than 60 degree; (2) the strength of the back-fill grouting behind lining should be above 50% strength of the surrounding rock, the loose contact state behind lining should be improved in time to avoid expansion of the loose contact area; and (3) the classification of the influence grade on the safety of the lining structure provides a basic reference for controlling the quality of the back-fill grouting. This research gives a new point of view for the evaluation of the contact state between lining and surrounding rock.