Using the section where the main line and ramps merge into the super-large span continuous variable cross-section of the Second Qingdao Jiaozhou Bay Subsea Tunnel, this paper proposed a dual guide tunnel advance-central column reverse excavation construction method under specific conditions to ensure the excavation construction stability of shallow-buried, large-span, continuously variable cross-section tunnels. The method's rationality and effectiveness were validated through finite element analysis and field monitoring data. The results showed that maintaining the original design's excavation partitions and using the proposed method could significantly enhance construction efficiency, with deformation and stress on the tunnel support structure within acceptable limits, ensuring structural safety and stability. Numerical simulation analysis showed that the reverse excavation of the central guide tunnel caused a rapid increase in the uplift of the invert, and stress concentration was likely to occur at the side walls of the tunnel, especially in the large-span section. During lateral excavation, the excavation of the lower bench significantly increased the load on the temporary support gantry, and stress concentration was prone to occur at the joints of the steel beams. During lateral expansion construction, the crown settlement and clearance convergence stabilized at approximately 9 mm, the initial support and surrounding rock contact pressure reached up to 70 kPa, and the maximum axial stress on the lining calculated empirically was about 0.354 MPa, with surrounding rock deformation and support stress meeting the standards. The dual guide tunnel advance-central column reverse excavation method had been successfully applied to the entrance section of the second Qingdao Jiaozhou Bay Subsea Tunnel.

In order to reveal the deformation characteristics of the adjacent structures induced by immersed tunnel trench excavation, the Ruyifang Radioactive System Project in Guangzhou was taken as the background to analyze the deformation law of the adjacent plant buildings and the reinforced revetment during the foundation excavation by 3D-dimensional simulation and field measurement. The research results showed that the soil on the slope surface of the foundation trench moved as a whole towards the direction of the foundation trench, with a maximum displacement of 23.65 mm along the direction of the foundation trench, occurring at the point of slope change in the middle of the slope; The excavation of the foundation trench induces the overall tilting of the factory building towards the riverbed, and the displacement of the factory building increased with the depth of the foundation trench excavation and eventually stabilized,the numerical results were consistent with the measured results,the maximum measured settlement of the factory building was 5.66 mm, and the maximum vertical displacement of the factory building in the direction of the embankment calculated numerically was 8.13 mm, the maximum ratio of the settlement difference between adjacent column foundations to the column spacing was 0.264‰, which met the requirements of the standard limit and ensured the safe operation of the factory building; The reinforced revetment deformed mainly in the vertical direction of the embankment with the variations of small at both ends and large in the middle and the maximum of 7.98 mm generating in the revetment top middle; The installation of steel sheet piles and foundation grouting at the top of the slope could effectively reduce the deformation of the factory structure, with a significant reduction in settlement. Compared with no measures taken, the simultaneous installation of steel sheet piles and grouting reinforcement could reduce the settlement of the factory structure by about 25%.

Traffic noise surface wave exploration holds significant promise for urban shallow subsurface investigations. However, current dispersion data is often limited by poor signal quality. To address these challenges, this research proposed a data quality control method specifically designed for traffic noise. The method enhanced signal-to-noise ratios through data screening and phase-weighted superposition, effectively improving the quality of the traffic noise surface waves. These improvements in signal-to-noise ratio and resolution contribute to more accurate dispersion imaging, as demonstrated by successful application to data from the Guangzhou Huanggang Power Tunnel. This research introduced a robust data quality control approach for traffic noise surface wave exploration, enabling broader use of traffic noise in surface wave investigations.

Taking a rapid transformation project in Shenzhen as an example, a numerical simulation method was used to establish a large-diameter shield tunnel of adjacent Mountain 3D model. The deformation and stress characteristics of shield tunnel with shallow overburden soil under biased pressure were analyzed. Based on the experience of anti-floating construction in similar projects, the box reinforcement scheme, the loading scheme, the uplift pile-pipe rooft-anti-floating plate scheme and the prestressed anchor cable-anti-floating plate scheme were proposed to control the deformation of shield tunnels. The results showed that during the evolution process of shield tunnel from biased overburden to shallow overburden, the vertical deformation of the tunnel was greater than the horizontal deformation, and the deformation was significantly asymmetric due to the influence of biased loads. In terms of force characteristics, the bending moment and axial force of the segments exhibited an irregular dumbbell shape as a whole. As the Biased pressure weakens, the shape of the internal force gradually shifts from dumbbell shaped to left-right symmetrical. Under various anti-floating measures, from the distribution range and scale of the plastic zone, the development range of the plastic zone was the smallest under loading scheme, followed by the prestressed anchor cable-anti-floating plate scheme. In terms of controlling tunnel deformation, the loading scheme was significantly better than the prestressed anchor cable-anti-floating plate scheme, the uplift pile-pipe rooft-anti-floating plate scheme, and the box reinforcement scheme had the worst effect on controlling deformation. The better the deformation control effect, the greater the stress on the shield tunnel under this scheme. It was recommended to adopt a prestressed anchor cable-anti-floating plate scheme for this project.

The multi-section excavation of the ultra-deep shaft service tunnel in Gaoligong Mountain was used as the engineering background, and the optimization of the shaft bottom yard, underground logistics organization, and vertical shaft transportation system was conducted based on the results of SUMO microscopic traffic numerical simulation software. The research results showed that rail transport at the shaft bottom was replaced with non-rail transport, which increased the shaft's mucking capacity to 1 000 m³/d, representing a 25% improvement. The layout of the shaft bottom yard, cross-sectional dimensions, and chamber configuration were optimized, which significantly enhanced transportation efficiency and reduced costs. Numerical simulation results of underground logistics organization showed that the average operating speed of muck transport vehicles was 74% of the maximum design speed. When the distance between the face and the shaft bottom yard was increased to 500 m and a cross-passage was added, no traffic conflict points were observed; however, when the vehicle spacing was too close, there was a risk of congestion. The vertical shaft transportation system was upgraded by modifying the hoisting systems in both the main and secondary shafts. The hoisting equipment was selected, and safety verification was performed, with corresponding safety control measures proposed.

In order to explore the distribution law of the initial ground stress field in the Ganqing Tunnel engineering area of Xicheng Railway and accurately predict the rockburst, the principle of multiple linear regression was adopted. Based on the measured stress data, landform, stratum & lithology, geologic structure and experimental research results, etc., the FLAC^3D numerical simulation analysis software was used to invert and analyze the initial stress field of the project area. The research analyzed the stress redistribution and local stress concentration after unloading during tunnel excavation, and predicted the specific location and strength of rock burst that may occur in the high stress section of the tunnel based on the modified "Gu-Tao rockburst criterion". The research results indicated that the Ganqing Tunnel is located in a high stress environment with complex geological structures, high stress concentration, and large burial depth. The Yanshanian diorite and Triassic slate rock masses were hard and intact, and there is a risk of rockburst; The maximum principal stress in the Ganqing Tunnel project area was 2.3-25.2 MPa, and the minimum principal stress was 1.0-15.8 MPa. The relationship between the triaxial principal stress was S_H>S_h>S_V when the burial depth was less than 300 m, and S_H>S_V>S_h when the burial depth was 300-700 m. The stress characteristics were mainly horizontal structural stress; The Ganqing Tunnel as a whole presented a weak to moderate rockburst state. The Ganqing Tunnel DK394+700—DK398+500 had the conditions for high rockburst activity, while DK384+500—DK394+700 and DK398+500—402+200 had the conditions for moderate rockburst activity.

To evaluate the impact resistance of super-large diameter shield tunnels under ground explosion loads, a three-dimensional refined finite element model was established using the fluid-solid coupling method. The influences on the shield tunnels under various explosive equivalents, burial depths and eccentric distances were compared. Tunnel performance indexes were formulated based on the maximum deformation and the quantity of yielded bolts. Subsequently, the tunnels were classified into four safety levels according to the post-explosion damage extent, and the influence zones of the super-large diameter shield tunnels under ground explosion loads were determined. This research could serve as a theoretical foundation for the site selection and reinforcement of shield tunnels traversing hazardous goods storage yard areas.

With in-depth implementation on ecological protection and high-quality development strategy in the Yellow River Basin, the development of the crossing tunnel in Shandong Province has become urgent, requiring solutions for the challenges of rail-and-road combined construction and security guarantees. Through engineering analogy, modeling, and numerical testing methods, and considering the surrounding environmental protection and hydrogeological characteristics, key design techniques and risk control measures for the Jinan Jiluo Road Yellow River North Extension Tunnel had been summarized and analyzed. The results showed that the application of collaborative evacuation technology and a comprehensive ventilation system enabled a more efficient shield tunnel design. And the adoption of a “segment+non-closed lining” calculation model, segment inter-ring shear structure, and integrated waterproofing methods enhanced the overall stiffness and bearing capacity of the shield tunnel. And the available closing time of the anti-flooding door was calculated, which provided a theoretical basis for the design of the tunnel' santi-flooding system. Additionally, the use of prefabricated internal structures helped control the tunnel's section diameter and accelerated construction speed. On-site monitoring confirmed that construction risks were manageable and the overall design was reasonable and feasible.

Based on a groundwater sealing cavern project, based on the on-site single-hole water injection-fall test data and the water curtain connectivity test data, the permeability of the rock mass and the connectivity between the water curtain holes were obtained, and the method for judging the tightness of the cavern based on the vertical water curtain test was proposed, and the effectiveness of the vertical water curtain hole and the sealing of the cavern were determined, then the effectiveness analysis method of the vertical water curtain system was proposed, which provided a basis for the subsequent optimization design of the vertical water curtain system, so that the design of the water curtain system was reasonable and the water sealing of the cavern was guaranteed.

In order to deeply understand the deformation and rupture process of coal samples, the early warning discrimination model of coal rock damage monitoring based on acoustic emission precursor information was established to provide an important basis for mine safety production. By constructing a lightweight three-dimensional convolutional coal rock damage identification model integrating acoustic emission temporal and spatial features, the prediction effect of the identification model for different stages of coal rock damage was studied, and the model's generalization ability was verified. The prediction accuracy of the coal rock damage recognition model was 99.39% in the validation samples of identifying the damage hazard stages of coal samples, and the recall rate of the high-risk samples was also more than 99.20%, which indicated that 3D convolution could effectively captured the coupled spatio-temporal information of the acoustic emission waveforms of coal sample damage. Moreover, the ConDenseNet with SE model could be optimized by knowledge distillation to further reduce the degree of model overfitting and obtain a coal damage recognition model with both performance and accuracy, which verified the superiority of the optimized ConDenseNet with SE model in identifying coal damage and damage warning.