The research background was the construction of large-scale lined cavern gas storage for a deep anhydrite ore body in Anhui province, the thermal-mechanical coupling analysis method based on ABAQUS finite element software was used, established numerical model under the gravity stress field, the deep cavity multi cycle under different cavern spacing was apart from the temperature, the gas extraction in the process of filling the key stratum structure deformation, stress distribution and the change process.The distribution law of surrounding rock plastic zone and the change process of surface deformation under different cavern spacing were investigated.The results showed that the temperature of the main structural layers was not affected by increasing the cavern spacing.When the cavern spacing was less than 2 times the hole diameter, changing the cavern spacing had obvious effects on the stress and deformation of key structural layers, surface displacement, tensile stress distribution and size of concrete lining, and plastic zone distribution of surrounding rock, and the interaction between gas storage was more significant.When the cavern spacing increased to 2 times the cavern diameter, the interaction between gas storage was no longer obvious, and the increase of cavern spacing had no obvious effect on the stability of gas storage.

This research summarized the basic concepts of compressed air energy storage(CAES)underground caverns from an engineering perspective, analyzed the basic structure of caverns and the main load characteristics of caverns during operation. On this basis, the basic design concept of flexible sealing structure was put forward, and the reliability design method was suggested to be adopted in the construction of underground caverns, which also provided the guidance and design principles, operation, and maintenance of CAES underground caverns.

Long tunnel in homogeneous stratum was studied, which was simplified to a beam on elastic foundation. Soil-structure interaction was simulated by normal and tangential spring. Analytical solution of longitudinal seismic response was derived by solving governing differential equations. Through the analysis of the analytical solution of the internal force response, the calculation method of the maximum internal force response required for the longitudinal seismic design was put forward, which could be used to calculate the most unfavorable longitudinal response of long tunnel. On the basis of numerical calculation, the correctness of the analytical solution was verified. In addition, the analytical solution could intuitively give the correlations among the key parameters. Through parametric analysis, influence laws of incident angle, incident wavelength and relative stiffness ratio on longitudinal seismic response of tunnels were obtained. Analysis showed that as the wavelength of incident wave increased, the bending moment response first increased and then decreased, and the shear force and axial force response decreased. If the incident angle increased from 0° to 90°, the shear response decreased, while the bending moment and axial force first increased and then decreased. As the relative stiffness ratio increased, internal force response was reduced, but the displacement response of the structure and the deformation of tunnel structure would appear larger, which should be considered in the structural design. On this basis, a reasonable design and calculation method of longitudinal seismic response analysis of long tunnels was put forward, which could provide guidance for longitudinal seismic design of long tunnels.

This study aimed to enhance shield muck by incorporating foam agent and active magnesium oxide. The fluidity, bleeding rate and compressive strength of the improved soil under different foam agent and active magnesium oxide content were obtained by fluidity, bleeding rate and compressive strength test. It was showed that the improved flowable backfill soil exhibited excellent fluidity and solidified strength. By adjusting the content of foam agent and active magnesium oxide, the flowable backfill soil with fluidity ranging from 180 mm to 320 mm, bleeding rate below 5%, and 28-day compressive strength between 0.6 MPa and 1.2 MPa could be obtained.

The development history, cavern composition and role of underground compressed gas energy storage technology were systematically introduced, and the development status of underground lined cavern technology was discussed. This paper systematically analyzed the research progress of three key problems of underground lined caverns, namely ultimate storage pressure, thermodynamic effects in the process of gas injection and production, and sealing performance of cavern lining, summarized the existing research results, pointed out its limitations, and put forward suggestions for the future research direction of underground lined caverns.

In order to deal with the problem from the large difference in the stress release rate of shield tunnels in different strata and the difficulty to accurately define the stress release rate in numerical calculations, it was studied about the correlation between the loss of the stratum and the stress release rate of the shield tunneling process. A method was proposed, which defined the stress release rate by taking the over-excavation of the cutterhead as the control index, and the application time of the shield shell, grouting, segment supporting and other processes was corresponding to the specific stress release rate. The geometric and physical mechanical parameters of the shield-soil clearance and the overlying stratum in the engineering background were combined, a high-simulation calculation method for the whole process of tunneling with shield tunneling machine was established to realize fine simulation of disturbance deformation. The comparison between the calculation results and the monitoring results proved the correctness of the research method. The simplified calculation method based on the comprehensive control parameters of the stress release rate accurately simulated the stratum deformation of the entire shield construction process in soil texture and improved the calculation accuracy, which could quickly complete the accurate prediction of the shield construction process.

In many cases of shield tunnel collapse accidents occurred both domestically and internationally, the development process of the collapse showed the characteristics of progressive collapse, leading to serious economic losses and casualties. However, the research is still in its primary stage. The lack of understanding of the triggering conditions, development process, and effective prevention measures of the progressive collapse of shield tunnels restricted the high-quality development of urban rail transit in China. Based on the statistical analysis of nearly one hundred cases of tunnels accidents all over the world and focused investigation into 23 typical cases of progressive collapse from 2003 to 2020, the characteristics of progressive collapse of shield tunnels was analyzed. Using statistical methods, the initial damaged location, stratum, damage degree and other factors of shield tunnel progressive collapse accidents and their relationships were categorized and evaluated. The main characteristics were clarified. Based on the comprehensive analysis of multiple cases, the development process of the shield tunnel lining structure damage in the accident was generalized, and it corresponded to the damage degree of the tunnel structure. Finally, considering the interaction between the tunnel structure and the surrounding stratum, the response of the surrounding water and soil during the collapse was analyzed, and it was pointed out that the progressive collapse of the shield tunnels was a fluid-solid coupling dynamic problem. The research results are helpful to improve the relevant understanding of the progressive collapse of shield tunnels, and provide guidance for the prevention and control of the progressive collapse of shield tunnels.

The prevention and treatment of tunnel drainage pipe crystal blockage is very important to the safety of tunnel structure and normal operation of tunnel. Based on the systematic review of domestic and foreign research data, the crystallization process and mechanism of tunnel drainage pipe were analyzed and summarized. The crystallization process in tunnel drainage pipe was summarized as three main stages: the penetration process of groundwater into shotcrete, the dissolution process of calcium in concrete, crystal deposition process in drainpipe. Meanwhile, based on the source of the crystalline material and the crystallization process, the factors affecting the clogging of the tunnel drainpipe were divided into internal and external factors. Internal factors include three types of groundwater quality, surrounding rock types, and shotcrete characteristics. External factors include the characteristics of the aqueous solution in the drainpipe(including the CO₂ content, pH value, salt content in the solution, flow velocity), environmental factors(temperature, pressure)and engineering factors, and elaborated in detail on them. In addition, the prevention technology of drainpipe crystallization blockage was discussed from the aspects of drainage system design, drainage pipe material and concrete mix ratio. Finally, the mechanical, physical, chemical, and biological disposal methods for the crystallization of the tunnel drain pipe were discussed and analyzed in detail. The research can provide a theoretical reference for the prevention and treatment of crystal blocking disease of tunnel drainage pipe.

Based on the analysis of the tunnel TBM construction process and technology, using the three-dimensional geological modeling technology and engineering simulation technology, a construction cycle network simulation model was established, which could achieve the prediction and visual analysis of TBM tunnel construction process. Taking the DXL tunnel project in Tibet as the research object, coupled with the three-dimensional geological model of the DXL tunnel, an optimized analysis of the TBM construction schedule of the DXL tunnel was performed through simulation calculations. The relationship between the completion probability and the construction time was fitted, and the expected completion probability was determined. The construction process was visualized and suggestions to guarantee the construction progress were proposed.

Aiming at the construction safety risk control problem of network construction project in underground space, five network methods including adjacent extension and construction, connection between existed structures extension, vertical direction extension,enlargingexistingunderground extension and multidirectional extension were proposed. The risk characteristics of network construction project were studied and analyzed. In planning and design stage, the safety planning and design methods and pre-redundancy design were established. In construction stage, pre-planning and design methods of quality evaluation,verification and feedback were constructed. The new planning and design technology could guarantee the safety in the whole process of network construction project. Based on the hierarchical control of the interference level, the safety pre-control measures for the four elements in construction projects including the extended structure, the existing structure, the ground and the surrounding environment were put forward. The new construction safety monitoring index system was given so that the safety risk prevention and control could be fully implemented in the construction process. The researched results provided theoretical guidance and technical support for the planning and design and safe construction of underground space network construction project.