Underground rail transit is a key core infrastructure for alleviating urban surface traffic congestion, promoting national economic development, and building a healthy, green, and harmonious city. The technical safety and quality control of underground rail transit are core factors that determine the efficiency, cost, and availability of urban construction. In soft soil areas, almost all auxiliary passages or underground pump rooms next to underground rail transit tunnels, the entry and exit of shield tunneling, construction of river-crossing or sea-crossing tunnels, and even emergency repairs in case of underground engineering accidents cannot be separated from the application of freezing methods to ensure construction safety. However, the settlement caused by the melting and long-term dynamic deformation of artificially frozen soft soils around these structures poses hidden dangers to the safe operation of subsequent underground rail transit and ground subsidence in the surrounding area. Focusing on this major engineering construction demand, with continuous support from projects such as the National Natural Science Foundation and the Key Technology Research of Shanghai Yangtze River Tunnel Freezing Project, Combining the 'industry-academia-research-application' model, through more than a decade of systematic research, we have broken through a series of bottlenecks brought by traditional deformation theory and created a new theoretical system for the full process (construction period + operation period) deformation settlement control of artificially frozen soft soil with independent intellectual property rights. We have achieved the goal of 'accurate prediction, accurate control, and long-term preservation' of the full process deformation settlement of artificially frozen soft soil, and have made the following important innovative achievements: (1) Established a deformation basic theoretical system that conforms to the characteristics of artificial frozen soft soil's subsidence. By integrating subsidence theory into the consolidation deformation of thick soft soils, we first established a subsidence large deformation consolidation theoretical model based on the subsidence transport characteristics as the consolidation boundary conditions, and proposed a treatment method to confirm the subsidence boundary transport rate through model tests. A new theoretical system that better fits the actual engineering characteristics of subsidence deformation has been constructed. (2) Different subsidence control methods for different freezing modes and time periods have been proposed to optimize on-site monitoring. Guided by the uneven settlement distribution caused by the movement of the freezing front and the redistribution of water during the freezing process around the tunnel, a zoned subsidence control method is suggested; based on the subsidence deformation of artificially frozen soft soil around the tunnel under different stress paths in the later construction phase and underground rail transit operation period, a timed subsidence control approach is adopted. The research breaks away from the traditional monitoring method of post-construction general grouting in China, providing an accurate and controllable method for the subsidence deformation of artificially frozen soft soil, ensuring the safety of the entire underground rail transit system. (3) A new concept of subsidence treatment based on the structural characteristic parameters of frozen-thawed soft soil has been pioneered, that is, by linking the macroscopic and microscopic mechanical behavior of artificially frozen-thawed soft soil. Control the subsidence precisely according to the characteristics of pore structure parameters. By obtaining a temperature field on-site, locate the sections with larger permeability coefficients for anti-seepage treatment to contain the expansion of subsidence deformation, making the subsidence treatment more targeted and time-effective. (4) Establish a dynamic deformation prediction method based on the basic physical and mechanical indicators of artificially frozen soft soil and dynamic load parameters through indoor tests. Combining the subsidence data during construction and long-term dynamic deformation settlement monitoring data during operation, establish a safety and risk control method technology for underground rail transit around the frozen soil layer throughout its entire life cycle. This project is the research accumulation of the research team over more than 10 years, with 44 authorized patents (15 invention patents, 29 utility model patents), 5 registered software, 3 local standards edited in chief, 2 industry standards, and 165 published papers, including 84 SCI/EI-indexed papers, and 4 published monographs. Two sets of research results have been applied in emergency repairs for various side passages or underground pump rooms in subway tunnels, the entry and exit of shielded tunnels, river-crossing or sea-crossing tunnels, as well as accidents in underground engineering projects. The research has successfully optimized the freeze construction and subsequent safety operation monitoring, control, and maintenance of underground rail transit. In the past three years, the added value and technical benefits have reached 400 million yuan, with significant economic, social, and environmental benefits. The project, whether in terms of theoretical system or technological application, reflects that the research results have reached an international leading level. It has important practical engineering value and broad prospects for promotion and application.