Considering the convenience of pedestrian transfer, reasonable structural stress and beautiful shape design, most subway stations adopt symmetrical design. At present, the new subway station is developing in the direction of a multidimensional space, as well as a large scale, and complex structure. Tunnel construction also presents unpredictability, coupling amplification and high risks. For example, a subway extension project involves construction, which would affect the normal use of the subway or damage its structure. Based on excavation of the largest underground subway station under construction in China, the Erligou station extension project (line 16 of Beijing Metro), and using theoretical analysis, numerical simulation, monitoring data, and other research methods, this paper quantitatively analyzes the risk of a large space station’s construction process on the adjacent existing station structure and track, as well as highlights key, high-risk sub-projects, or construction steps, combined with specific engineering measures to ensure safety during construction of a new station. The general rules concerning large space subway station construction are further summarized to provide reference for similar projects.

Under the circumstance of soft fractured surrounding rock with high geo-stress, the support technology of tunnel has become a major challenge. Traditional I-shaped steel and bar lattice girder, which cross-sections are often designed to be left-right symmetrical, may have insufficient strength and stiffness. Based on the concept of symmetry, a new support technology of spatial steel tubular grid (SSTG) arch is designed with high strength and large stiffness. In order to clarify the mechanical properties and failure mechanism of SSTG arch used as primary support, through laboratory and numerical experiments, this paper carries out the bending tests for the circumferential joint of SSTG arch components combined with the excavation tunnel project of Panyu Square Station in Guangzhou, and the analyses of the ultimate bearing capacity, deflection displacement, failure modes, and stress–strain evolution laws of joint components are conducted in detail. The results show that during the whole process of loading, the arch components have experienced elastic growth stage, plastic development stage, and final failure stage. The average ultimate bending capacity of SSTG arches is 340.5 kN·m, and the joint opening is 13.9 mm. The joint form of high-strength bolt + rigid flange plate proposed in the paper has reasonable stress state and high safety redundancy, which can bear the load of surrounding rock effectively, and ensure the safety in tunnel construction. The research results could provide a theoretical basis for the design and application of SSTG arch support in related projects.

Using RFPA software, the hydraulic pressure resistance and damage process of the grouted stone body of a tunnel in the high-pressure karst zone were analyzed, and the hydraulic pressure resistance of the composite surrounding rock and composite structure when the tunnel was expanded through the cavern under the effect of hydraulic coupling was investigated. Then, a new parallel heading expansion scheme for the New Yuanliang Mountain Tunnel was innovatively discussed, and the reliability of the results of the calculation model was verified by a field test. Lastly, the model calculation results guided the project to adopt a 5 m grouting range and advanced secondary lining to ensure that the composite structure’s water pressure resistance could reach 3 MPa; by adopting the improved technology of parallel heading expansion based on the CRD method, the safety of tunnel expansion through the cavity was effectively ensured, which can provide a reference for similar projects in the future.

Building deep shafts in water-rich granite formations with large fissures has difficulties, such as high-water pressure and high construction risks, and is prone to water inrush and shaft flooding. This paper relies on the No. 1 vertical auxiliary shaft project of Gaoligongshan tunnel and obtains the uneven distribution of water pressure on the outside of the lining in the horizontal direction through on-site monitoring data. In order to explain this phenomenon, based on the statistical parameters of actual fractures in the field and the Monte Carlo method, the DFN built in FLAC3D6.0 is used to generate a discrete fracture network, and a dual medium model, considering the distribution of large fractures, is established. The reason for the uneven distribution of water pressure is obtained through research: the large fissures in the surrounding rock make the hydraulic conductivity of each part of the stone body formed after grouting of the surrounding rock different. This results in different osmotic pressures from the hydrostatic pressure outside the grouting ring to the outside of the lining through the grouting ring. Based on the distribution characteristics of water pressure outside the lining, the safety of the lining under non-uniform pressure is studied. The lining safety factor is defined as the ratio of the lining’s normal service limit state load to the actual load. The normal service limit state load is the load when the RFPA software is used to establish a load-structure model to simulate the load when the lining has obvious cracks under the action of external load; the actual load is the monitoring load. The new method and mine design code method are used to evaluate the lining safety and make a comparative analysis. The results show that the new method can effectively calculate the lining safety factor and has a larger safety reserve.

In order to solve the problem of testing the water pressure resistance of lining structures of water-rich tunnels and the difficulty of implementing the existing model tests, a large-scale model test method was proposed relying on the New Yuanliangshan Tunnel threatened by high pressure and rich water. This method creatively transformed the external water pressure of the lining structure into internal water pressure, and the conversion coefficient of water resistance of lining under different sizes and loading modes was obtained by numerical calculation. Results showed that the ultimate water pressure resistance of the lining structure under an external uniformly distributed water pressure and local water pressure was 1.44 and 0.67 times of that obtained from the large-scale model tests, respectively. By conducting the large-scale model tests and combining with the conversion coefficient, the water pressure resistance of the actual tunnel lining could be obtained. Research indicated that water pressure resistance of K2.0 (bearing water pressure of 2.0 MPa) type lining at the transition section of karst caves and K3.0 (bearing water pressure of 3.0 MPa) type lining at the section of karst caves of the New Yuanliangshan Tunnel was 3.33 MPa and not less than 4.36 MPa, respectively, and the high reliability of the large-scale model tests was verified by numerical calculation, implying that the model test method could be extended to similar tunnel projects.

On the basis of the theory of unsteady heat conduction, discrete equations for the unsteady temperature field in the secondary linings of high-water-temperature tunnels when considering the hydration heat of lining concrete were derived and established. Spatiotemporal variation in the temperature field of tunnel linings was revealed through the analysis of numerical examples. Research demonstrates that the temperature of the secondary lining within a thickness range of approximately 15 cm near the tunnel clearance decreases sharply under the condition that the lining thickness is 35 cm. The higher the temperature on the lining’s outer surface, the more drastically the lining temperature decreases. When considering the hydration heat of lining concrete, the lining temperature increases to a certain extent after a sudden drop, reaching stability after approximately 20 h, and the lining temperature is approximately 1–2 °C higher than that without taking concrete hydration heat into account. The temperature difference between the tunnel lining’s core and its inner and outer surfaces is positively and negatively correlated with the temperature of the secondary lining’s outer surface, respectively. When the temperature of the secondary lining’s outer surface is not higher than 65 °C, the temperature difference between the tunnel lining’s core and its inner and outer surfaces is less than 20 °C. Conversely, it partially or completely exceeds 20 °C, in which case an insulation method is recommended to utilize to prevent thermal cracks in secondary linings triggered via a high temperature difference.