The transfer section between the cross passage and the main tunnel is the part that needs to be paid attention to during the underground excavation construction of the subway. Due to complex stress, the collapse of the horsehead gate and excessive surface settlement often occur. In order to determine the construction scheme of the transfer section between the cross passage and the main tunnel of Guanshui Road Station of Metro Line two in Guiyang, China, the numerical simulation method was used to analyze the “double-holes interval pillar method,” “sector expansion method,” and “gate climbing method,”, respectively. The mechanical response of the surrounding rock and supporting structure under each method was compared. The comparisons showed that the surface settlement, the displacement of the cave, and the plastic zone caused by the double-holes interval pillar method were the smallest, and the method can reduce the construction risk, shorten the construction period, and reduce the project cost. Therefore, it was recommended to use the double-holes interval pillar method to construct the transfer section. The comparison between the measured data and the numerical simulation results of the double-holes interval pillar method showed that the numerical simulation results were smaller than the measured data at each point, and the surface settlement and horizontal displacement in the tunnel both met the safety control standard.

The Chongqing metro line 6 underpass expressway around the city is taken as an engineering background, and the optimal excavation sequence and corresponding control countermeasures for the triangular-distributed three-line metro tunnel underpass expressway are studied. The influences of excavation sequence on the tunnel surrounding rock deformation, surrounding rock stress, supporting structure stress, plastic zone, and surface settlement are analyzed by using MIDAS/GTS NX finite element software. The numerical simulation results showed that Case 1 is the optimal excavation sequence of the metro tunnel. However, the surface settlement under the optimal excavation sequence exceeds the limit value of 30 mm, which cannot guarantee the safety of expressway traffic. On this basis, the control measure for strengthening the three-line tunnels with advanced small pipe grouting and reinforcing the middle tunnel with concrete-filled steel tube piles are proposed. Moreover, the excavation process of the metro tunnel with and without reinforcement schemes is numerically simulated. The results show that the reinforcement scheme can effectively control the surface settlement value within the limited value (16.47 mm), which is close to the maximum surface settlement of 18.31 mm after the metro tunnel excavation is completed, indicating that the proposed reinforcement scheme is beneficial to ensure the safety of metro tunnel construction and the driving safety of the expressway.