## 1 Introduction  
With the proposal of the \"One Belt, One Road\" plan of China, Guangxi province continues to consider transportation development as a priority, and the construction of transport was continuously hastened. Since the construction of the first high-speed railroad in Guangxi Province in 1997, the expressways in this province have reached 6803 km, and a complex and vast network of highways was built, which has improved the transport capacity. It is necessary to construct highway tunnels for expressways, although different construction methods will have different effects on tunnel construction. [PERSON] et al. [1] compared different construction methods. They also analyzed the stability evolution of different parts of highway tunnel construction and the settlement changes of performing railway tunnels caused by new highway tunnels passing through existing railway tunnels. [PERSON] et al. [2] used the FLAC 3D limited software to carry out a three-dimensional numerical simulation of the tunnel excavation with four construction methods; however, they analyzed the mechanical response law of the rock and supporting structure around the tunnel for various construction methods. [PERSON] et al. [3] carried out numerical simulations using the MIDAS finite software. They analyzed and studied the displacement and stress characteristics of double-arch tunnels for different construction methods. [PERSON] et al. [4] studied the changes in stress and strain during the construction of double-arch tunnels by analyzing different construction methods. [PERSON] et al. [5] studied and analyzed the mechanical behavior of rocks during tunnel construction under different schemes by numerical analysis. [PERSON] et al. [6] studied tunnel deformation, track settlement, and construction reasons.  
With the help of numerical simulation software, it is possible to predict the problems faced during the tunnel excavation project, not only for reference purposes but also to predict, in advance, the various problems that may arise during the excavation, such as over-ex excavation, stress concentration, and excessive deformation around the hole [7; 8; 9]. Thus, the project [10; 11; 12] successfully reduced the number of issues and difficulties faced. The ground settlement caused by the tunnel excavation often leads to damage or destruction of ground buildings, and various numerical analysis methods are used to simulate the effects of ground settlement, to better protect the ground buildings and reduce unnecessary economic losses [13; 14; 15].  
The tunnel excavation will cause a certain surface settlement. This settlement is more complex after the double tunnel excavation. The surface settlement during tunnel excavation mainly contains single tunnel surface settlement, double tunnel surface settlement, shallow-buried layer surface settlement, and deep-buried layer surface settlement [13; 16; 17; 18]. The study of the surface settlement is critical because constructing tunnels will cause some damage to the buildings [19; 20; 21], and the study of settlement plays a crucial role in excavating tunnels and protecting buildings.  
In this paper, based on Gaoliang Tunnel in Guangxi province, constructing the CD, CRD, and full-section methods were analyzed using the finite software. The tunnel vault displacement, deformation around the tunnel, the stress of the initial support and secondary lining, and the law of surface settlement during excavation of deep-buried separate large-section tunnels were studied for different construction methods [22; 23; 24; 25]. However, the tunnel influence law of large section split tunnel excavation was studied by comparing the simulation results with the surveying data. Finally, the prediction formula of the surface settlement curve of the large-section deep-buried double-track tunnel suitable for this project is fitted, which provides an important theoretical basis for similar projects.