# Prediction of Surface Deformation Induced by Ultra-Shallow-Buried Pilot Tunnel Construction
## 5 Conclusions  
1. It is proposed that the ground surface settlement induced by ultra-shallow-buried excavation consists of two components: uniform soil shrinkage and the non-uniform deformation of the initial support. Based on this, the calculation formula for ground surface settlement caused by the excavation of a horseshoe-section pilot tunnel is derived.
2. The calculation model proposed in this study applies to diverse geological conditions and construction methods, enabling the accurate prediction of surface settlement from  
Figure 19: Horizontal surface displacement of Beijing Pilot Tunnel.  
Figure 20: Horizontal surface deformation of Beijing Pilot Tunnel.  
shallow tunnel excavation. Taking the Kunming Railway Transit Phase I and Xi'an Metro Line 8 shallow tunnels as cases, compared with the equivalent cross-section calculation model, the direct use of the horseshoe-shaped cross-section model reduces errors by 50%, significantly enhancing prediction accuracy.
* The computational model proposed in this study for surface deformation induced by the excavation of an ultra-shallow-buried pilot tunnel on Beijing Rail Transit Line 13 demonstrates good correlation with the measured data. It is found that under ultra-shallow burial conditions, significant ground surface heave occurs at 2.5 times the width from the pilot tunnel center. The cross-section settlement curve overall trends show maximum settlement above the excavation center, followed by a rapid decrease in settlement toward the edge, which transitions to heave, after which the heave rapidly diminishes.  
Conceptualization, C.L. and Y.S.; methodology, X.G. and P.J.; software, X.G.; validation, C.L. and Y.S.; formal analysis, P.J.; investigation, Y.Y.; resources, X.L. and Y.S.; data curation, Y.Y. and P.J.; writing--original draft preparation, X.L. and X.G.; writing--review and editing, P.J. and Y.Y.; visualization, X.G. and Y.Y.; supervision, C.L. and P.J.; project administration, X.L. and P.J.; funding acquisition, C.L. and Y.S. All authors have read and agreed to the published version of the manuscript.  
This research was funded by China Railway First Group Second Engineering Co., Ltd. and Beijing Jiaotong University, under the collaborative project entitled \"Study on Settlement Control of Ultra-Shallow-Buried Tunnel-Excavated Stations on Beijing Metro Line 13\" (Project Code: C24L01730). The APC (Article Processing Charge) was also funded by this project.  
The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.  
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. [PERSON], [PERSON] and [PERSON] are employees of China Railway First Group Second Engineering Co., Ltd. The authors declare that this study received funding from China Railway First Group Second Engineering Co., Ltd.  
The following abbreviations are used in this manuscript:  
PBA  
Pile-Beam-Arch method  
**List of Symbols**  
**Symbol**  
**Definition**  
_X,Y,Z_  
coordinates of Cartesian coordinate system  
m  
coordinates of local Cartesian coordinate system  
m  
burial depth of micro soil element or tunnel section  
m  
micro soil element  
\(f\)  
probability density function