## 5 Conclusions  
Combining practical engineering situations, this study uses numerical simulation to compare the differences in the vibration and stress effects caused by two different pile foundation construction methods. Additionally, it explores, debates and puts forward conclusions on the variances in the construction effects attributed to different scenarios within the rotary drilling process. The findings are as follows:  
* Compared with traditional impact pile driving construction, the rotary drilling method for pile foundation construction reduced the horizontal displacement of the pipeline by 90%, the vertical displacement by 10%, the horizontal stress on the pipeline by 85% and the vertical stress by 30%;
* During pile foundation construction, both the horizontal displacement and axial stress of the adjacent oil and gas pipelines are negatively correlated with the construction distance. When the construction distance is less than 5 m, if the horizontal distance continues to decrease, the increase in displacement and stress will be much faster than previously. Therefore, it is recommended that the minimum distance between pile foundation construction and oil and gas pipelines should not be less than 5 m;
* An analysis from the perspective of burial depth shows that the pattern of displacement changes does not exhibit significant alterations as the depth decreases. However, a marked increase in the slope of the stress curve can be distinctly observed once the burial depth is reduced to 2 m. Therefore, in practical engineering projects, when encountering pipelines with a burial depth of less than 2 m, greater attention must be paid to the stress impacts caused by construction. It is noteworthy that with a reduction in the burial depth or a decrease in the horizontal construction distance, the phenomenon of stress concentration on the pipelines becomes more pronounced;
* In the case of pile foundation construction near oil pipelines or important buildings, rotary drilling is preferred if environmental conditions permit. This method can effectively minimize the impact on the surrounding environment and structure and ensure construction safety and efficiency.  
The results of the numerical simulations indicate that when considering both vibration and stress control, rotary drilling pile foundation construction has a clear advantage over traditional impact pile construction in terms of vibration and stress management. This study also summarizes the patterns on how different working conditions affect pile foundation construction. However, this paper has its limitations, lacking related field experiments. If microseismic experiments and vibration monitoring could be conducted, it would be possible to further verify the accuracy of the conclusions. Additionally, the impact of varying geological and weather conditions on vibrations during pile foundation construction is significant, which this study did not take into account.  
Methodology, D.L. and Y.T.; software, X.Z. and Y.J.; validation, X.Z. and Y.J.; formal analysis, X.Z. and K.C.; data curation, X.Z. and K.C.; writing--original draft preparation, X.Z.; writing--review and editing, D.L., K.C. and Y.T.; project administration, D.L. and Y.J.; funding acquisition, D.L. and Y.T. All authors have read and agreed to the published version of the manuscript.  
The research was funded by the Scientific Research Fund of the Hunan Provincial Education Department + 23C0091.  
Not applicable.  
The data that support the findings of this study are available upon request from the authors.  
The authors would like to thank Road & Bridge International Co., Ltd. for their assistance in conducting the study.  
The authors declare no conflicts of interest.