# Analysis on Response of a Single Pile Subjected to Tension Load Considering Excavation Effects
## 7 Conclusions  
This paper proposed a semi-analytical approach for evaluating the load-displacement behavior of a single uplift pile considering the effects of excavation. The proposed approach evaluated the pile-soil relative displacement caused by excavation before the uplifted load was applied. Thus, the effects of excavation were simulated. A hyperbolic model was used to model the nonlinear interaction of the pile-soil interface. The nonlinear shear displacement of the soil outside the pile-soil interface was introduced to obtain a more realistic load-displacement behavior of an uplift pile. Based on the proposed approach, an effective iterative program was implemented. Comparisons of the results derived from the proposed methods, well-documented field tests, centrifuge tests, and other analytical methods were presented to validate the proposed approach. A parametric study was conducted to investigate the effects of main soil properties on the pile capacity loss caused by the excavation. The main conclusions can be summarized as follows:  
1. The comparisons between the results from the proposed methods, well-documented field tests, centrifuge tests, and other analytical methods showed that the proposed approach was suitable for analyzing an uplift pile considering excavation effects.
2. The soil friction angle has a great influence on the pile uplift capacity loss caused by the excavation. The pile capacity loss decreases linearly with increasing soil effective friction angle. When the effective pile length is equal to excavation depth, the pile capacity loss decreases from 52.5% to 38.9%, with the soil effective angle increasing from 20\({}^{\circ}\) to 35\({}^{\circ}\).
3. The pile uplift capacity loss caused by the excavation is not affected by the soil shear modulus or Poisson's ratio.
4. The pile uplift capacity loss caused by the excavation is related to the ratio of the excavation depth to the effective pile length. The pile capacity loss increases with the ratio of the excavation depth to the effective pile length decreases.  
In this paper, the nonlinear shear displacement of the soil outside the pile-soil interface is considered. Nevertheless, the shear-induced soil shear modulus degradation and soil shear strength caused by principal stress rotation are not considered. Moreover, the proposed method is used for a single pile. A method used to evaluate the pile behavior  
Figure 16: Effects of soil Poisson’s on pile uplift capacity loss with various ratios of excavation depth to effective pile length.  
change of pile groups after excavation should be developed. These shortcomings should be addressed in further study.  
Formula derivation, Z.L.; Data analysis, Z.L. and T.L.; Funding acquisition, S.L.; Project administration, S.L.; Writing--original draft, Z.L.; Writing--review and editing, Z.L. and K.W. All authors have read and agreed to the published version of the manuscript.  
The research was financed by the National Natural Science Foundation of China (Grant No. 41972269), and the Jiangsu Provincial Transportation Engineering Construction Bureau (CX-2019 GC02).  
Not applicable.  
The authors declare no conflict of interest.