# Experimental Study on the Effect of Pile-End Soil on the Pile Load Transfer Law
## 3 Analysis of Test Results  
### Load Displacement Relationship  
According to the test results, the load-displacement curves (Q-s curve) of the pile-end soilless compressive pile and the conventional compressive pile are plotted as shown in Figure 4.  
From Figure 4a, it can be seen that the Q-s curve of the pile-end soilless compressive pile shows a slow-steep type. When the load is less than 13.35 kN, the pile-top settlement is small, and the settlement varies approximately linearly with the increase of the load. As the load increases, the Q-s curve gradually bends, and the settlement rate increases, showing a nonlinear change. When the load is greater than 40.05 kN, the settlement rate of the pile top increases rapidly, and the Q-s curve shows a steep drop point at 45.39 kN. The cumulative settlement of the pile top is 4.31 mm. Figure 4b show the Q-s curve of the conventional compressive pile, which is consistent with the trend of the curve of the pile-end soilless compressive pile, and the curve shows a slow-steep type. When the load is less than 21.32 kN, the pile top settlement is small. As the load increases, the Q-s curve  
Figure 4: Q-s curve of test pile: (**a**) the pile-end soilless compressive pile and (**b**) the conventional compressive pile. Figure 3: Schematic diagram of test pile loading: (**a**) the pile-end soilless compressive pile and (**b**) the conventional compressive pile. gradually bends, and the settlement rate of the pile top increases, showing a nonlinear change. When the load is greater than 53.3 kN, the settlement rate of the pile top increases rapidly, and the Q-s curve shows a steep drop point at 58.63 kN. The cumulative settlement of the pile top is 4.34 mm. The overall performance of the Q-s curves of the two test piles is relatively consistent, and the Q-s curves can be divided into three stages: the linear stage, the local shear stage, and the failure stage. For the pile-end soilless compressive pile, when the load is in the range of 0-10.68 kN, the Q-s curve is approximately a straight line, showing that the pile body is in a linear stage. When the load is in the range of 13.35-40.05 kN, the Q-s curve changes nonlinearly, the pile top settlement increases significantly, and the soil around the pile gradually changes nonlinearly, showing that the pile body is in the local shear stage. When the load is in the range of 42.72-48.06 kN, the pile top settlement increases rapidly, and when the soil around the pile is damaged, the pile displacement will increase sharply, and the whole pile slides downward, at which time the pile is in the failure stage. Similarly, the conventional compressive pile is divided into three stages: When the load is 0-15.99 kN, it is the linear stage. When the load is 21.32-53.3 kN, it is the local shear stage. When the load is 58.63-63.96 kN, it is the failure stage. Different from the pile-end soilless compressive pile, when the conventional compressive pile is in the failure stage and the soil at the end of the pile is damaged by compression, the pile displacement will increase sharply, and the whole pile will slide downward. Based on the measured data, the s-lgt curves of the two test piles under different static loads were obtained, as shown in Figure 5.  
From Figure 5a, after the pile-end soilless compressive pile was loaded to 48.06 kN, the pile top settlement suddenly increased to 8.12 mm, and the soil around the pile was damaged. Combined with Figure 4a, 45.39 kN was the ultimate bearing capacity of the pile-end soilless compressive pile. From Figure 5b, after the conventional compressive pile was loaded to 63.96 kN, the pile top settlement suddenly increased to 10.13 mm, and the pile-end soil was damaged. Combined with Figure 4b, 58.63 kN was the ultimate bearing capacity of the conventional compressive pile.