# Research on Lateral Bearing Behavior of Spliced Helical Piles with the SPH Method
## 6 Conclusions  
SPH overcomes the problem of mesh distortion due to large deformations in the numerical simulation, and simulates the time-varying process of the helical pile into the soil by means of smooth particle dynamics. SPH analyses the horizontal bearing characteristics of the spliced pile to the following conclusions:  
1. The horizontal bearing capacity of the screw pile decreases significantly after splicing. The horizontal bearing capacity of the test is 2903 N, and the numerical simulation reaches 3625 N, with an error of 24.87%. The reason for the high error is that the field  
Figure 10: (**a**) The pile installation of progress test; (**b**) Load displacement test of spliced assemblies.  
test environment is challenging to match the simulation, and the soil below the surface contains gravel and residue, which leads to an uneven soil quality. The qualified laboratories can adopt the method of the soil model box, and the soil layer gradient distribution can set more reliable parameters for the established SPH model;
2. The spliced pile is gradually inclined under the loading of the horizontal force, with \(7^{\circ}\) as the end state of the ultimate bearing capacity. The soil particles form a more obvious stress aggregation situation on the surface, which can be divided into three regions with the spliced pile as the center, the stress effect zone at 70.25 mm, near the helical blade, the transition zone at 109.81 mm, and the critical zone at 150.37 mm; the SPH particles are relatively independent. The internal visualization of the pile-soil interaction allows for a single analysis of the particles;
3. The pile-soil model was established in LS-DYNA, perfectly realizing the transition from the pile installation process to the horizontal load bearing. The method of SPH simulated the soil particles at the micro level, showing its unique advantages in pile-soil interaction. From the whole loading process, the soil stiffness changes gradually and finally tends to be stable. The soil under the initial loading is relatively relaxed. With the continuous increase in tension, the soil stiffness shows two apparent changes, and the final displacement increases slowly, reaching the equilibrium state of pile-soil interaction;
4. The model of SPH can be appropriately expanded so that the soil gradually compacts under the action of the horizontal pulling forces rather than due to the boundary effects. Since the horizontal bearing capacity decreases after splicing, can the structure of the cap base be added to the surface? When the soil parameters are measured outdoors, they can be tested in layers at specified depths and added to established SPH models. Since the SPH model is time-consuming, it can be used when it is necessary to analyze the interaction between the pile and the soil accurately; otherwise, the Lagrange method can also be completed.  
Conceptualization, Y.W.; methodology, G.R.; software, Y.T.; validation, Q.Z.; formal analysis, Z.Q.; investigation, W.L.; resources, W.L.; data curation, Z.Y.; writing--original draft preparation, G.R.; writing--review and editing, Y.W.; visualization, Z.Y.; supervision, Y.W.; project administration, Y.W.; funding acquisition, Y.W. All authors have read and agreed to the published version of the manuscript.  
The authors highly appreciate the financial support of this study by Guangdong Water Conservancy Science and Technology Innovation Fund project (No. 2017-31).  
Not applicable.  
The authors would like to thank all the reviewers and editors for their dedication and the Guangdong Water Resources Department for their support.  
The authors declare no conflict of interest.