# Enlarged Head Pressure-Dispersed Anchor Cable for Foundation Pit Engineering Purposes
## 5 Conclusions  
In order to explore the support effect of the enlarged head pressure-dispersed anchor cable on a foundation pit, we used a foundation pit project in Qinhuangdao City. The present study initially analyzed the internal force distribution law of the anchor cable. Subsequently, in order to verify its anchoring ability, the fluid-structure coupling numerical simulation analysis of the enlarged head pressure-dispersed and enlarged head tension-type anchor cable was carried out using FLAC3D software. The simulation results of the two types of anchor cables were compared with the actual monitoring values and the main conclusions drawn are as follows:  
1. When the plastic zone at the grout-soil interface of anchor cable was penetrated, the end resistance at the variable section enhanced the side resistance. An \"End-pressing inflection point\" was caused by the different increasing speeds of the end resistance and side resistance, and with the increase in the tension, the maximum end resistance can reach 30% of the total tension, and an obvious plastic sphere space appeared at the front of the anchor. 2. In the numerical simulation, the conditions, such as saturated seepage, inclination of anchor cable, excavation of multi-layer soil body and loading at the side of a pit, were considered. By analyzing various conditions of the foundation pit excavation, it was found that the drainage process of the foundation pit increased the horizontal displacement of the support pile and the surface settlement around the foundation pit to a certain extent. The simulation results showed that the displacement results of both the types of anchor cables in this study were within the error range, and the maximum error between the simulation results of the tension-type anchor cables and the engineering monitoring values was only 0.4 mm, which verified the accuracy of the simulation. 3. After excavation, the horizontal displacement of pile body of the enlarged head pressure-dispersed anchor cable was significantly smaller than that of the enlarged head tension-type anchor cable compared with the simulation results of ordinary tension anchor cable. It shows that the displacement of enlarged head pressure-dispersed anchor cable decreases by 24.4%, which indicates that the support effect of the enlarged head pressure-dispersed anchor cable was superior to that of the enlarged head tension-type anchor cable. In general, the axial force of the enlarged head pressure anchor cables was less than that of the enlarged head tension cables, which was possibly due to the excavation depth and properties of surrounding soil  
Figure 25: Pile body displacements. and seepage. Therefore, in regard to the foundation pit support, the support effect of the enlarged head pressure-dispersed anchor cable was better than that of the enlarged head tension anchor cable. There are still many deficiencies in the research on the enlarged head pressure-dispersed anchor cable, such as changing the size of the enlarged head. Further research is needed on the force and deformation laws of the enlarged head and the interaction with the surrounding soil mass. The influence of changing the anchor cable tension at different embedded plates on the enlarged head and the plastic zone of the surrounding soil and the anchoring effect can also be analyzed and studied. Conceptualization, C.W. ; data curation, C.W. and L.K. ; formal analysis Q.G. ; funding acquisition, C.W. and H.C.; investigation, L.K. ; methodology, Q.G. ; project administration, C.W. ; visualization, L.K. and Q.G. ; writing--review and editing, C.W. and H.C. All authors have read and agreed to the published version of the manuscript. This research was financially supported by Natural Science Foundation of Hebei Province (E2020203075), Natural Science Foundation of Hebei Province (E2020203168), Science and Technology Research Project of Colleges, Universities in Hebei Province (ZD2020330), and Qinhuangdao Scientific and Technological Research and Development Plan (202005A001).