# Study on Load Transfer Mechanism of Pile-Supported Embankment Based on Response Surface Method
## 3 Analysis of the Numerical Simulation Results
### Single-Factor Test and Results Analysis
#### 3.1.4 Geogrid Strength  
As shown in Figure 9a, with the increase in the geogrid strength, the pile-soil stress ratio gradually increased, but the increasing range gradually decreased. When the geogrid strength reached 120 kN/m, the pile-soil stress ratio did not increase significantly with the increase in the tensile strength. There were two main reasons for this: First, frictional resistance and occlusal force were generated at the interface between the filler particles and geo-reinforced material, which caused tension inside the geogrid and the transfer part of the filler load to the top of the pile; second, the geogrid had a \"lifting effect\" on the upper soil, and the geogrid shared the vertical load and transferred it to the pile top. Therefore, the setting horizontal reinforcement had a certain promotion effect on the load transfer.  
It can be seen from the variation law of the pile-soil differential settlement, as shown in Figure 9a, that although the increase in the grid strength reduced the pile-soil differential settlement to a certain extent, the effect was not obvious. The main reason for this is that the \"lifting effect\" of the horizontal reinforcement reduces the load on the soil between piles, thereby reducing the settlement of the soil between piles. However, the horizontal reinforcement reduces the differential settlement of piles and soil, which affects the soil arching effect. Therefore, the load borne by the soil between piles increases, and the  
Figure 8: Influence of embankment elastic modulus on load transfer. (**a**) variation of pile-soil stress ratio and pile-soil differential settlement; (**b**) variation law of load sharing ratio.  
settlement of the soil between piles increases. Due to the cross-influence of the above reasons, the influence of reinforcement strength on the pile-soil differential settlement was not obvious.  
In contrast, Figure 9b shows that with the increase in the geogrid strength, the load sharing ratio of the membrane effect increased gradually, but the growth rate decreased gradually. The reason for this is that, as the pile-soil differential settlement was basically unchanged, the deformation degree of the geogrid was certain. With the increase in the geogrid strength, the vertical component of the geogrid tension increased, so the embankment load on the soil between piles could be reduced. The geogrid strength continued to increase, but other conditions remained unchanged (such as the embankment load and the pile-soil differential settlement). That is, the embankment load balanced by the membrane effect was basically unchanged, so the growth rate of the load-sharing ratio of the membrane effect decreased.  
In summary, increasing the cohesion, the internal friction angle, and the elastic modulus of the embankment filler can promote the soil arching effect to a certain extent. However,  
Figure 9: Influence of geogrid strength on load transfer. (**a**) variation of pile-soil stress ratio and pile-soil differential settlement; (**b**) variation law of load sharing ratio.  
for pile-supported reinforced embankments, the degree of the load transfer under the combined action of the soil arching effect and the membrane effect was analyzed. Large cohesion, a large internal friction angle, and a high elastic modulus of the embankment reduced the pile-soil differential settlement and the pile-soil stress ratio; the increase in the geogrid strength had a certain promoting effect on the pile-soil stress ratio. However, when the geogrid strength reached 120 kN/m, the increase in the pile-soil stress ratio was small; therefore, in the design of pile-supported embankments, the properties of the embankment filler should be determined according to the reinforcement's form to ensure that the embankment has a high load transfer efficiency.