## 3 Analysis of Torque Load Transfer Mechanism
### Comparative Analysis of Test Results  
The shear stress in the foundation rings of the four specimens under the torque load was analyzed, and the variation in torsional shear stress in each specimen was obtained. The changing trends of shear stress in each specimen under the torque load were compared, as shown in Figure 16.  
Figure 16: Torque load sharing ratio of the four specimens.  
Figure 15: Torque load sharing ratio of specimen ZT-4.  
Under the torque load, the characteristics of shear stress in the foundation ring of the four specimens were more consistent, which can be divided into the following three stages.  
1. Growth stage: within 0.2-0.5 \(T\), the shear stress shared by the foundation ring of each specimen fluctuated slightly, which was a common characteristic at the initial loading stage. Nevertheless, the growing trend was relatively rapid as a whole.
2. Mitigation stage: within 0.5-1.1 \(T\), the growing rate of the shear stress sharing ratio (60-95%) of the foundation ring in each specimen slowed down.
3. Stationary stage: within 1.1-1.5 \(T\), the shear stress sharing ratio (75-90%) of the foundation ring in each specimen tended to be stable, with an average value of about 80%.  
Experimental results show a certain degree of dispersion, especially at the initial loading stage. This is due to two reasons. First, the torque load itself was too small. Second, the concrete material itself had greater dispersion, even though the four concrete experimental scale models were made and poured in the same batch. However, the overall trends of experimental results were relatively consistent, reflecting the influences of various parameters on the torque load transmission. The torque load shared by the foundation ring fluctuated initially and tended to be stable afterward.  
The torque load was mainly sustained by the foundation ring and further transferred downwards, while only a small part was sustained by the top radial reinforcement. At the stationary stage, after the width and thickness of the bottom flange were both reduced by 13%, the torque load sharing ratio of the foundation ring decreased most obviously. On the contrary, the effects of the reduction in the foundation ring depth and strength grade of the base concrete were not obvious. The top radial reinforcements shared about 15-22% of the torque load, most of which were sustained and further transferred by the foundation ring. This part of the torque load had less effect on the force in the top radial reinforcement.  
During this experiment, only the vertical self-weight load and torque load were applied. In order to study the transmission path of the torque load in the foundation by only one single factor, template paint and lubricant were applied to the sidewall of the foundation ring during its fabrication. However, even after this treatment, there was still a certain amount of adhesion and friction therein. Therefore, at the early and middle stages of torque loading, most of the torque was borne by the residual cohesive force of the sidewall and the top radial reinforcement, while the torque load transmitted to the bottom anchor flange of the foundation ring was relatively small. With the continuous increase in torque load, after gradually eliminating the bonding force between the sidewall of the foundation ring and the residual concrete, the torque load transferred to the anchor flange at the bottom of the foundation ring gradually increased.