## 3 Results
### Load-Displacement Characteristics  
The load-displacement curve of the test anchor is illustrated in Figure 7. The data collection for composite anchor K-6-3 was incomplete due to construction damage during the experiment. Nonetheless, complete data were obtained for the remaining two anchors, as well as for the three tension anchors. The load-displacement curves for all anchors are presented in Figure 7. The anchor failure load, maximum displacement, and failure mode are summarized in Table 3.  
The average ultimate bearing capacities for anchors K-6, K-9, and K-11 were determined as 675, 470, and 611.5 kN, respectively. Notably, anchor K-12 experienced tension-induced rupture, with its ultimate bearing capacity exceeding the ultimate tensile strength value of the anchor body at 715 kN. The ultimate bearing capacity of the composite anchor was 1.44 times that of tension anchor K-9, and 1.1 times that of tension anchor K-11. However, it was lower than the ultimate bearing capacity of tension anchor K-12. By incorporating a steel sleeve and a bearing plate in the middle section of the anchor body via welding, the ultimate bearing capacity of the composite anchor can be effectively enhanced. As a result, its ultimate bearing capacity surpasses that of tension anchors with the same anchorage length, as well as those with an anchorage length of 4 m.  
Figure 6: Damage shape of anti-floating anchors: (**a**) primary loading; (**b**) pull-out failure. Figure 7: _Cont._  
The analysis of anchor head displacement during the failure of the four anchor groups reveals important insights. For anchor K-9, the average anchor head displacement before failure was 14.9 mm. Throughout each loading stage, the displacement of the anchor head consistently increased, demonstrating notable deformation and a strong capacity to adapt to deformation. Similarly, anchor K-11 exhibited an average anchor head displacement of 13.4 mm before failure, with displacement increments comparable to anchor K-9. In contrast, anchor K-12 displayed an average anchor head displacement of 5 mm before failure, with significantly smaller displacement increments compared to both anchor K-9 and K-11. It was observed that as the anchor length increased, the ultimate bearing capacity of the tension anchor also increased. However, the displacement increments under each loading stage gradually decreased. On the other hand, the composite anchor demonstrated an average anchor head displacement of 13.01 mm before failure. Despite achieving an ultimate bearing capacity 1.44 times and 1.1 times greater than the K-9 and K-11 tension anchors, respectively, the composite anchor maintained substantial displacement under each loading stage. This indicates that the composite anchor exhibits enhanced structural ductility while simultaneously improving the ultimate bearing capacity [36]. Figure 7: Load and displacement relationship of anchor: (**a**) K-9; (**b**) K-11; (**c**) K-12; (**d**) K-6; (**e**) total displacement diagram. Figure 7e presents the comprehensive load-displacement curves for the four groups of anchors. The figure reveals interesting observations: when the anchor head load is below 255 kN, the composite anchor exhibits larger displacements compared to the tension anchor at the same load level. However, as the load surpasses 255 kN, the anchor head displacement of the composite anchor gradually becomes smaller than that of tension anchors of the same length. Furthermore, under equivalent load levels, the anchor head displacement of the composite anchor is smaller than that of the K-9 and K-11 tension anchors. This behavior can be attributed to the ability of the composite anchor's compression section to transfer the load to a deeper rock and soil foundation. During the initial load-bearing stage, the composite anchor demonstrates better deformation adaptability. In the later load-bearing stage, the compression section experiences radial deformation under pressure, effectively preventing sudden anchor head displacement.