## 3 Results
### Side Friction Distribution  
As shown in Figure 9, the graph illustrates the distribution of side friction resistance along the depth of the anchor. The side friction resistance of the anchor rod gradually decreases as the anchoring depth increases. While the upper anchoring segment of the anchor fully utilizes its lateral friction resistance, the lower anchoring segment experiences insufficient lateral friction resistance. This deficiency results in local stress concentration in the upper anchoring section, leading to premature failure in that area and subsequently extending to the lower anchoring section, causing overall anchor failure. The lateral frictional resistance of the upper and lower anchoring sections of the anchor cannot effectively function simultaneously. By analyzing the effective lateral frictional resistance of three sets of tensioned anchors, it was determined that the maximum lateral frictional resistance of anchors K-9, K-11, and K-12 is 0.4, 0.3, and 0.27 MPa, respectively. Although the ultimate bearing capacity of the tensioned anchor increases with anchor length, the degree of lateral frictional resistance decreases.  
As shown in Figure 9d, The lateral friction resistance of the composite anchor exhibits a three-stage distribution. The absolute values of lateral friction resistance for all three anchor units exceed 0.3 MPa, with the lateral friction resistance on the bearing Section 1 # side reaching 0.6 MPa or higher. In the pressure-bearing section and the two-unit anchorage section of the tension-bearing section, the absolute value of lateral frictional resistance is approximately 0.4 MPa, with the highest value observed. The peak value of lateral frictional resistance gradually increases with increasing load for both composite anchors and tension anchors, while the position of the peak value remains relatively constant. As the load increases, the lateral frictional resistance gradually extends downward along the depth distribution [43].  
The lateral frictional resistance of the lower anchorage section of the tensioned anchor is consistently lower than that of the lower anchorage section of the composite anchor, and the degree of lateral frictional resistance decreases with increasing anchorage length. The overall degree of lateral frictional resistance exerted by the three anchoring units in a composite anchor is higher than that of a tension anchor, resulting in a larger range of lateral frictional resistance. This is attributed to the shorter length of each anchoring segment, which reduces the bond softening effect and enables more effective utilization of the soil strength within the anchoring segment, consequently improving the ultimate bearing capacity of the anchor [7].  
The lateral friction resistance proves equally effective in the anchored sections of the compression section and the tension section, as the load transmitted to these sections is evenly distributed by the bearing plate to both sides. This effectively prevents local stress concentration, facilitates more efficient utilization and uniform distribution of the lateral friction resistance of the anchor, and serves as a key factor in enhancing the ultimate bearing capacity of the composite anchor.