## 2 Materials and Methods
### Experimental Design
Deformation gages were strategically positioned, as illustrated in Figure 5. These gauges were evenly distributed across each anchorage section, with the ones in the tensile section affixed to the surface of the steel reinforcement, and those in the compressive section attached to the surface of the steel casing (as the axial force of the anchor body remains constant in the compressive section). To monitor strain changes on both sides of the bearing plate, deformation gages were applied on each side. Additionally, a static strain gauge was employed for strain data collection. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Anchor Name**} & \multirow{2}{*}{**Group Number**} & \multirow{2}{*}{**Anchor Number**} & **Length of Bearing** & **Length of Bearing** & **Length of Pressure** \\  & & & **Section 1 \# (mm)** & **Section 2 \# (mm)** & **Section (mm)** \\ \hline composite & & K-6-1 & 750 & 750 & 1500 \\ anchor & group 1 & K-6-2 & 750 & 750 & 1500 \\  & & K-6-3 & 750 & 750 & 1500 \\ \hline \multirow{2}{*}{tension anchor} & \multirow{2}{*}{group 2} & K-9-1 & 3000 & / 1 & / \\  & & K-9-2 & 3000 & / & / \\  & & K-9-3 & 3000 & / & / \\ \hline \multirow{2}{*}{tension anchor} & \multirow{2}{*}{group 3} & K-11-1 & 4000 & / & / \\  & & K-11-2 & 4000 & / & / \\  & & K-11-3 & 4000 & / & / \\ \hline \multirow{2}{*}{tension anchor} & \multirow{2}{*}{group 4} & K-12-1 & 5000 & / & / \\  & & K-12-2 & 5000 & / & / \\ \hline \hline \end{tabular}  
* \({}^{1}\) / indicates that this type of anchor does not exist in this unit anchoring section.  
\end{table} 
Table 2: Parameters of anti-floating anchors. Figure 4: Load and monitoring device. Figure 3: Field test anchors: (**a**) composite anchor; (**b**) tension anchor; (**c**) anchor arrangement. During the test, strains at different anchorage depths of the anchors were measured, and the axial force distribution curves of the anchors were determined using Equation (1). In the equation, the compressive axial force is represented by \"\(-\)\" and the tensile axial force by \"+\", ensuring a clear distinction between the two. \[N_{ij}=E_{s}A_{si}\epsilon_{ij}+E_{c}A_{ci}\epsilon_{ij} \tag{1}\]  
Equation (1) is defined as follows: \(N_{ij}\) represents the axial force at the first interface of the anchor under load. \(E_{s}\) is the modulus of elasticity of the anchor body or steel casing, and \(A_{si}\) is the cross-sectional area of the anchor body or steel casing at the \(i\)-th section. \(\epsilon_{ij}\) denotes the strain at the \(i\)-th section of the anchor under \(j\)-th load, \(E_{c}\) represents the modulus of elasticity of the grout body, and \(A_{ci}\) is the cross-sectional area of the grout body at the \(i\)-th section of the anchor. The impact of the anchor's weight on its axial force is minor, and is disregarded during the calculation process. Axial force is determined according to Equation (1). The axial force at two measuring points is subtracted and divided by the cross-sectional area to determine the lateral friction resistance of the anchor. The calculation formula is given as Equation (2). To facilitate distinction, the compressive side frictional resistance is designated \"\(-\)\", and the tensile side frictional resistance is designated \"\(+\)\". \[f_{i}=(N_{i}-N_{i-1})/\pi D\Delta L \tag{2}\]  
where \(N_{i}\) is the axial force at the \(i\)-th cross-section of the anchor (kN); \(N_{i-1}\) is the axial force at the \(i\)-th cross-section of the anchor (kN); \(D\) is the anchor diameter, \(D\) = 200 mm; and \(\Delta L\) is the distance between two sections.