**2. Model Test**

#### *2.1. Engineering Background*

The prototype pile of this test is derived from a cantilever anti-slide pile treatment structure located in the inner ring of Nan'an District, Chongqing, China, the upper part of the slope treated by the target anti-slide pile is covered with 0~1 m Quaternary eluvial slope gravelly soil and rock block soil, and the lower bedrock is 56~269 m purple mudstone with quartz sandstone of the Lower Jurassic Zhenzhuchong Formation (J1z). The attitude of the rocks is 289◦∠69◦, and its strike is roughly the same as that of the slope direction, as shown in Figure 1. A total of about 50 cantilever anti-slide piles were designed for the slope protection project (only 15 are shown in Figure 1c). The sectional width and sectional height of the cantilever anti-slide pile section were 1.8 m and 2.7 m, respectively. The pile length was 16.5 m, of which the loaded section and the anchored section were 10.5 m and 6.0 m, respectively, and the pile spacing was 6.0 m. C30 concrete was adopted for the anti-slide pile, and HRB400 steel bars were used for the steel bars of the pile. The tensile steel bars at the rear side of the pile were 42 C( ) 32, and the reinforcement ratio was 0.69%. The structural steel bars at the front side and the steel bars at both sides of the pile were 7 C( ) 25, and the stirrup was 1 C( ) 14 with a spacing of 100 mm, as described in Table 1.

**Figure 1.** Basic information of the target anti-slide pile. (**a**) Location; (**b**) geographic location; (**c**) topographical map; (**d**) realistic picture; (**e**) engineering geological profile.


**Table 1.** Basic parameters of the actual cantilever anti-slide pile.

*2.2. Experimental Design*

2.2.1. Determination of Model Test Similarity

Relying on the above slope as the prototype and considering the conditions of the indoor model field, the model test on the bearing performance of the cantilever anti-slide pile under lateral load was conducted based on the similarity theory. The geometric dimension and the elastic modulus of the anti-slide pile were selected as the control quantities. The similarity relation of geometric dimensions (*Cl*), elastic modulus (*CE*), and the steel ratio (*Cρ*) of the test pile were selected as the basic similarity ratio, and *Cl*, *CE*, *C<sup>ρ</sup>* were defined as 15, 1, and 1, respectively. The dimensional analysis method was used to determine the similarity of other physical quantities, as listed in Table 2.

**Table 2.** Similarity ratio of model test.


2.2.2. Geometric Dimensions and Material Properties of the Test Pile

According to the similarity constants of individual physical quantities in Table 2, the dimensions and reinforcement information of the test pile are presented in Figure 2 and Table 3. The concrete grade of the test pile was determined to be C30, and the thickness of concrete cover was 20 mm. The pile length (*L*) is 1.1 m, in which the loaded section and the anchored section were 70 cm and 40 cm, respectively. The sectional width (b) and the sectional height (h) were 10 cm and 15 cm, respectively. The tensile steel bars at the rear side of the test pile were composed of two steel bars with a diameter of 8 mm (N1), and the steel ratio (*ρ*) was 0.67%. The structural steel bars at the front side of the test pile were composed of two steel bars with a diameter of 6 mm (N2), and the stirrup was composed of one steel bar with a diameter of 6 mm and a spacing of 106 mm (N3).

**Figure 2.** Diagrammatic sketch of the dimensions and section reinforcement of the test piles (unit: mm). (**a**) Dimensions; (**b**) section reinforcement.


**Table 3.** Parameters of the dimensions and reinforcement of the test pile.
