Based on an actual engineering prototype

a 1∶40 secant piled bucket foundation model was designed

and indoor model tests were conducted in homogeneous sand. The bearing capacity of the foundation and the instability mode of the foundation were studied under horizontal bending moment load and vertical load. Finite element modeling and analysis of the same size scaled model were compared. The results showed that： 1） under the action of horizontal bending moment load

the bite pile skirt has good integrity with the internal soil

and the instability mode of the foundation is mainly characterized by large rigid body rotation and a small amount of overall horizontal sliding; The deviation between the ultimate bearing capacity results of the same size model test and finite element analysis during foundation instability is 4.9%. The soil pressure on the rear wall of the cylinder gradually increases

while the soil pressure on the front wall of the cylinder first increases and then decreases. The soil pressure is relatively high at about one-third of the burial depth

indicating that the foundation has undergone translational and rotational movements. 2） Under the action of vertical load

the skirt of the cylindrical foundation and the bearing platform drive the internal soil to deform together

and the foundation mainly undergoes overall shear failure. The deviation between the ultimate bearing capacity results of the test and finite element analysis during foundation instability is 6.05%

and the soil pressure on the cylinder side first decreases and then increases.