Abstract: The mechanical properties of the pile-soil interface are a crucial issue that affects the safe construction and healthy operation of pile foundations. Analyzing these properties is an essential step to uncovering the deformation and bearing capacity mechanisms of the pile foundation. Therefore, this paper developed a pile-soil interface mechanical properties model test system, which uses PLC automation control technology to control the vertical loading rate and displacement. The system also considers different ground settlement states, moisture content, and complex loading conditions. To verify the reliability and effectiveness of the test system, the mechanical properties of the pile-soil interface during the penetration process of a red clay pile with different moisture contents were analyzed and compared with numerical simulation results. The results revealed that the unsaturation of the soil significantly increases the soil pressure and unit lateral friction of the pilesoil interface. The test results agreed well with the numerical simulation results. This model test system can provide experimental support and theoretical references for pile foundation engineering practices.

Key words: Pile Foundation, Model Testing, Numerical Simulation, Static Pressed Piles, PileSoil Interface Mechanical Properties