A New DEM Calibration Method for the Adhesion and Shear Behavior of Clay Materials based on Response Surface Methodology

The Discrete Element Method (DEM) is a commonly used numerical analysis tool for simulating the mechanical behavior of clay materials. DEM models require the specification of microscopic virtual parameters that are not measurable and are not directly related to the macroscopic characteristics of the material. Therefore, calibration of these microscopic virtual parameters is necessary to simulate the mechanical behavior of clay. Calibration typically uses an iterative trial-and-error method, which involves running multiple DEM simulations, making the calibration process computationally expensive. In this work, we propose a calibration method based on Response Surface Methodology for designing virtual direct shear and adhesion shear experiments. This method significantly reduces the amount of numerical simulations required during the calibration process, thus lowering the associated computational cost. Using this approach, the shear stress-strain curve for clay materials was obtained, and a comparison with experimental data shows that the response surface model generated by this method demonstrates high accuracy and reliability. The application of this method to simulate the shear and adhesion behavior of clay represents a novel approach. Validation was performed through a case study of a tunnel boring machine operating in clay, and the predicted results aligned well with the measured data, confirming the applicability of the method. This approach provides effective theoretical support for studying the interaction between clay and machinery.