Mesoscopic Simulation of Plastic Concrete Based on DEM-flexible Boundary.

To reveal the mesoscopic failure mechanism of plastic concrete, this paper establishes a triaxial test model with flexible membrane boundary to investigate the meso-deformation and failure mechanism of plastic concrete based on PFC-FLAC3D simulation. The empirical function is derived to describe the relationship of the macroscopic uniaxial mechanical strength and triaxial mechanical strength in plastic concrete under different confining pressure by multivariate nonlinear method. The results show that the higher confining pressure restricts the internal particle motion and the shear band shape is more obvious under lower confining pressure. High confining pressure helps to improve the structural integrity and weaken the size effect of compressive strength. As the size of sample increases, the lateral bulging deformation of sample decreases and the particles connect within the oblique section decrease, resulting in the reduction of the X-shaped shear surface. Finally, the multivariate nonlinear fitting method is used to describe the relationship of uniaxial mechanical strength and triaxial mechanical strength under different confining pressure in terms of quantitative, which provides a theoretical basis for subsequent research. [ABSTRACT FROM AUTHOR]