Abstract: Foam concrete materials are widely used in tunnel vibration damping design. Understanding the development of microscopic crack damage under compressive loading and its influence on macroscopic mechanical behavior is essential. Therefore, the authors propose a simulation method based on X-ray-computed tomography(X-CT) imaging to analyze the damage process from a macroscopic perspective. First, X-CT imaging is employed to capture the cellular structure of foam concrete, followed by binarization to generate a binary map for constructing a mesoscopic model. A custom Python script is integrated into the cohesive force unit to simulate the damage and cracking process of the foam concrete model. The microscopic damage behavior under varying porosities is further investigated. The results indicate the following: (1) The simulated stress-strain curves during the rising and stable stages align well with the experimental data, offering a novel approach for understanding the detailed damage mechanisms and calibrating the macro-mechanical parameters of foam concrete. (2) During uniaxial compression, the cementitious matrix linking adjacent pores acts as a "pillar", with the contact normal pressure increasing as strain accumulates and connectivity develops. Foam concrete primarily exhibits shear-induced damage under compression. (3) Lower porosity significantly enhances the peak compressive strength; however, the material may develop extensive local cracks, preventing optimal utilization of the pore space.

Key words: foam concrete, X-ray-computed tomography imaging, microscopic damage simulation, cohesive element