为探究常用于隧道减震设计的泡沫混凝土材料在受压荷载下的细观裂纹损伤发展过程以及细观损伤对宏观力学行为的影响，提出基于X-CT成像从细观尺度分析泡沫混凝土损伤过程的模拟方法。首先，借助X-CT扫描技术获取可表征泡沫混凝土细观多孔结构的X-CT图像，并对该图像进行二值化处理以获取用于建立泡沫混凝土细观模型的二值图； 然后，采用自主编译的Python脚本插入内聚力单元模拟泡沫混凝土模型的损伤开裂过程，并分析不同孔隙率下泡沫混凝土的细观损伤变化规律。研究表明： 1）泡沫混凝土应力-应变曲线上升阶段、塑性平台阶段的细观模拟结果与试验结果吻合较好，该方法为研究泡沫混凝土材料的细观损伤机制和宏观力学参数标定提供了新手段； 2）在单轴受压过程中，连接多孔材料相邻孔隙的水泥基充当了“支柱”作用，接触法向压力随着应变积累而连通发展，泡沫混凝土模型受压时主要表现为剪切破坏； 3）当泡沫混凝土孔隙率较低时，其峰值抗压强度会显著增加，但材料可能会在局部产生大规模开裂，孔隙的作用不能得到充分发挥。
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.
