Three-dimensional (3D) printing is an emerging technology capable of producing exact replica specimens in rock mechanics. In this work, the sand 3D printing was explored to model the influence of cyclic freezing and thawing (F-T) for high-porosity weak rocks, which is one of the serious threats to rock stability in a cold region. The evolution of pore structure in the printed specimen during the F-T cycles was interpreted by the nuclear magnetic resonance (NMR) relaxation analysis. A series of Brazilian splitting tests combined with the digital image correlation (DIC) were conducted on these specimens experiencing different F-T cycles. The structural and mechanical degradation of the prepared specimens is reproduced, with a 44.30% increase in porosity and a 39.39% reduction in tensile strength at the end of 10 F-T cycles. Printed specimens deform in a less brittle manner in response to the F-T treatment. The accelerating rate of strain dispersion change was proposed to identify the precursor characteristics during the loading process. The F-T treatment induces the occurrence of precursor earlier than the peak stress, with the precursor stress ratios for the F-T untreated and treated specimens in the ranges of 99.62%–99.75%, and 97.15%–97.93%, respectively. Finally, the mechanical property degradation of fractured rock specimens after the F-T cycles is revealed, and a strong correlation between the mechanical property and the number of F-T cycles that display an exponential decay function is found. The sand 3D-printed specimens are shown to exhibit the changes in the pore structure, mechanical properties, failure pattern, strain distribution, and deformation evolution which resemble high-porosity weak rocks subjected to cyclic F-T.

三维 (3D) 打印是一种新兴技术，能够在岩石力学中制作精确的复制标本。在这项工作中，探索了沙子 3D 打印来模拟循环冻融 (FT) 对高孔隙度软弱岩石的影响，这是寒冷地区岩石稳定性的严重威胁之一。通过核磁共振 (NMR) 弛豫分析解释了 FT 循环期间打印样品中孔结构的演变。对这些经历不同 FT 周期的样本进行了一系列结合数字图像相关 (DIC) 的巴西分裂测试。再现了制备试样的结构和机械退化，孔隙率增加了 44.30%，抗拉强度降低了 39.39%在 10 个 FT 周期结束时。打印的样品响应于 FT 处理以较不脆的方式变形。提出了应变分散变化的加速速率来识别加载过程中的前体特征。FT 处理比峰值应力更早地诱导前驱体的出现，FT 未处理和处理过的试样的前驱体应力比分别在 99.62%–99.75% 和 97.15%–97.93% 范围内。最后，机械性能退化揭示了 FT 循环后的断裂岩石标本，发现力学性能与 FT 循环次数之间存在很强的相关性，显示出指数衰减函数。沙子 3D 打印样品显示出孔隙结构、力学性能、破坏模式、应变分布和变形演化的变化，类似于经受循环 FT 的高孔隙度软岩。