The rapid response to the COVID-19 pandemic has resulted in increased municipal waste in the form of used face masks (FMs), which pose a global threat to the environment. To mitigate this, the study explores the applicability of shredded FMs as alternative reinforcing material in sands. Laboratory-grade Ottawa sand and naturally collected sea sand are adopted as the base sands for testing. The primary physical properties of the base materials and the FMs are first examined, and the soil particles are imaged via scanning electron microscopy. Thirty consolidated undrained (CU) triaxial compression tests were conducted to evaluate the effects of the weight fraction of FM, FM length, and the initial effective mean stress on the undrained shear strength parameters of the sands. The experimental results proved that FM inclusion can lead to a substantial improvement in the undrained shear strength of the sands; however, such improvement was sensitive to the initial effective mean stress, with higher undrained shear strength gains associated with lower initial effective mean stress. For a given FM content, the critical state ratio and angle of friction at the critical state increased with the FM length. Finally, the results revealed that FM-reinforced sands exhibit dilative and strain-hardening behaviors.

对 COVID-19 大流行的快速反应导致使用过的口罩 (FM) 形式的城市垃圾增加，这对全球环境构成威胁。为了缓解这种情况，该研究探讨了将碎 FM 作为砂中替代增强材料的适用性。采用实验室级渥太华沙和自然采集的海沙作为测试基砂。首先检查基础材料和 FM 的主要物理性质，并通过扫描电子显微镜对土壤颗粒进行成像。进行了 30 次固结不排水 (CU) 三轴压缩试验，以评估 FM 的重量分数、FM 长度和初始有效平均应力对砂体不排水抗剪强度参数的影响。实验结果证明，FM夹杂物可以显着提高砂体的不排水抗剪强度；然而，这种改进对初始有效平均应力很敏感，较高的不排水剪切强度增益与较低的初始有效平均应力相关。对于给定的 FM 含量，临界状态比和临界状态下的摩擦角随着 FM 长度的增加而增加。最后，结果表明，FM 增强砂表现出膨胀和应变硬化行为。临界状态比和临界状态摩擦角随着FM长度的增加而增加。最后，结果表明，FM 增强砂表现出膨胀和应变硬化行为。临界状态比和临界状态摩擦角随着FM长度的增加而增加。最后，结果表明，FM 增强砂表现出膨胀和应变硬化行为。