Ghadr Soheil, Chen Chieh-Sheng, Liu Chih-Hsuan, Hung Ching
Department of Civil Engineering, National Cheng Kung University, Tainan, Taiwan.
Bull Eng Geol Environ. 2022;81(8):317. doi: 10.1007/s10064-022-02810-z. Epub 2022 Jul 16.
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.
对新冠疫情的快速应对导致用过的口罩成为城市垃圾的一种，以用过的口罩（FMs）形式存在的城市垃圾对全球环境构成威胁。为缓解这一问题，该研究探讨了将粉碎的口罩用作沙子中替代增强材料的适用性。采用实验室级渥太华砂和天然采集的海砂作为测试的基础砂。首先检查基础材料和口罩的主要物理特性，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，以评估口罩重量分数、口罩长度和初始有效平均应力对砂的不排水抗剪强度参数的影响。实验结果证明，加入口罩可显著提高砂的不排水抗剪强度；然而，这种提高对初始有效平均应力敏感，初始有效平均应力越低，不排水抗剪强度的增加越高。对于给定的口罩含量，临界状态比和临界状态下的摩擦角随口罩长度增加。最后，结果表明，口罩增强砂表现出剪胀和应变硬化行为。
