Crack Resistance and Strength Properties of Red Clay Modified with Lignocellulose and Guar Gum
Crack Resistance and Strength Properties of Red Clay Modified with Lignocellulose and Guar Gum
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DOI：
10.1007/s12205-023-2005-9
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发表时间：
2023-08
影响因子：
2.2
通讯作者：
H. Fu;Guangxiang Yu;Qianhong Gao;Ling Zeng;Shuo Cao
中科院分区：
文献类型：
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作者：
H. Fu;Guangxiang Yu;Qianhong Gao;Ling Zeng;Shuo Cao
干燥开裂是红粘土在干湿条件下普遍存在的问题。裂缝的存在会降低土体的强度特性，是红粘土边坡浅层破坏的主要原因。本研究的目的是提出一些添加剂，以提高抗裂性，以及红粘土的强度。为此，初步选择了三种天然纤维和三种天然凝胶对红粘土进行改性。进行干燥开裂试验，以确定最佳的纤维和凝胶的抗裂性。然后，对经过最佳纤维和凝胶改性的土样进行直接剪切试验和单轴拉伸试验，以确定提高强度的最佳剂量。结果表明，天然凝胶降低了红粘土的抗裂性，而天然纤维可以提高红粘土的抗裂性。木质纤维素是改善红粘土抗裂性的最佳添加剂，改性效果与纤维掺量呈正相关。在红粘土中加入1.5%的木质纤维素可使红粘土的裂缝率从2.19%降低到0.30%，降低了0.86倍。木质纤维素改性红粘土的抗拉强度、抗剪强度及其参数随木质纤维素掺量的增加呈现先增大后减小的趋势。当木质纤维素最佳用量为0.75%时，剪切强度和拉伸强度分别提高了44.63%和18.21%。木质纤维素和瓜尔豆胶复合改性红粘土的强度与瓜尔豆胶的掺量呈正相关，瓜尔豆胶的最佳掺量为1.0%。在工程实践中，可采用湿红粘土与0.75%木质纤维素和草籽混合作为种植土，在开挖后用喷播机均匀喷洒在坡面上。为了进一步提高种植土壤的强度，可在土壤表面喷洒1.0%瓜尔胶溶液。研究结果可为红粘土边坡的防护提供有益的指导。
Desiccation cracking is a common problem of red clay under wet and dry conditions. The presence of cracks could reduce soil strength properties, which is the major reason for shallow failure of red clay slopes. This study aims to propose some additives to improve the crack resistance as well as the strength of red clay. To this end, three natural fibers and three natural gels were primarily selected to modify red clay. Desiccation crack tests were conducted to identify the best fiber and gel in terms of crack resistance. Then, direct shear tests and uniaxial tensile tests were performed on the soil specimens modified by the best fiber and gel to determine the optimal dosages regarding strength improvements. The results demonstrated that natural gels reduced the crack resistance of red clay, while natural fibers could enhance the crack resistance. Lignocellulose was the best additive in improving the crack resistance of red clay, and the modified effect was positively correlated with the fiber dosage. Adding 1.5% lignocellulose into red clay could reduce the crack rate from 2.19% to 0.30%, with a reduction of 0.86 times. The tensile strength, shear strength and its parameters of lignocellulose-modified red clay showed a trend of increasing first and then decreasing with increasing lignocellulose dosage. At the optimal lignocellulose dosage of 0.75%, the shear strength and tensile strength were increased by 44.63% and 18.21%, respectively. The strength of red clay modified by both lignocellulose and guar gum was positively correlated with the dosage of guar gum, and the desirable dosage of guar gum was 1.0%. In engineering practice, the wet red clay mixed with 0.75% lignocellulose and grass seeds can be employed as planting soil and is sprayed uniformly onto the slope surface after excavation using a spraying planting machine. To further improve the strength of the planting soil, 1.0% guar gum solution can be sprayed on the soil surface. The findings could provide useful guidance for the protection of red clay slopes.