苎麻纤维加筋土的强度特性分析

Analysis of Strength Characteristics of Ramie Fiber Reinforced Soil

为改善黏土遇水变形、失水收缩干裂和强度等不良特性,以满足目前的工程需要。以不同长度,不同掺量的苎麻纤维作为加筋材料加入到生土中,通过无侧限抗压和抗剪试验,研究分析加筋材料的长度和加筋率对苎麻纤维加筋土强度特性的影响。当纤维加筋率0.5%,纤维长度15 mm时,苎麻纤维对土样的加筋效果最为显著。与素土相比,苎麻纤维加筋土的应力位移曲线一直持续增长,表现为明显的应变硬化特征;黏聚力值随着纤维掺量的增加而增加,这是因为苎麻纤维在土壤中相互交织、相互连接,形成一个三维空间网络结构,但过长的纤维会使有效纤维长度下降,弱化了加筋效果,苎麻纤维的加筋对土样内摩擦角的影响较小,可以忽略不计。研究结果表明:苎麻纤维能很好地提高试样的无侧限抗压强度和抗剪强度,为苎麻纤维加筋土的理论研究提供参考。

In order to improve the poor engineering characteristics of clay such as water deformation,water loss shrinkage and dry cracking and strength,so as to meet the current engineering needs.Ramie fibers with different lengths and different contents are added to raw soil as reinforced materials.The effects of length and reinforcement ratio of reinforced materials on the strength characteristics of ramie fiber reinforced soil are studied by unconfined compression and shear tests.When the fiber reinforcement rate is 0.5%and the fiber length is 15 mm,the reinforcement effect of ramie fiber on soil samples is the most significant.Compared with plain soil,the stress-displacement curve of ramie fiber reinforced soil has been growing continuously,showing obvious strain hardening characteristics.The cohesion value increases with the increase of fiber content,because ramie fibers are intertwined and interconnected in the soil to form a three-dimensional spatial network structure,but too long fibers will reduce the effective fiber length and weaken the reinforcement effect.The reinforcement of ramie fibers has little effect on the internal friction angle of soil samples and can be ignored.The results show that ramie fiber can improve the unconfined compressive strength and shear strength of the sample,which provides a reference for the theoretical study of ramie fiber reinforced soil.