复掺非等长玄武岩纤维的水泥土抗拉特性分析

为研究非等长玄武岩纤维复掺对水泥土抗拉强度的影响规律,选取长度为6,9,12 mm的玄武岩纤维混合复掺,开展不同长度玄武岩纤维复掺的水泥土拉伸试验和电镜扫描测试,分析纤维复掺对水泥土抗拉峰值强度、残余强度及韧性的影响规律及其微观作用机制。结果表明:玄武岩纤维复掺水泥土的应力-应变曲线均可划分为弹性变形阶段、损伤破坏阶段、残余强度阶段和最终破坏阶段4个阶段,纤维减缓了试件在损伤破坏阶段的应力损失速度; 复掺不同长度的纤维可有效提高纤维水泥土的抗拉峰值强度、残余强度和韧性; 纤维长度9 mm+12 mm按3:1混合复掺的抗拉强度、残余强度最优; 纤维在水泥土中相互搭接交错形成空间网状结构,纤维与水泥土间的锚固是其提升水泥土抗拉强度的主要机理; 纤维短时易被拔出,纤维过长会出现集束现象,影响纤维对水泥土抗拉强度的增强效果。

Analysis on Tensile Properties of Cemented Soil Compounded with Unequal Length Mixed Basalt Fiber

In order to investigate the influence and strengthen mechanism of unequal length mixed basalt fiber on the tensile strength of cemented soil, fibers with length of 6,9,12 mm were selected to mixed. Uniaxial tensile test and scanning electron microscope test were carried out to investigate the variation laws and the micro-mechanism of peak tensile strength, residual tensile strength and toughness of cemented soil. The results show that the tensile stress-strain curves of cemented soil with fiber can be divided into four stages: elastic deformation stage, damage and failure stage, residual strength stage and final failure stage. During the damage and failure stage, the fiber slows down the stress loss rate of cemented soil. The peak tensile strength, residual tensile strength and toughness of cemented soil can be improved effectively by adding different lengths of basalt fiber. The peak and residual tensile strengths of cemented soil with 9 mm and 12 mm length mixed by 3:1 ratio are the highest. Fibers are overlapped and staggered in cemented soil to form a spatial network structure. The anchorage between fibers and cemented soil is the main mechanism to improve the tensile strength of cemented soil. When the fiber length is short, it is easy to be pulled out, and if the fiber length is too long, there is cluster phenomenon, which affects the enhancement effect of fiber on the tensile strength of cemented soil.