基于分布式应变感测的纤维加筋膨胀土干缩湿胀特性试验

Test on shrinkage-swelling effect of fiber-reinforced expansive soil based on distributed strain sensing technology

为了研究素膨胀土和玄武岩纤维加筋膨胀土在干缩湿胀过程中的应变分布及其裂缝发育规律,试验设计了一个长100 cm、宽7 cm、高5 cm的室内模型钢槽,将传感光纤埋于钢槽中以测量素膨胀土和玄武岩纤维加筋膨胀土应变。基于布里渊光时域分析技术(BOTDA)获得了土体应变分布。结果表明:在膨胀土干缩湿胀过程中,膨胀土模型区域最大收缩应变与含水率之间呈近似线性的负相关。随着含水率的变化,纤维加筋膨胀土应变量和应变变幅均小于素膨胀土的应变量和变化幅度,说明玄武岩纤维显著降低膨胀土的拉伸应变和收缩应变,限制膨胀土的变形和抑制裂缝的发育。

The difference between expansive soil and fiber-reinforced expansive soil in the strain distribution and the development of cracking during shrinkage-swelling cycle were investigated with a model box of 100 cm long,7 cm wide and 5 cm high.The Brillouin optical time domain analysis （BOTDA） was used to monitor the strain distribution of the sensing fibers embedded in the soil.Results indicated that the max value of regional compression deformation was inversely linear to moisture content approximatively during dry-wet cycle.The value of strain amplitude and deformation of fiber-reinforced expansive soil was less than that of expansive soil with the change of moisture content.The basalt fiber could reduce the value of tensile strain and shrinkage strain of expansive soil.In addition,the basalt fiber was useful to restrain the deformation and cracking of soil.