干湿循环下纤维加筋膨胀土裂隙特性分析

Analysis of crack characteristics of fiber-reinforced expansive soil under wetting-drying cycle

为研究纤维加筋膨胀土的效果和机制,抑制膨胀土脆性开裂,以室内模拟膨胀土为研究对象,通过室内试验及数字图像处理技术,分析干湿循环条件下土体的开裂特性及纤维加筋对裂隙发展的影响。结果表明:膨胀土中掺加纤维,能有效提高土体无侧限抗压强度,且掺量为0.7%时,对土体加筋效果最为显著;在干湿循环条件下,土体表面裂隙发育基本沿原有通道继续展开;随循环次数的增加土体表面裂隙面积率、裂隙总长度逐渐增大,而裂隙平均宽度存在递减趋势,掺加纤维能有效抑制裂隙的开展。研究成果可以为纤维在膨胀土路基工程和边坡防护等实际工程中的设计和施工提供参考。

In order to study the effect and mechanism of fiber reinforced expansive soil and inhibit failure,unconfined compression experiment of the expansive soil was carried out.Image processing technique was used to analyze the cracking characteristics of the soil and the effect of fiber reinforcement on the crack development under wetting-drying cycles.Results show that adding fiber in the expansive soil can significantly improve the soil unconfined compressive strength.When the fiber content is 0.7%the soil reinforcement effect is most significant.Under wetting-drying cycles,the development of soil surface cracks continues to expand along the original channel.With the increase in cycle number,the crack area ratio and total crack length on the soil surface gradually increase,while the average crack width decreases.The addition of fiber in expansive soil can effectively restrain the development of fracture.The results of this research can provide reference for fiber reinforced soil in practical engineering,such as the expansive subgrade,slop protection design and construction.