干湿循环对玄武岩纤维加筋膨胀土抗剪强度的影响

Influence of Wetting-drying Cycles on the Shear Strength of Basalt Fiber Reinforced Expansive Soil

为了对膨胀土进行改良,将分散玄武岩纤维掺入膨胀土中,研究干湿循环对玄武岩纤维加筋膨胀土的抗剪强度的影响规律。试验选取长12mm玄武岩纤维,以按纤维含量与干土质量比为0.4%掺入膨胀土中。对膨胀土和纤维加筋膨胀土进行0~3次干湿循环试验,然后对试样进行直接剪切试验,研究干湿循环对玄武岩纤维加筋膨胀土抗剪强度的影响。试验结果表明：玄武岩纤维掺入膨胀土能有效提高膨胀土的抗剪强度。膨胀土和纤维加筋膨胀土经过反复干湿循环后,其强度指标持续降低,且在第一次干湿循环之后抗剪强度降低较明显,之后抗剪强度降低幅度变小。相对于内摩擦角,纤维对黏聚力的增强效果要明显得多。同一次干湿循环,纤维加筋膨胀土比素膨胀土强度的降低幅度小。

To improve the strength of expansive soil, this paper studies the shear strength of fiber reinforced soil with expansive soil which mixed with dispersed basalt fibers. In the study, the ratio of fiber content and dry soil by weight was 0.4% and the length of the fiber is 12 mm. Before the shear tests, the fiber reinforced expansive soil were treated by wetting-drying cycles for 0~3 times. The study results show as follows., the basalt fibers can improve the shear strength of the reinforced soil in the influence of wetting-drying cycles. Whether it is expansive soil or the fiber reinforced expansive soil, shear strength declined with the increase of wetting-drying cycles and the decline reached the maximum in the first cycles, and then gradually mitigated and finally stabilized. Compared to the internal friction an gle, the influence of the fiber reinforcing effect on cohesion is much more obvious. The effects of the basalt fibers in certain range were to restrain the attenuation of shear strength in the same wetting-drying cycles.