干湿循环作用下麦秸秆加筋黄土强度试验研究

Study on the strength of loess reinforced with wheat straw under drying-wetting cycle conditions

为了探究在干湿循环作用下麦秸秆纤维加筋黄土的力学特性,对素黄土和加筋黄土开展不同干湿循环路径下的无侧限抗压强度试验,得到素黄土和麦秸秆纤维加筋黄土的强度劣化规律,并利用双曲函数对强度劣化度进行拟合,分析干湿循环幅度对强度劣化的影响。试验结果表明:初始含水率较低时,干湿循环作用后黄土的塑性增大,初始含水率较高时,干湿循环作用后黄土的塑性减小;麦秸秆纤维的掺加会显著增强干湿循环作用后的黄土强度,加筋效果最佳的含水率为24%;含水率较低时加筋黄土的最终强度劣化度明显低于素黄土,含水率较高时两者的最终强度劣化度几乎没有差别;加筋黄土的抗压强度劣化对干湿循环幅度更为敏感;在土体破坏时,麦秸秆可以有效阻碍裂缝的开展,继而提高土体强度。

In order to investigate the mechanical properties of wheat straw fiber-reinforced loess,unconfined compressive strength tests were conducted on plain loess and reinforced loess under different dry-wet cycling paths.The strength degradation patterns of plain loess and wheat straw fiber-reinforced loess were derived.A hyperbolic function was then utilized to fit the degree of strength degradation,and the influence of dry-wet cycling amplitude on strength degradation was analyzed.The experimental results indicate that when the initial water content is low,the plasticity of loess increases after dry-wet cycling,while at higher initial water content,the plasticity decreases after cycling;the addition of wheat straw fibers significantly enhances the strength of loess after dry-wet cycling,and the optimal water content for reinforcement being 24%;at lower water content,the final strength degradation of the reinforced loess is significantly lower than that of plain loess,however,at higher water contents,there is little difference in the final strength degradation;the degradation of compressive strength in reinforced loess is more sensitive to the amplitude of dry-wet cycling;wheat straw fibers can effectively mitigate the crack development at the phase of failure,so that enhances the soil strength.