PP纤维–粉煤灰改良黄土抗剪强度试验研究

Experimental Study on the Shear Strength of PP Fiber-Fly Ash Modified Loess

摘要: 为研究在冻融循环条件下影响聚丙烯纤维–粉煤灰改良黄土的因素；探究粉煤灰掺量和PP纤维掺量对冻融循环作用下黄土抗剪强度特性的影响，并建立黏聚力和内摩擦角估测模型。实验结果表明：粉煤灰掺量和PP纤维掺量的增加，能显著提高土体抗剪强度。粉煤灰掺量为20%和PP纤维掺量为0.5%时的改良黄土抗剪性能最优。随着粉煤灰和PP纤维掺量的增加，内摩擦角和黏聚力先增后减，其中黏聚力增长较为显著，最大增幅分别为22.4%和15.1%，内摩擦角增幅均相对较小。基于此，建立考虑PP纤维与粉煤灰掺量影响的PP纤维–粉煤灰改良黄土抗剪强度参数预测模型，为季冻区改良黄土路基工程设计提供参考。

Abstract: To study the factors affecting the improvement of loess by polypropylene fiber-fly ash under freeze-thaw cycle, the effects of fly ash content and PP fiber content on the shear strength of loess under freeze-thaw cycle were investigated, and the models for estimating cohesion and internal friction Angle were established. The experimental results show that the increase of fly ash and PP fiber content can significantly improve the shear strength of soil. When fly ash content is 20% and PP fiber content is 0.5%, the shear resistance of improved loess is the best. With the increase of fly ash and PP fiber content, the internal friction Angle and cohesion increased first and then decreased, and the cohesion increased significantly, with the largest increases of 22.4% and 15.1%, respectively, and the internal friction Angle increased relatively little. Based on this, a prediction model of the shear strength parameters of PP fiber-fly ash improved loess was established, which considered the influence of PP fiber and fly ash content, and provided a reference for the engineering design of improved loess roadbed in seasonal freezing area.