冻融作用下聚丙烯纤维土力学性能试验研究

Experimental Study on Mechanical Properties of Polypropylene Fibers Soil under the Freezing and Thawing

为研究冻融作用对聚丙烯纤维土力学性能的影响规律,通过正交试验以及极差方差显著性分析,得到了纤维掺量、纤维长度、冻融循环次数3个因素对于聚丙烯纤维土抗剪强度和无侧限抗压强度的影响规律,确定冻融作用下聚丙烯纤维土最佳组合方案为:纤维长度为9 mm、纤维掺量为3‰。最佳组合方案下的纤维土粘聚力较素土有一定的提升,且提升效果随冻融次数的增加更为显著;内摩擦角随冻融次数的增加出现了先增大后减小的现象,在冻融3次以后,掺入最优组合方案的纤维土内摩擦角较素土要小;无侧限抗压强度的提升最为显著,增强效果随着冻融次数的增加变弱。

Orthogonal experiment and extreme difference significance of variance analysis were carried out in order to study the influence of freezing and thawing on soil mechanics performance of poly- propylene fiber,which results in the effects of fiber content, fiber length, freezing and thawing cycles for polypropylene fiber soil shear strength and unconfined compressive strength. The best combination of poly- propylene fiber soil under the effect of freezing and thawing：fiber length is 9mm,fiber dosage is 3‰ was determined. Under the best combination scheme the fiber soil cohesive strength compared with plain soil is improved, and the effect is more significant with the increase of the number of freezing and thawing ;the angle of internal friction with freeze-thaw cycles increases appeared to increase first and then decreased, after the freeze-thaw 3 times, the internal friction angle of Optimal combination scheme of fiber soil com- pared with plain soil is smaller ;the promotion of unconfined compressive strength is the most significant, the effect with the increasing times of freezing thawing cycle becomes weak.