聚丙烯纤维掺量对水泥土强度特性的影响研究

Effect of polypropylene fiber content on strength properties of cement soil

水泥固化土中掺入聚丙烯纤维,可以对土体强度进行一定的改良。本文以聚丙烯纤维掺量为研究变量,掺入0%、0.1%、0.2%、0.4%的9mm长纤维和15%水泥,制备纤维水泥土,通过无侧限抗压强度试验和常规三轴试验,分析了聚丙烯纤维掺量对水泥土强度特性的影响。试验结果表明:纤维水泥土的无侧限抗压强度随纤维含量的增加而增强,纤维含量对纤维水泥土无侧限抗压强度的提高效果很明显。28d龄期掺入0.4%纤维的水泥土,其无侧限抗压强度是不掺纤维水泥土的1.60倍。纤维的掺入能提高水泥土的峰值应力和增大破坏应变,并且随纤维含量的增加,水泥土的粘聚力逐渐增大,而其内摩擦角却变化不大。纤维水泥土在受压过程中,纤维的掺入能够为土体提供一定的拉应力,从而能在一定程度上阻止试样裂缝的开展。

The soil strength can be improved by mixing polypropylene fiber into the cement solidified soil,in this article,the mixing amount of polypropylene fiber is selected as the variable,by mixing 0%,0. 1%,0. 2%,and0. 4% of fibers that are 9 mm in length and 15% cement,the fiber-cement soil is produced. By carrying out the unconfined compressive strength experiment and conventional triaxial test,the influences of polypropylene fiber mixing amount on cement soil strength are analyzed. The experiment results show that： the unconfined compressive strength of the fiber-cement soil increases along with the increasing of fiber content,the fiber content presents significant enhancing effect on the confined compressive strength of fiber-cement soil. 28-day aged fiber-cement soil with 0. 4% fiber mixing content shows a 1. 6 times higher unconfined compressive strength than the cement soil without fiber mixing. The mixing of fiber improves the peak stress of the cement soil as well as the breaking strain,and with the increase of fiber content,the cohesion of cement soil gradually increases,and its internal friction angle has not changed much. In the compression process of fiber cement,the fiber can be incorporated into the soil to provide a certain amount of tensile stress,which can prevent the development of sample cracks in some degree.