加筋黄土的动力特性研究

A study on the dynamic characteristics of fiber reinforced loess

以西安市临潼区骊山山前断裂带区域为研究背景,对区域内黄土进行纤维加筋处理。基于正交试验方法设计试验方案,开展加筋土动三轴试验,探讨纤维加筋黄土的动弹性模量差异性,对比分析动弹性模量的影响因素。对正交试验数据结果进行极差分析得出,纤维长度、纤维含量和土体饱和度是影响纤维加筋黄土动弹性模量的三大因素,且三者对其的影响大小顺序为土体饱和度,纤维长度,纤维含量;方差分析得出土体饱和度对玻璃纤维和聚丙烯纤维加筋黄土的显著水平分别是0.035、0.058,土体饱和度对纤维加筋黄土的动弹性模量影响显著,玻璃纤维加筋土和聚丙烯纤维加筋土的优水平均为0.6%的纤维含量、50%土体饱和度、12 mm的纤维长度。研究结果表明,玻璃纤维加筋黄土和聚丙烯纤维加筋黄土的动弹性模量约为无纤维黄土的1.5倍。纤维长度对加筋土动弹性模量的影响呈正相关。玻璃纤维加筋土和聚丙烯纤维加筋土的动弹性模量随纤维含量的变化趋势几乎一致,为先增长后降低。黄土进行纤维加筋处理有助于提升断裂带区域黄土强度,保障断裂带区域工程基础安全建设和运行。

The loess in the Lishan piedmont fault zone in Lintong District of Xi'an City was studied with fiber-reinforced treatment.The dynamic triaxial tests of reinforced loess were carried out based on the orthogonal test plan.The difference of dynamic elastic modulus of fiber reinforced loess was discussed,and the influencing factors were compared and analyzed.Through the range analysis of the orthogonal test results,it is concluded that the fiber length,fiber content,and soil saturation are the three major factors affecting the dynamic elastic modulus of fiber reinforced loess,with an order of soil saturation,fiber length,and fiber content.The results of variance analysis show that the significant levels of soil saturation on glass fiber reinforced loess and polypropylene fiber reinforced loess are 0.035 and 0.058,respectively,indicating that the soil saturation has a prominent effect on the dynamic elastic modulus of fiber reinforced loess.The optimal levels are 0.6%fiber content,50%soil saturation,and 12-mm fiber length for both the glass fiber reinforced soil and polypropylene reinforced soil.The results also show that the dynamic elastic modulus of the two reinforced loess is about 1.5 times that of fiber-free conditions.There is a positive correlation between the fiber length and the dynamic elastic modulus of reinforced loess.Both the dynamic elastic modulus of glass fiber reinforced loess and polypropylene fiber reinforced loess increase first and then decrease with the increase in fiber content.The fiber reinforced treatment of loess is helpful to improve the strength of loess and ensure the safe construction and operation of engineering foundation in the fault zone.