不同改良材料改良黄土试验对比研究

Comparative Study on Experiments of Improved Loess with Different Improved Materials

选取生石灰、纳米二氧化硅和聚丙烯纤维,通过开展直剪、崩解、吸水、水滴入渗和电镜扫描等试验,研究经不同材料处理后的黄土抗剪强度和水敏特性的改良效果和机理.试验结果表明:经不同材料处理后的黄土工程性质发生了不同程度的变化,改良土抗剪强度随着掺入比的增加而增强.经过生石灰和聚丙烯纤维处理后的黄土的耐崩解性得到增强,毛细吸水现象减弱.水滴入渗试验表明三种材料对于黄土斥水性的改良效果不明显.电子显微镜扫描(SEM)图像显示生石灰和纳米二氧化硅主要通过充填、包裹、胶结等方式提高黄土密实度和结构强度,而聚丙烯纤维通过锚固作用形成三维空间网络,与土颗粒形成联锁结构限制土颗粒的相对移动,进而优化黄土的力学特性.本研究为黄土改良在工程中的实际应用提供参考.

Selecting quich lime,nano-silica,and polypropylene fibers,and through the experiments of direct shear,disintegration,water absorption,water droplet infiltration,and scanning electron microscopy,the effects and mechanisms of shear strength and water sensitivity of loess treated with different materials were studied.The test results showed that the engineering properties of the loess changed to varying degrees after being treated with different materials,and the shear strength of the improved soil was enhanced with the increase of the mixing ratio.The disintegration resistance of the loess treated with quicklime and polypropylene fibers was enhanced,and capillary water absorption was reduced.The water droplet infiltration test showed that the three materials did not improve water repellency of the loess significantly.Scanning electron microscope(SEM)images showed that quicklime and nano-silica mainly improved the compactness and structural strength of loess by filling,wrapping,and cementing.While polypropylene fibers mainly formed the three-dimensional spatial network through anchoring and formed the interlocking structure with soil particles to restrict the relative movement of soil particles,and then mechanical properties of the loess were optimized.This study provides a reference for the practical application of loess improvement in engineering.