溶蚀作用对黄土体物理力学性质影响的试验

(1.西安科技大学 建筑与土木工程学院,陕西 西安 710054; 2.眉山市彭山区住房和城乡规划建设局,四川 眉山 620010)

黄土; 溶蚀; 矿物成分; 强度

Experiment on the effect of rainfall erosion on physical and mechanical properties of loess
YE Wan-jun1,LI Chang-qing1,LI Xiao2,LIU Zhong-xiang1,PENG Rui-qi1,LIU Kuan1

(1.College of Civil and Architectural Engineering,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Housing and Urban Rural Planning and Construction Bureau of Pengshan District,Meishan City,Meishan 620010,China)

loess; dissolution; mineral composition; strength

DOI: 10.13800/j.cnki.xakjdxxb.2019.0408

备注

为了探究雨水溶蚀作用对黄土体物理力学性质的影响,以洛川塬边黄土为研究对象,对试样开展X射线衍射、扫描电镜、强度等试验,对比雨水溶蚀前后试样在粒度组成、矿物成分、离子含量、微结构单元及物理力学性质方面的差异,探究雨水溶蚀作用对黄土工程性质的影响,然后通过显著性理论定量分析溶蚀作用对黄土体损伤程度的大小。试验结果表明:雨水的溶蚀会使土样粉粒含量明显降低,粘粒含量明显增大,亲水性矿物成分降低,土体中Ca2+,Mg2+,SO2-4,CO2-3,HCO-3等离子含量减少; 溶蚀作用前后试样微结构单元发生了明显的变化,具体表现为试样大孔隙减少、小空隙增多,粒间连接减弱; 经历溶蚀作用后试样粘聚力、内摩擦角明显降低,成分的改变造成强度指标降低,进而使得黄土体发生病害; 通过显著性理论分析,溶蚀作用会对土体造成明显损伤。

In order to explore the effect of rain water dissolution on the physical and mechanical properties of loess,the loess at the edge of the Luochuan Plateau is studied by X-ray diffraction,scanning electron microscopy and strength tests.By comparing the differences of particle size,mineral composition,ion content,micro-structure unit and physical and mechanical properties of samples before and after rain water dissolution,the effects of rain water dissolution on loess engineering properties are explored,and then a quantitative analysis is made of the degree of damage caused by rain water dissolution to loess by Significance Theory.The results show that the dissolution of rainwater can significantly reduce the content of silt,clay,hydrophilic minerals and Ca2+,Mg2+,SO2-4,CO2-3,HCO-3 plasma in soil.The microstructural units of the samples changes obviously before and after the dissolution,which is manifested in the decrease of macropores,the increase of small voids and the weakening of intergranular connections.After corrosion,the cohesion and internal friction angle of the sample decrease obviously,and the strength index decreases with the change of composition,which leads to the disease of loess.Through significant theoretical analysis,the dissolution will cause obvious damage to the soil.It can be seen that rainwater erosion has a great impact on the physical and mechanical properties of loess.