含水率对黄土微观结构的作用效应分析

Effect of water content on loess microstructure

黄土作为一种特殊岩土,其结构特征决定着工程力学特性。以朔州经济开发区市政路网及配套市政管线工程中所遇到的黄土为研究对象,采用扫描电镜方法,从微观角度研究不同含水率对黄土微观结构的作用效应。研究结果表明:①原状黄土骨架颗粒表面及边缘呈现不规则断口,颗粒之间呈阶梯状分布,棱角分明,空隙较大,粘连度较低。大颗粒表面多存在粒状、板状的细粉粒;②随着含水率的增加,首先发生变化的为颗粒大小,在水分子的作用下,大颗粒不断吸引小颗粒粘结形成了大量的板状大颗粒,小颗粒的数量呈减小趋势;③含水率的增加会使黄土颗粒大孔隙不断减少,形成以小孔隙为主孔隙状态;④含水率的增加会使黄土颗粒之间变得更加密实,颗粒之间的粘结相含量也在增多。

As a special rock and soil,the structural characteristics of loess determine the engineering mechanical properties.Therefore,this paper takes the Loess encountered in the municipal road network and supporting municipal pipeline project of Shuozhou Economic Development Zone as the research object,and uses the scanning electron microscope method to study the effect of different water content on the microstructure of loess from the microscopic point of view.The results show that:①the surface and edge of undisturbed loess skeleton particles show irregular fracture,the particles are distributed in steps,with clear edges and corners,large gap and low adhesion.There are many granular and plate-shaped fine powder particles on the surface of large particles.②With the increase of water content,the first change is the particle size.Under the action of water molecules,large particles continue to attract small particles and bond to form a large number of plate-like large particles,and the number of small particles decreases.③The increase of water content will continuously reduce the macropores of loess particles and form a pore state dominated by small pores.④The increase of water content will make the Loess particles more dense,and the content of binder phase between particles is also increasing.