School of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, People's Republic of China.
Key Laboratory of Geotechnical and Underground Space Engineering, Shaanxi Province/Xi'an University of Architecture and Technology, Xi'an, 710055, People's Republic of China.
Sci Rep. 2023 Mar 13;13(1):4113. doi: 10.1038/s41598-023-31397-y.
Collapsibility and structural are two of the typical characteristics of natural undisturbed loess. It is of great significance to effectively simulate the collapsibility and structural of natural loess by preparing artificially loess. However, the existing methods of artificially preparing collapsible loess are complex, and the collapsibility of the prepared samples is difficult to control. In this paper, the collapsibility mechanism of loess was re-analyzed, and on this basis, a new method for preparing artificial collapsible loess using remolded loess, industrial salt, CaO particles and gypsum powder was proposed. The basic principle is: the CaO particles have structural strength and would transfer to Ca(OH) after soaking, this progress can simulate the disappearance of loess structural strength; The dissolution of industrial salt can simulate the collapse of loess internal pores, the collapsibility of artificial loess can be adjusted by adjusting the percentage of industrial salt; the gypsum powder can simulate the cementation of loess as a bonding material. The shear test, consolidation test and collapsibility test of artificially prepared loess and undisturbed loess were carried out. The test results of artificial loess were compared with undisturbed loess. The results show that: the plastic limit and liquid limit of the artificially prepared loess is smaller than that of the undisturbed loess; The optimal moisture content and maximum dry density are close to that of the undisturbed loess; The collapsibility coefficient of artificial prepared samples increases first and then decreases with the increase of load level, and gradually increases with the increase of industrial salt particle content; The structural parameters of artificially prepared loess samples first increase and then decrease with the shear process, but the structural parameters of artificial prepared loess and undisturbed loess are different under different confining pressure conditions.
collapsibility 和 structural 是天然原状黄土的两个典型特征。通过人工制备黄土来有效模拟黄土的 collapsibility 和 structural 具有重要意义。然而，现有的人工制备 collapsible 黄土的方法比较复杂，且制备样品的 collapsibility 难以控制。本文重新分析了黄土的 collapsibility 机制，并在此基础上提出了一种使用重塑黄土、工业盐、CaO 颗粒和石膏粉制备人工 collapsible 黄土的新方法。其基本原理是：CaO 颗粒具有结构性强度，浸泡后会转化为 Ca(OH)2，这一过程可以模拟黄土结构性强度的消失；工业盐的溶解可以模拟黄土内部孔隙的 collapse，通过调整工业盐的百分比可以调节人工黄土的 collapsibility；石膏粉可以模拟黄土的胶结作用作为粘结材料。对人工制备的黄土和原状黄土进行了剪切试验、固结试验和 collapsibility 试验。将人工黄土的试验结果与原状黄土进行了比较。结果表明：人工制备的黄土的塑性指数和液性指数小于原状黄土；最优含水量和最大干密度接近原状黄土；人工制备样品的 collapsibility 系数随荷载水平的增加先增大后减小，随工业盐颗粒含量的增加而逐渐增大；人工制备黄土样品的结构参数随剪切过程先增大后减小，但在不同围压条件下，人工制备黄土和原状黄土的结构参数不同。
