Abstract
The soil of the Loess Plateau is highly susceptible to erosion due to its distinct loess structure with poor water stability and disintegrates easily. Previous research has focused on improving soil strength without considering stability and ecological performance. Comprehensive improvements may be achieved by cross-linked polymers (CLPs), but their effect on loess structure remains unclear. In the present study, we investigate CLPs as a new organic soil stabilizer to improve soil aggregate stability. To determine the effect of CLPs on the stabilization of loess, a series of indoor tests was conducted to assess unconfined compressive strength, water stability, soil-water characteristics, and plant height. The stabilization mechanism was analyzed by comparing the microstructure, mineral composition, and features of functional groups of loess before and after treatment. The results showed that, compared with untreated loess, the unconfined compressive strength and anti-disintegration property of treated loess were significantly increased. The water retention capacity was improved, and the germination rate and growth of plants were promoted. Microscopic analysis showed that the use of CLPs did form new minerals in the loess or change the functional groups, rather, CLPs improved the microstructure, reduced the total volume of pores, and increased the degree of soil compaction. Field tests showed that the erosion of loess hillsides was effectively controlled by CLPs. Under the same erosive conditions, the slope surface treated with CLPs was more intact than the untreated slope surface. Our findings provide new strategies regarding the application of CLPs as soil stabilizers to control loess erosion and promote vegetation restoration.
Highlights
Loess is rich in calcium and soluble salts; its structure is loose, cementation is weak, and large pores and vertical joints develop
To explain the stabilization mechanism, the effects of cross-linked polymers (CLPs) on loess particles, pore characteristics, mineral composition, and functional groups were studied through scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fouriertransform infrared spectra (FTIR)
Compared with the untreated samples, the σf of the treated samples notably increased, while Figures 4E,F shows the change trend in the unconfined compressive strength (UCS) of samples treated with different concentrations of CLP with curing time
Summary
Loess is rich in calcium and soluble salts; its structure is loose, cementation is weak, and large pores and vertical joints develop. Plateau, exposed slopes have been produced, causing serious soil erosion (Hu et al, 2020; Wu et al, 2020). The factors influencing soil erosion on loess slopes can be summarized into four categories: rainfall, soil erodibility, topography, and slope surface cover (Liu et al, 2019). Erosion control can be achieved by, for example, planting trees and grass (Chen et al, 2018; Yan et al, 2021) or laying artificial turf (Li et al, 2020). There remain challenges associated with implementing these physical measures, such as large engineering volume, complicated construction, and incomplete erosion control. Such measures mainly strengthen the macroscopic structure of the slope, but they fail to alter the soil properties. For the problem of loess erosion, the microstructure of loess can be fundamentally improved by stabilizers to improve soil stability
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