School of Civil Engineering and Architecture, Guangxi University, Nanning, 530004, China.
Key Laboratory of Disaster Prevention and Structural Safety, Guangxi University, Nanning, 530004, China.
Sci Rep. 2023 Aug 11;13(1):13052. doi: 10.1038/s41598-023-39770-7.
Expansive soil exhibits remarkable characteristics of water absorption expansion and water loss shrinkage, rendering it susceptible to cracking under the alternating dry-wet environments of nature. The generation and development of cracks in expansive soil can result in catastrophic engineering accidents such as landslides. Vegetation protection is an important approach to stabilizing expansive soil slopes and fulfilling ecological protection requirements. In this study, through indoor experiments and theoretical analysis methods, the effects of Cynodon dactylon roots on the crack development and shear strength of expansive soil subjected to dry-wet cycles were analyzed, and the relationship between the crack development and shear strength decay in root-doped expansive soil was explored. Furthermore, the mechanism of vegetative root system action was elucidated. The results show that the Cynodon dactylon root system exerts a significant inhibitory effect on crack development in expansive soil. The crack indexes of root-doped expansive soil exhibit significant phase characteristics during the process of dry-wet cycles. The crack-blocking and reinforcing effect of the root system becomes pronounced as the root-to-soil mass ratio increases and the root diameter decreased. Moreover, the process of crack development in expansive soil is accompanied by a decrease in soil shear strength. The quantitative relationship between crack development and shear strength decay can serve as a basis for predicting the stability of slope soil. Overall, the results highlight the potential of vegetation-based approaches in protecting slopes with expansive soils and have practical implications for ecological protection and engineering design in areas with expansive soils.
膨胀土具有显著的吸水膨胀、失水收缩特性，在自然干湿环境的交替作用下易产生开裂。膨胀土中裂缝的产生和发展会导致滑坡等灾难性工程事故。植被防护是稳定膨胀土边坡和满足生态保护要求的重要方法。本研究通过室内试验和理论分析方法，分析了狗牙根根系对干湿循环作用下膨胀土裂缝发展和剪切强度的影响，探讨了掺根膨胀土裂缝发展与剪切强度衰减的关系，并阐明了植被根系作用的机理。结果表明，狗牙根根系对膨胀土裂缝的发展具有显著的抑制作用。在干湿循环过程中，掺根膨胀土的裂缝指标表现出明显的阶段特征。随着根土质量比的增加和根径的减小，根系的阻裂和增强作用变得明显。此外，膨胀土中裂缝的发展伴随着土壤抗剪强度的降低。裂缝发展与剪切强度衰减的定量关系可作为预测边坡土稳定性的依据。总的来说，研究结果强调了基于植被的方法在保护膨胀土边坡方面的潜力，对膨胀土地区的生态保护和工程设计具有实际意义。
