通过进行室外种植试验和室内根系试验,研究了香根草根系对土壤的增强作用。分析了不同根系含量的土壤标本的开裂指标,并建立了统计模型来确定开裂指标之间的关系,干循环和湿循环的次数,和根内容。研究揭示了香根草加筋膨胀土的裂缝演化规律。研究探索了植被根系抑制膨胀土开裂的机理,并通过室外种植试验确定了香根草的最佳种植密度。结果表明:表面裂纹率(CR),总裂纹长度(CL),根土样品中的裂缝数(CN)随着干湿循环次数的增加而呈指数增长。这种增长在第一和第二周期期间更为明显。香根草根可以有效减少土壤裂缝的形成,样品的抗开裂性与根系含量呈正相关。随着根系含量的增加,CR,CN,CL下降。Logistic模型适用于添加根土的CL。logistic模型更适用于根系含量较低的膨胀土CR的生长模型,Boltzmann模型更适用于根系含量较高的膨胀土CR的生长模型。裂纹宽度(CW)更适合DoseResp生长模型。玻尔兹曼模型更适用于低加筋膨胀土中的CN,而logistic生长模型更适合于根系含量在0.21%以上的CN的发育。裂缝网络的发展受两个关键因素的影响:根部含量和干湿循环次数。在植根的条件下,膨胀土中裂缝网络的发育与添加根的膨胀土不同,没有明确的模式可以遵循。香根草根对膨胀土开裂的抑制作用与香根草的种植密度有关。
The study investigated the reinforcing effect of vetiver root on soil by conducting outdoor planting tests and indoor root tests. The
cracking indexes of soil specimens with varying root contents were analyzed, and a statistical model was established to determine the relationship between the
cracking indexes, the number of dry and wet cycles, and the root content. The study revealed the crack evolution law of vetiver-reinforced expansive soil. The study explored the mechanism of the vegetation root in inhibiting the
cracking of expansive soil and determined the optimal planting density of vetiver grass through outdoor planting tests. The results indicate that: The surface crack rate (CR), total crack length (CL), and crack number (CN) in the root-soil specimen exhibited exponential growth with an increase in the number of wet and dry cycles. This growth was more pronounced during the first and second cycles. The vetiver root could effectively reduce soil crack formation, and the specimen\'s
cracking resistance is positively correlated with the root content. With the root content increased, the CR, CN, and CL decreased. The logistic model is suited to the CL of added root soil. The logistic model is more suitable for the growth model of the CR of the expansive soil with low root content, while the Boltzmann model is more suitable for the growth model of the CR of the expansive soil with high root content. Width of crack (CW) is better suited to the DoseResp growth model. The Boltzmann model is more applicable to the CN in expansive soils with low reinforcement, while the logistic growth model is more suitable for the development of CN above 0.21% root content. The development of the crack network was influenced by two key factors: the root content and the number of wet and dry cycles. Under the condition of planting roots, the development of crack networks in expansive soil differs from that of expansive soil with added roots, and there is no clear pattern to follow. The inhibitory effect of the vetiver root on
cracking of expansive soil is related to the planting density of vetiver.