两种草本植物对红黏土边坡的固土护坡效应

Soil Strengthening and Slope Protection Effect of Two Types of Herbaceous Plants on Red Clay Slopes

[目的]探讨两种草本植物对红黏土边坡的固土护坡效应,为该类型边坡、河道、大坝的生态治理提供科学参考。[方法]以红黏土边坡为研究对象,选取狗牙根和香根草作为护坡植物,通过种植试验、根系拉伸试验、直剪试验、室内模拟冲刷试验,探讨两种草本植物的护坡效应。[结果]①种植150 d内,两种草本植物均稳定生长,根系抗拉强度持续增加;生长30~150 d,狗牙根的最大抗拉力从0.84 N增至8.59 N,香根草的最大抗拉力从4.78 N增至89.89 N。②生长120 d时,对比无根土,狗牙根根土复合体的黏聚力提升91.1%,内摩擦角提升12.45%;香根草根土复合体的黏聚力提升107.47%,内摩擦角提升12.74%。③生长150 d时,对比裸坡,狗牙根坡的径流速率降低45.02%~54.15%,产沙速率降低58.3%~93.85%,60 min累计产沙量降低81.02%;香根草坡的径流速率降低35.46%~46.48%,产沙速率降低46.8%~89.44%,60 min累计产沙量降低74.61%。[结论]两种草本植物对红黏土边坡都具有良好的固土护坡效应,香根草对土体抗剪强度的增益效果更明显,狗牙根的水土保持效果更显著。

[Objective]Soil strengthening and slope protection effects of two kinds of herbaceous plants were explored on red clay slope in order to provide scientific references for the ecological management of this type of slope,river channel,and dam.[Methods]With red clay slope as the research object,Cynodon dactylon and vetiver grass were selected as slope protection plants.The slope protection effect of the two herbaceous plants was determined through planting tests,root tensile tests,direct shear tests,and indoor simulated scouring tests.[Results]①Within 150 days of planting,both herbaceous plants grew steadily and the tensile strength of the root system continued to increase.From 30 to 150 days of growth,the maximum tensile strength of Cynodon dactylon roots increased from 0.84 N to 8.59 N,and that of vetiver grass increased from 4.78 N to 89.89 N.②At 120 days of growth,the cohesion of the Cynodon dactylon root-soil complex was 91.1%greater than the cohesion of rootless soil,and the angle of internal friction increased by 12.45%.The cohesion of the vetiver grass root-soil complex was 107.47%greater than that of rootless soil,and the angle of internal friction increased by 12.74%.③The runoff rate of the Cynodon dactylon slope at 150 days of growth was 45.02%to 54.15%less than observed on a bare slope,while the sediment yield rate was 58.3%to 93.85%less,and the 60 min cumulative sediment yield was 81.02%less.Similarly,the runoff rate of the vetiver grass slope was 35.46%to 46.48%less than observed on a bare slope,while the sediment yield was 46.8%to 89.44%less,and the 60 min have sediment yield was 74.61%less.[Conclusion]Both herbaceous plants had excellent soil consolidation and slope protection effects on red clay slopes,with vetiver grass having a more pronounced effect on the increase in soil shear strength,and Cynodon dactylon having a more significant effect on soil and water conservation.