基于植物柔韧性的土壤生物工程护岸材料选择

Plant material selection for riverbank protection by using soil bioengineering based on plant flexibility

以北京市怀柔区怀九河为例,运用三点抗弯的方法,对金丝柳、旱柳、紫穗槐和荆条4种植物进行枝条抗弯实验,通过对植物枝条柔韧性的研究,筛选出适用于退化河岸带土壤生物工程生态修复的植物材料。结果表明:将植物的力学特性分析作为河岸带土壤生物工程植物材料的选择依据是一种可行的方法;弹性模量小、抗弯力大的植物是土壤生物工程施工中优先选择的植物材料。研究表明:抗弯力强度与植物直径呈显著正相关关系;荆条弹性模量最大且远高于其他3种植物,其次为紫穗槐;旱柳和金丝柳弹性模量差异不大;荆条的抗弯力最大,旱柳最小。因此从力学角度出发,在土壤生物工程植物材料筛选中,乔木树种优先选择金丝柳,其次为旱柳;灌木树种优选紫穗槐,荆条次之。

Taking Huaijiu River in Huairou District of Beijing as an example, four species of plant materials including Salix aureo-pendula, S. matsudana, Amorpha fruticosa and Vitex negundo var. heterophylla were chosen to take the three point toughness test for the purpose of analysing the flexibility of plant materials, and selecting proper species for degraded riverbank ecological restoration construction. The results showed that the choice of materials for soil bioengineering project based on mechanical analysis of plant was probably a feasible method. Riverbank restoration should give preference to plants with small elastic modulus and big anti-bending force. By analysing the experiment data, we found that anti-bending force was significantly positive with plant diameter; V. negundo var. heterophylla was the plant species which had the biggest elastic modulus compared with others, A. fruticosa was the second. While for S. aureo-pendula and S. matsudana, there was little difference. In respect of anti-bending force, V. negundo var. heterophylla was the biggest while S. matsudana was the smallest. Therefore as a point of view, S. aureo-pendula is superior to S. matsudana as arbor species, and for frutex, A. fruticosa is better than V. negundo var. heterophylla.