陕北黄土区不同植物根系抗拉力学特性研究

目的]单根抗拉力学特性是植物发挥固土护坡作用的重要因素，乡土植物分布广泛对区域固土护坡起主要作用，研究比较不同植物单根抗拉力学特性，对坡陡沟深、滑塌频发的黄土区护坡植物选择具有重要意义。方法]以陕北黄土区的截叶铁扫帚、猪毛蒿、大针茅、铁杆蒿、茭蒿和细叶薹草6种常见乡土植物为研究对象，通过室内单根拉伸试验，比较分析了以上6种植物不同根径单根抗拉力、单根抗拉强度和单根延伸率等力学特性。结果](1)在根径范围内，6种植物单根抗拉力与根径呈幂函数形(y=ax^b,b>0)正相关关系，植物单根抗拉强度与根径呈幂函数形(y=ax^b,b<0)负相关关系；6种植物单根延伸率随着根径的增加呈现出增大趋势，但单根延伸率与根径之间未呈现出显著的相关性。(2)在试验根径0.05～0.60 mm范围内，植物种类对单根抗拉力、单根抗拉强度和单根延伸率的影响都达到显著水平，6种植物平均单根抗拉力关系为：细叶薹草(10.20 N)>大针茅(7.39 N)>铁杆蒿(6.87 N)>茭蒿(6.44 N)>猪毛蒿(6.34 N)>截叶...

Study on Root Tensile Mechanical Properties of Six Typical Plants in the Loess Area of Northern Shaanxi

Objective] The tensile mechanical properties of a single root are the important factors for plants to play the role in soil consolidating and slope protection, the wide distribution of native plants plays a major role in regional soil consolidating and slope protection. It is of great significance to study and compare the tensile mechanical properties of different plant root systems for the selection of slope protection plants in loess areas with steep slopes, deep grooves and frequent landslides. Methods] The six native plants(Lespedeza cuneata, Artemisia scoparia, Stipa grandis, Artemisia sacrorum, Artemisia giraldii and Carex duriuscula subsp. stenophylloides)in the loess region of northern Shaanxi were selected as the study samples. Through indoor single root tensile test, the mechanical properties of single root tensile force, single root tensile strength and single root extensile rate of the above six plants with different root diameters were compared and analyzed. Results](1)Within the root diameter range, with the increase of root diameter, the single root tensile forces and single root tensile strengths of 6 plant species followed the increase pattern of a power function e(y=ax^b,b>0)and the decrease pattern of a power function, respectively(y=ax^b,b<0); moreover, the single root limit extensile rates of the 6 plant species increased with the increasing of the root diameter, but there was no significant correlation relationship between them.(2)In the range of 0.05～0.60 mm of root diameter, the influences of plant species on single root tensile force, single root tensile strength and single root extensile rate reached the significant level, and the average tensile forces of the six species decreased in the order: Carex duriuscula subsp. Stenophylloides (10.20 N)>Stipa grandis (7.39 N)>Artemisia sacrorum (6.87 N)>Artemisia giraldii (6.44 N)>Artemisia scoparia (6.34 N)>Lespedeza cuneata (3.37 N); the average tensile strength ranked as Artemisia giraldii (148.44 MPa)>Artemisia sacrorum (141.96 MPa)>Stipa grandis (132.95 MPa)>Carex duriuscula subsp. Stenophylloides (132.68 MPa)>Artemisia scoparia (115.07 MPa)>Lespedeza cuneata (85.86 MPa); the single root extensile rate was in order as Carex duriuscula subsp. Stenophylloides (32.37%)>Artemisia scoparia (17.01%)>Stipa grandis (13.60%)>Artemisia sacrorum (13.15%)>Artemisia giraldii(13.09%)>Lespedeza cuneata (6.98%). Conclusion] The tensile mechanical properties of the single root of Carex duriuscula subsp. Stenophylloides are better than those of other plants. The results of this study can provide a certain scientific basis for the study of soil and water conservation in the loess area of northern Shaanxi.