西藏嵩草根系抗拉特性试验研究  

Experimental study on the tensile properties of Kobresia tibetica root system

作　　者：张玉 宋路[1] 张珂 刘国松 朱海丽[1,2] ZHANG Yu;SONG Lu;ZHANG Ke;LIU Guosong;ZHU Haili(College of Geological Engineering,Qinghai University,Xining 810016,China;Key Laboratory of Cenozoic Resource&Environment in Northern Margin of Tibetan Plateau,Xining 810016,China)

机构地区：[1]青海大学地质工程系,青海西宁810016 [2]青藏高原北缘新生代资源环境重点实验室,青海西宁810016

出　　处：《青海大学学报》2023年第2期8-15,共8页Journal of Qinghai University

基　　金：青海省科学技术厅项目(2021-ZJ-927);国家自然科学基金项目(42062019,41762023)。

摘　　要：为研究黄河源区曲流河岸优势植物种在单调荷载和循环荷载拉伸下的受力特性,以滨河优势植物种西藏嵩草(Kobresia tibetica)为研究对象,开展不同拉伸标距和不同拉伸速率的轴向单调荷载拉伸试验及不同循环次数条件下的疲劳拉伸试验。结果表明:西藏嵩草根系单根抗拉强度随着拉伸标距和拉伸速率的增大均呈减小的趋势,其减小幅度最大达到31.67%,在5 mm/min拉伸速率下能充分发挥西藏嵩草的抗拉作用。对西藏嵩草根系分别进行50次和100次循环荷载后,单根抗疲劳拉伸强度与根径呈指数函数负相关关系,较单调荷载其单根平均抗拉强度增大幅度为7.21%和17.13%;随着循环次数的增加,西藏嵩草根系拉伸应力—应变曲线滞回环间距越来越密集,最后滞回环几乎在同一个滞回环上不断重复直至断裂或达到循环次数。西藏嵩草根系具有较强的抗疲劳拉伸特性,对减缓河岸崩塌速率有一定作用。In order to investigate the mechanical characteristics of dominant plant species on meandering riverbanks in the source area of the Yellow River under monotonic load and cyclic load tension,Kobresia tibetica,a dominant riverside plant,is taken as the research object to carry out axial monotonic load tension tests with different tensile gauge lengths and tensile rates and fatigue tension tests with different cycles.The results show that the tensile strength of single root of Kobresia tibetica decreases with the increase of tensile gauge length and tensile rate.The maximum reduction is 3167%.The tensile effect of Kobresia tibetica can be fully exerted with the tensile rate of 5 mm/min.After 50 and 100 times of cyclic load,the fatigue tensile strength of single root of Kobresia tibetica shows an exponential negative correlation with its root diameter.The average tensile strength of single root increases by 721%and 1713%compared with monotonic load;the spacing of hysteresis loops in the tensile stress strain curve of its root becomes increasingly dense with the increase of cycles.Finally,the hysteresis loops almost repeat on the same loop until they break or reach the number of cycles.Kobresia tibetica root system has a strong anti fatigue tensile property,which has a certain role in slowing down the rate of bank collapse.

关 键 词：单调荷载 循环荷载 西藏嵩草 拉伸标距 拉伸速率 

分 类 号：TV861[水利工程—水利水电工程] S812[农业科学—草业科学]