IMHE OpenIR  > 山地灾害与地表过程重点实验室
泥石流活动区典型乔灌植物根系组合固土效应研究
Alternative TitleStudy on combined solid soil effect of typical tree and shrub in debris flow area
方迎潮
Subtype硕士
Thesis Advisor王道杰
2018
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline建筑与土木工程
Keyword泥石流 组合根系 固土 抗剪强度
Abstract泥石流活动区水土流失严重,灾害频繁,植被的恢复能够有效固土护坡,抑制泥石流灾害的发生。本文以西南山区典型暴雨泥石流沟-云南东川蒋家沟作为研究地,选取具有代表性的乔灌植物新银合欢、马桑,进行乔灌组合固土效应研究,为泥石流活动区减少水土流失进而减弱山地灾害的发生提供一定的理论依据。本文通过对云南东川蒋家沟流域内新银合欢、马桑植被调查,根系挖掘,研究流域内两种典型植物的分布情况,根系的形态及空间分布范围,采用根的抗拉试验确定新银合欢、马桑根二者的抗拉强度指标,最后通过三轴试验和直剪试验,分析乔灌植物不同组合根系土体抗剪强度及相应的指标。(1)调查结果显示,新银合欢主要分布在蒋家沟流域的大凹子沟下游、中国科学院东川泥石流观测站附近、老蒋家沟及下游排导槽两侧,其中蒋家沟观测站附近以成龄林为主,而其他则为幼龄林;马桑分布范围广但较稀疏,从门前沟和多照沟上游各支沟至泥石流观测站皆有分布,但主要集中分布于阳坡一侧。(2)根系挖掘发现,新银合欢属于垂直型根系,主根深且直,侧向分布范围小,有利于深层锚固,马桑为横走型根系,水平根和斜出根发达,根系垂向分布较浅,但侧向分布很广,有利于浅层的加筋,两者的组合能够更好的发挥根系固土的作用。不管是新银合欢还是马桑,细根在空间上的分布较为广泛,粗根则比较集中。(3)植物根的抗拉试验结果表明,新银合欢和马桑根的抗拉力与直径呈幂函数的关系,分别为y=10.44x1.744(R2=0.69)、y=10.2x1.575(R2=0.72);根的应力应变曲线表明,新银合欢根的断裂方式为塑性断裂,马桑根的断裂方式为脆性断裂。(4)直径1mm、2mm水平组合根能够有效增强土体抗剪强度,垂直组合根在围压50kPa、100kPa下能有效增强土体抗剪强度,200kPa时2mm垂直组合根降低土体抗剪强度。(5)主应力差增幅随水平组合根层数、根数的增加而增大,直径1mm组合根与直径2mm组合根在6根时趋于一致,说明水平组合根数对土体强度的影响存在一个上限;围压50kPa、100kPa时2mm水平组合根更有利于土体抗剪强度的增强;围压200kPa时1mm水平组合根对土体抗剪强度的增强较明显。(6)直径1mm、2mm水平组合根增加土体的粘聚力,而对土体内摩擦角影响很小;1mm、2mm垂直组合根既能影响粘聚力也能影响内摩擦角,但对粘聚力的影响要大于对内摩擦角的影响。(7)直径3mm、5mm组合根的存在也能有效的增强土体的抗剪强度值,其中直径5mm组合根的效果强于直径3mm组合根系,且最佳根土面积比受直径和垂直压力的共同影响。(8)直径3mm、5mm组合根既影响粘聚力也影响内摩擦角,3mm与5mm组合根粘聚力与根系数量的拟合函数分别为y=-0.65x2+4.24x+20.58(R2=0.95)、y=-0.81x2+5.1x+20.59(R2=0.96);内摩擦角与根系数量拟合函数分别为y=0.16x2-0.64x+29.53(R2=0.87)、y=0.16x2-0.56x+29.49(R2=0.86)。
Other AbstractSoil and water loss is serious and frequent in debris flow area, but the restoration of vegetation can effectively reinforce soil and protect slope, which In turn can suppress the occurrence of debris flow. The study area is Jiangjia gully, Dongchuan district, Yunnan province, which is famous for debris flow by heavy rains. Leucaena and coriaria is choose the typical plant to study their combined solid soil effect, in order to provide theoretical basis for reducing soil erosion and preventing geological disasters.Understand the distribution by Investigating the Leucaena and coriaria vegetation in jiangjiagou gully. Digging roots is used to study the root morphology and spatial distribution. The tensile strength index of root is determined by root tensile test. At last, through triaxial test and direct shear test, the shear strength and the corresponding indexes of different combinations of the root soil were analyzed.(1) Results show that Leucaena mainly distribute in the downstream of Dawazi gully, debris flow observatory, Jiangjia old gully and both sides of platoon guide. Among them, the observation station is dominated by adult forest, while others are young forest. The distribution of coriaria is wide but sparse, which mainly concentrate on the side of slope from the upstream of Menqian and Duozhao gully to the observation station.(2) Root mining discovery that the root type of Leucaena is Vertical type, the main root is deep and straight and the lateral distribution is small, which is good for deep anchorage. Coriaria is parallel and horizontal, horizontal roots and diagonal roots are numerous, but the lateral distribution is very wide, which is beneficial to the shallow reinforcement. The combination of the two can better play the role of rooting soil. Whether it is Leucaena or Coriaria, the fine roots are more widely distributed in space, and the coarse roots are more concentrated. (3) The tensile test results of plant roots show that that the tension and diameter of the Leucaena and the Coriaria roots are power function, respectively y=10.44x1.744(R2=0.69)、y=10.2x1.575(R2=0.72). The stress and strain curve shows that the fracture mode of the Leucaena root system is plastic fracture, and the fracture mode of the Coriaria root system is brittle fracture.(4) The diameter of 1 mm, 2 mm level combination of root system can effectively enhance the soil shear strength, vertical combination of root under confining pressure 50 kpa, 100 kpa can effectively enhance the soil shear strength, while 200 kpa vertical combination of fine root 2 mm diameter lower shear strength of soil.(5) The principal stress difference increases with the level of combination of root layer increases with increasing of the number, root number, 1 mm diameter combination of root and the roots of 2 mm diameter combination in 6, shows the number of levels influence on soil strength there is a limit; The combined root system of 50kPa and 100kPa was more conducive to the strengthening of soil shear strength. The strength of soil shear strength was enhanced by 1mm combined root system at 200kPa.(6) The horizontal combination of 1mm and 2mm diameter increases the cohesion of the soil, while the effect on the internal friction Angle of the soil is very small. The vertical combination of 1mm and 2mm can affect both cohesion and internal friction Angle, but the effect of cohesion is greater than that of internal friction Angle.(7) The presence of coarse roots in soil also can effectively enhance the shear strength value of the combination of root 5 mm diameter is stronger than the effect of combination of root 3 mm diameter, and the best area ratio of root to affected by the diameter and vertical pressure together.(8) The root system with diameter of 3mm and 5mm affects both cohesion and internal friction Angle. The fitting function of the root cohesion and the number of root systems of 3mm and 5mm are y=-0.65x2+4.24x+20.58(R2=0.95)、y=-0.81x2+5.1x+20.59(R2=0.96). The fitting function of internal friction Angle and root number is y=0.16x2-0.64x+29.53(R2=0.87)、y=0.16x2-0.56x+29.49(R2=0.86). 
Pages106
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24783
Collection山地灾害与地表过程重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
First Author Affilication中国科学院水利部成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
方迎潮. 泥石流活动区典型乔灌植物根系组合固土效应研究[D]. 北京. 中国科学院大学,2018.
Files in This Item:
File Name/Size DocType Version Access License
泥石流活动区典型乔灌植物根系组合固土效应(4905KB)学位论文 开放获取CC BY-NC-SAView Application Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[方迎潮]'s Articles
Baidu academic
Similar articles in Baidu academic
[方迎潮]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[方迎潮]'s Articles
Terms of Use
No data!
Social Bookmark/Share
File name: 泥石流活动区典型乔灌植物根系组合固土效应研究.pdf
Format: Adobe PDF
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.