Zhan Peng,Zhang Chaobo,Zhang Qiang,et al.Effects of Alfalfa Roots on the Shear Properties of Loess Under Alternate Drying-Wetting Conditions[J].Research of Soil and Water Conservation,2023,30(06):222-230.[doi:10.13869/j.cnki.rswc.2023.06.006]
干湿交替下苜蓿根系对黄土抗剪力学性能影响
- Title:
- Effects of Alfalfa Roots on the Shear Properties of Loess Under Alternate Drying-Wetting Conditions
- 文章编号:
- 1005-3409(2023)06-0222-09
- 分类号:
- S157.2
- 文献标志码:
- A
- 摘要:
- [目的]探究干湿交替下植物根系对黄土抗剪性能的影响,为常年处于干湿交替状态下的黄土区生态建设和工程建设提供理论基础。[方法]以黄土区典型草本植物苜蓿为研究对象,采用室内直剪试验,研究黄土抗剪特性与干湿交替作用、根系尺寸(根长、根径)、土体容重、含水率等影响因素的关系,并基于Wu模型评估了根系对土体抗剪特性的增强作用。[结果]经历干湿交替后的根土复合体表面变得粗糙、松散、易脱落,并出现不均匀裂隙,而且其抗剪性能指标均呈降低趋势。干湿交替下,根系尺寸显著影响根土复合体抗剪特性,根长越长,根径越大,其抗剪强度越大。在一定范围内,黏聚力、内摩擦角与土体容重呈正相关关系。不同容重的根土复合体,经历干湿交替作用后,其黏聚力、内摩擦角均降低。相同干湿交替作用下,黏聚力随着含水率的增加呈先增加再降低的趋势; 相同含水率水平下,进行干湿交替土体抗剪强度指标均弱于原状土体。Wu模型的局限性导致模型估算根系附加黏聚力结果与实际值相差较大,可以采用根系抗拔强度替换根系抗拉强度,优化Wu模型对根系附加黏聚力的估算结果。[结论]干湿交替下,植物根系尺寸、土壤容重与土壤含水率都对黄土抗剪性能有一定影响。
- Abstract:
- [Objective] The aim of this study is to explore the influence of plant roots on shear properties of loess under alternate drying-wetting conditions and provide a theoretical basis for the ecological construction and engineering construction in the loess region under the state of alternate drying-wetting. [Methods] Direct shear test in laboratory was conducted on loess samples with/without alfalfa roots to study the relationship between shear properties of loess and influencing factors including alternate drying-wetting, root size(root length, root diameter), soil bulk density and water content, and to evaluate the reinforcement of roots on shear resistance of loess based on the Wu model. [Results] The surface of root-soil composite became rough, loose and easy to fall off after alternate drying-wetting, and uneven cracks appeared. The shear indexes of the composite decreased after alternate drying-wetting. Root size significantly affected the shear behavior of root-soil composite under alternate drying-wetting conditions. Longer and larger roots resulted in greater soil shear strength. Soil cohesion and internal friction angle were positively correlated with soil bulk density in a certain range, and they decreased after alternate drying-wetting. Under the same alternate drying-wetting condition, the cohesion first increased and then decreased with soil water content. At the same level of soil water content, shear strength was weaker in soil under alternate drying-wetting than in soil without alternate drying-wetting. The limitations of the Wu model led to the relatively wide difference between the results by the model and the values by the shear tests. The estimation results of root cohesion by Wu model could be optimized by replacing root tensile strength with root pullout strength. [Conclusion] Under alternate drying-wetting conditions, the size of plant roots, soil bulk density, and soil moisture content all have a certain impact on the shear resistance of loess.
参考文献/References:
[1] 程士源.山西黄土地区地质灾害与工程活动特殊性的研究[D].太原:太原理工大学,2017.
Cheng S Y. Research on the Geological Hazards and the Particularity of Engineering Activities in the Loess Area of Shanxi[D]. Taiyuan: Taiyuan University of Technology, 2017.
[2] 李宗善,杨磊,王国梁,等.黄土高原水土流失治理现状、问题及对策[J].生态学报,2019,39(20):7398-7409.
Li Z S, Yang L, Wang G L, et al. The management of soil and water conservation in the Loess Plateau of China: Present situations, problems, and counter-solutions[J]. Acta Ecologica Sinica, 2019,39(20):7398-7409.
[3] 徐华,袁海莉,王歆宇,等.根系形态和层次结构对根土复合体力学特性影响研究[J].岩土工程学报,2022,44(5):926-935.
Xu H, Yuan H L, Wang X Y, et al. Influences of morphology and hierarchy of roots on mechanical characteristics of root-soil composites[J]. Chinese Journal of Geotechnical Engineering, 2022,44(5):926-935.
[4] 邢书昆,张光辉,朱平宗.黄土丘陵沟壑区退耕年限对根-土复合体抗剪强度的影响[J].水土保持学报,2021,35(4):41-48,54.
Xing S K, Zhang G H, Zhu P Z, et al. Effects of vegetation restoration age on shear strength of root-soil system in hilly and gully region of Loess Plateau[J]. Journal of Soil and Water Conservation, 2021,35(4):41-48,54.
[5] 刘亚斌,胡夏嵩,余冬梅,等.西宁盆地黄土区草本和灌木组合根系分布特征及其增强土体抗剪强度效应[J].工程地质学报,2020,28(3):471-481.
Liu Y B, Hu X S, Yu D M, et al. Distribution characteristics of combined herb and shrub roots in loess area of Xining basin and their effect on enhancing soil shear strength[J]. Journal of Engineering Geology, 2020,28(3):471-481.
[6] Gray D H. Biotechnical and soil bioengineering slope stabilization: A practical guide for erosion control[J]. Soil Science, 1998,163(1):83-85.
[7] 董超凡,张吾渝,孙翔龙,等.木质素纤维改良黄土抗剪强度的试验研究[J].安全与环境工程,2022,29(2):102-110.
Dong C F, Zhang W Y, Sun X L, et al. Experimental study on the shear strength of lignin fiber-improved loess[J]. Safety and Environmental Engineering, 2022,29(2):102-110.
[8] 孙召军,李金山,贾艳辉,等.干湿交替次数对土壤干密度和饱和导水率的影响[J].灌溉排水学报,2022,41(6):89-96.
Sun Z J, Li J S, Jia Y H, et al. Effects of wetting-drying cycles on bulk density and saturated hydraulic conductivity of soils[J]. Journal of Irrigation and Drainage, 2022,41(6):89-96.
[9] 尹宏磊,徐千军,李仲奎.抗剪强度随干湿循环变化对边坡安定性的影响[J].水利学报,2008,39(5):568-572,579.
Yin H L, Xu Q J, Li Z K. Analysis on spatial and temporal variability of groundwater level based on spherical sampling model[J]. Journal of Hydraulic Engineering, 2008,39(5):568-572,579.
[10] 汪时机,杨振北,李贤,等.干湿交替下膨胀土裂隙演化与强度衰减规律试验研究[J].农业工程学报,2021,37(5):113-122.
Wang S J, Yang Z B, Li X, et al. Experimental study on crack evolution and strength attenuation of expansive soil under wetting-drying cycles[J]. Transactions of the Chinese Society of Agricultural Engineering, 2021,37(5):113-122.
[11] 宋鹏帅,王健,陈琳,等.模拟干湿交替对夯实土壤抗剪强度的影响[J].水土保持研究,2021,28(2):74-79.
Song P S, Wang J, Chen L, et al. Effect of wet-dry cycle on shear strength of compacted soil[J]. Research of Soil and Water Conservation, 2021,28(2):74-79.
[12] Mao Y C, Li G Y, Lei J X, et al. Experimental study on the effects of wetting-drying cycles of compacted loess[J]. Advanced Materials Research, 2014,831:326-330.
[13] 付理想,梅岭.干湿循环对原状及重塑黄土渗透系数的影响分析[J].洛阳理工学院学报:自然科学版,2018,28(1):1-6.
Fu L X, Mei L. Influence analysis of drying and wetting cycles on permeability coefficient of intact and remolded loess[J]. Journal of Luoyang Institute of Science and Technology: Natural Science Edition,2018,28(1):1-6.
[14] 刘宏泰,张爱军,段涛,等.干湿循环对重塑黄土强度和渗透性的影响[J].水利水运工程学报,2010,126(4):38-42.
Liu H T, Zhang A J, Duan T, et al. The influence of alternate dry-wet on the strength and permeability of remolded loess[J]. Hydro-Science and Engineering, 2010,126(4):38-42.
[15] Wu T H, McKinnellⅢ W P, Swanston D N. Strength of tree roots and landslides on Prince of Wales Island, Alaska[J]. Canadian Geotechnical Journal, 1979,16(1):19-33.
[16] Pollen N, Simon A. Estimating the mechanical effects of riparian vegetation on stream bank stability using a fiber bundle model[J]. Water Resources Research, 2005,41(7):226-244.
[17] Schwarz M, Cohen D, Or D. Pullout tests of root analogs and natural root bundles in soil: Experiments and modeling[J]. Journal of Geophysical Research: Earth Surface, 2011,116:F02007.
[18] Fan C C. A displacement-based model for estimating the shear resistance of root-permeated soils[J]. Plant and Soil, 2012,355(1):103-119.
[19] 夏鑫,姜元俊,苏立君,等.基于界面黏结的含根土抗剪强度极限值估算模型[J].岩土力学,2021,42(8):2173-2184.
Xia X, Jiang Y J, Su L J, et al. Estimation model of limit values of shear strength of root-bearing soil based on interface bonding[J]. Rock and Soil Mechanics, 2021,42(8):2173-2184.
[20] 文伟,李光范,胡伟,等.草本植物根系对土体的加筋作用模型修正[J].岩石力学与工程学报,2016,35(S2):4211-4217.
Wen W, Li G F, Hu W, et al. Modification of reinforcement effect model of herbs root system in soil[J]. Chinese Journal of Rock Mechanics and Engineering, 2016,35(S2):4211-4217.
[21] Docker B B, Hubble T. Quantifying root-reinforcement of river bank soils by four Australian tree species[J]. Geomorphology, 2008,100(3/4):401-418.
[22] Waldron L J, Dakessian S. Effect of grass, legume, and tree roots on soil shearing resistance[J]. Soil Science Society of America Journal, 1982,46(5):894-899.
[23] 余冬梅,祁兆鑫,刘亚斌,等.青海柴达木盆地盐湖区5种盐生植物根-土复合体抗剪强度影响因素及评价[J].水土保持研究,2019,26(4):157-165.
Yu D M, Qi Z X, Liu Y B, et al. Factors affecting shear and contribution evaluation of root-soil composite systems of five halophytes in the salt lake region of northwest Qaidam Basin, Qinghai Province[J]. Research of Soil and Water Conservation, 2019,26(4):157-165.
[24] 杨路,杜峰,秦晶晶,等.黄土区3种优势灌木根土复合体的抗剪强度研究[J].水土保持研究,2022,29(1):295-300,310.
Yang L, Du F, Qin J J, et al. Research on shear strength of root-soil complexes of three dominant shrubs in loess region[J]. Research of Soil and Water Conservation, 2022,29(1):295-300,310.
[25] 朱海丽,胡夏嵩,毛小青,等.青藏高原黄土区护坡灌木植物根系力学特性研究[J].岩石力学与工程学报,2008,207(S2):3445-3452.
Zhu H L, Hu X S, Mao X Q, et al. Study on mechanical characteristics of shrub roots for slope protection in loess area of Tibetan plateau[J]. Chinese Journal of Rock Mechanics and Engineering, 2008,207(S2):3445-3452.
[26] 曾召田,吕海波,赵艳林,等.膨胀土干湿循环效应及其对边坡稳定性的影响[J].工程地质学报,2012,20(6):934-939.
Zeng Z T, Lv H B, Zhao Y L, et al. Wetting-drying effect of expansive soils and its influence on slope stability[J]. Journal of Engineering Geology, 2012,20(6):934-939.
[27] 周霞,魏杨,李东嵘,等.黄土区紫花苜蓿根系对土体抗剪性能的影响[J].中国水土保持科学,2019,17(2):53-59.
Zhou X, Wei Y, Li D R, et al. Strengthening effects of alfalfa roots on soil shear resistance in loess region[J]. Science of Soil and Water Conservation, 2019,17(2):53-59.
[28] 朱锦奇,王云琦,王玉杰,等.基于植物生长过程的根系固土机制及Wu模型参数优化[J].林业科学,2018,54(4):49-57.
Zhu J Q, Wang Y Q, Wang Y J, et al. Analyses on root reinforcement mechanism based on plant growth process and parameters optimization of Wu model[J]. Scientia Silvae Sinicae, 2018,54(4):49-57.
[29] 陈安强,张丹,熊东红,等.元谋干热河谷坡面表层土壤力学特性对其抗冲性的影响[J].农业工程学报,2012,28(5):108-113.
Chen A Q, Zhang D, Xiong D H, et al. Effects of mechanical properties of surface soil on soil anti-scourability in Yuanmou dry-hot valley[J]. Transactions of the Chinese Society of Agricultural Engineering, 2012,28(5):108-113.
[30] 赵玉娇,胡夏嵩,李华坦,等.寒旱环境灌木根系增强边坡土体抗剪强度特征[J].农业工程学报,2016,32(11):174-180.
Zhao Y J, Hu X S, Li H T, et al. Characteristics of slope soil shear strength reinforced by shrub roots in cold and arid environments[J]. Transactions of the Chinese Society of Agricultural Engineering, 2016,32(11):174-180.
[31] 甘凤玲,韦杰,李沙沙.紫色土埂坎典型草本根系摩阻特性对土壤含水率的响应[J].草业学报,2022,31(7):28-37.
Gan F L, Wei J, Li S S. Response of root-soil friction characteristics of three common grasses to soil water content in purple soil bunds[J]. Acta Prataculturae Sinica, 2022,31(7):28-37.
相似文献/References:
[1]宋鹏帅,王 健,陈 琳,等.模拟干湿交替对夯实土壤抗剪强度的影响[J].水土保持研究,2021,28(02):74.
SONG Pengshuai,WANG Jian,CHEN Lin,et al.Effect of Wet-Dry Cycle on Shear Strength of Compacted Soil[J].Research of Soil and Water Conservation,2021,28(06):74.
[2]杨 路,杜 峰,秦晶晶,等.黄土区3种优势灌木根土复合体的抗剪强度研究[J].水土保持研究,2022,29(01):295.
YANG Lu,DU Feng,QIN Jingjing,et al.Research on Shear Strengths of Root-Soil Complexes of Three Dominant Shrubs in Loess Region[J].Research of Soil and Water Conservation,2022,29(06):295.
[3]黄梦琦,张超波,丁 阳,等.干湿交替下黄土区苜蓿根系抗拔力学性能[J].水土保持研究,2024,31(01):214.[doi:10.13869/j.cnki.rswc.2024.01.019]
Huang Mengqi,Zhang Chaobo,Ding Yang,et al.Pullout Mechanical Properties of Alfalfa Roots in Loess Region Under Alternate Drying-Wetting[J].Research of Soil and Water Conservation,2024,31(06):214.[doi:10.13869/j.cnki.rswc.2024.01.019]
备注/Memo
收稿日期:2022-08-25 修回日期:2022-09-19
资助项目:山西省基础研究计划项目(20210302123105); 山西省回国留学人员科研资助项目(2020-054)
第一作者:展鹏(1999—),男,甘肃张掖人,硕士研究生,研究方向为生态水利工程。E-mail:1906529398@qq.com
通信作者:张超波(1984—),男,湖南益阳人,博士,副教授,主要从事流域生态修复和边坡保护工程研究。E-mail:zhangchaobo@tyut.edu.cn