为研究植物根系对根土复合体力学特性的影响,开展不同根系含量下的根土复合体三轴试验,分析了根土复合体依赖根系变化的力学特性,建立了根土复合体非线性破坏准则。研究结果表明:根系通过提供抗拉能力来提高土体抗剪强度,根主要影响土体黏聚力,对内摩擦角影响较小;当根系含量为0.36%时,黏聚力增加了64.91%;主应力差随应变的增加显著,当轴向变形>2%时,主应力差变化缓慢;试样破坏时表现为剪胀破坏,产生纵向裂缝;随着围压的增大,根土复合体破坏的剪胀效应减弱;初始切线模量随围压及含根量的增大而增大;根土复合体破坏应力比最大值为0.99,最小值为0.63;基于含根量的变化,非线性强度破坏准则反映了根土复合体的破坏特性,破坏包络线在低围压下表现为非线性,高围压下为线性,线性与非线性变化的临界应力与围压的大小有关。
Abstract
To investigate the influence of plant roots on the mechanical properties of root-soil composite, triaxial tests were conducted on root-soil composite with varying root content. The mechanical properties dependent on root content and nonlinear failure criterion of the root-soil composite were analyzed. Results demonstrate that roots enhance the shear strength of the soil by providing tensile strength. Roots primarily impact the cohesion of the rooted soil, while slightly affect the internal friction angle of the root-soil composite. At a root content of 0.36%, the cohesion increased by 64.91%. The principal stress difference increases rapidly at the initial stage of strain, but such change slows down when the axial strain is greater than 2%. The specimen failure is characterized by dilative shear and the formation of longitudinal cracks. Increasing the confining pressure weakens the dilative shear effect of the root-soil composite. The initial tangent modulus increases with increasing confining pressure and root content. The maximum and minimum failure stress ratio of the root-soil composite is 0.99 and 0.63, respectively. The nonlinear strength failure criterion reflects the failure characteristics of the root-soil composite with varying root content. The failure envelope is nonlinear at low confining pressure and linear at high confining pressure, with the critical stress correlated to the confining pressure.
关键词
根土复合体 /
根系含量 /
三轴试验 /
抗剪强度 /
破坏准则
Key words
root-soil composite /
root content /
triaxial test /
shear strength /
failure criterion
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 廖 博, 刘建平, 周花玉. 含根量对秋枫根-土复合体抗剪强度的影响[J]. 水土保持学报, 2021, 35(3): 104-110, 118.
[2] 栗岳洲, 付江涛, 余冬梅, 等. 寒旱环境盐生植物根系固土护坡力学效应及其最优含根量探讨[J]. 岩石力学与工程学报, 2015, 34(7): 1370-1383.
[3] MAKSIMOVIC M.Nonlinear Failure Envelope for Soils[J].Journal of Geotechnical Engineering,1989,115(4):581-586.
[4] ANYAEGBUNAM A J. Nonlinear Power-type Failure Laws for Geomaterials: Synthesis from Triaxial Data, Properties, and Applications[J]. International Journal of Geomechanics, 2015, 15(1): 04014036.1-04014036.16.
[5] XU H, LI T B, CHEN J N, et al. Characteristics and Applications of Ecological Soil Substrate for Rocky Slope Vegetation in Cold and High-altitude Areas[J]. Science of the Total Environment, 2017, 609: 446-455.
[6] MOHSEN E-T, BEHZAD A-A, MOSSA H S. Integrated Impacts of Vegetation and Soil Type on Slope Stability: A Case Study of Kheyrud Forest, Iran[J]. Ecological Modelling, 2021, 446:109498.
[7] WALDRON L J. The Shear Resistance of Root-Permeated Homogeneous and Stratified Soil[J]. Soil Science Society of America Journal, 1977, 41(5): 843-849.
[8] WU T H. Investigation of Landslides on Prince of Wales Island, Alaska, Geotechnical Engineering Report No 5.[R]. Columbus: Ohio State University, 1976: 94.
[9] 张乔艳, 唐丽霞, 潘 露, 等. 喀斯特地区灌木根系力学特性及WU模型适用性研究[J]. 长江科学院院报, 2020, 37(12): 53-58.
[10]KIM J H, FOURCAUD T, JOURDAN C, et al. Vegetation as a Driver of Temporal Variations in Slope Stability: The Impact of Hydrological Processes[J]. Geophysical Research Letters, 2017, 44(10): 4897-4907.
[11]NG C W W, WOON K X, LEUNG A K, et al. Experimental Investigation of Induced Suction Distribution in a Grass-Covered Soil[J]. Ecological Engineering, 2013, 52: 219-223.
[12]方诗圣, 姚 鑫, 谭张琴, 等. 草本植物根系对高液限土的加固效应[J]. 水土保持通报, 2017, 37(3): 43-47.
[13]陈 飞, 钟连祥, 郭 顺, 等. 生态防护技术对稀土矿山边坡的固坡效果[J]. 水土保持通报, 2019, 39(3): 132-136, 143.
[14]蒋希雁, 杨尚青, 冯 峰, 等. 植被根系对土体渗透特性影响的试验研究[J]. 合肥工业大学学报(自然科学版), 2022, 45(3): 370-375.
[15]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.
[16]SCHWARZ M, LEHMANN P, OR D. Quantifying Lateral Root Reinforcement in Steep Slopes-From a Bundle of Roots to Tree Stands[J]. Earth Surface Processes and Landforms, 2010, 35(3): 354-367.
[17]VILLARD P, JOUVE P, RIOU Y. Modelisation du Comportement Mecanique du Texsol[J]. Bulletin Liaison Labo, 1990, 168: 15-27.
[18]DI PRISCO C, NOVA R. A Constitutive Model for Soil Reinforced by Continuous Threads[J]. Geotextiles and Geomembranes, 1993, 12(2): 161-178.
[19]DIAMBRA A, IBRAIM E, MUIR WOOD D, et al. Fibre Reinforced Sands: Experiments and Modelling[J]. Geotextiles and Geomembranes, 2010, 28(3): 238-250.
[20]ZORNBERG J G. Discrete Framework for Limit Equilibrium Analysis of Fibre-Reinforced Soil[J]. Géotechnique, 2002, 52(8): 593-604.
[21]BAKER R. Nonlinear Mohr Envelopes Based on Triaxial Data[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2004, 130(5): 498-506.
[22]GRAY D H, AL-REFEAI T. Behavior of Fabric-Versus Fiber-Reinforced Sand[J]. Journal of Geotechnical Engineering, 1986, 112(8): 804-820.
[23]MACHADO S L, CARVALHO M F, VILAR O M. Constitutive Model for Municipal Solid Waste[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2002, 128(11): 940-951.
[24]王 磊, 朱 斌, 李俊超, 等. 一种纤维加筋土的两相本构模型[J]. 岩土工程学报, 2014, 36(7): 1326-1333.
[25]ZHANG X J, CHEN W F. Stability Analysis of Slopes with General Nonlinear Failure Criterion[J]. International Journal for Numerical and Analytical Methods in Geomechanics, 1987, 11(1): 33-50.
[26]胡田飞, 刘建坤, 常 丹, 等. 冻融循环对粉质黏土力学性质的影响及邓肯-张模型[J]. 中国公路学报, 2018, 31(2): 298-307.
[27]方 薇. 一种非饱和土的非线性抗剪强度包络壳模型[J]. 岩石力学与工程学报, 2018, 37(11): 2601-2609.
基金
国家自然科学基金重大项目(41790432);成都理工大学“研究生拔尖创新人才培育计划”项目(CDUT2023BJCX006)
PDF(4072 KB)
