马尼拉草根系增强土体抗剪强度试验研究与数值模拟  

Experimental study and numerical simulation of soil shear strength enhanced by Manila grass root system

作　　者：刘冬民 李辉[1] 蒋宁山[1] 梁国新 王亚伟 LIU Dongmin;LI Hui;JIANG Ningshan;LIANG Guoxin;WANG Yawei(School of Civil Engineering,Qinghai University,Xining 810016,China;Qinghai Dongce Standard Inspection and Certification Technology Co.,Ltd.,Haidong 810600,China)

机构地区：[1]青海大学土木工程学院,青海西宁810016 [2]青海东测标准检验检测认证科技有限公司,青海海东810600

出　　处：《青海大学学报》2022年第3期93-99,共7页Journal of Qinghai University

基　　金：青海省科学技术厅项目(2020-ZJ-718)。

摘　　要：为了研究草本植被根系的加筋效应,本试验以马尼拉草为试验植被,利用三轴仪器对马尼拉草根土复合体进行室内不固结不排水三轴试验,在不同含水率和含根量条件下,对根土复合体的主应力差—轴向应变关系及抗剪强度指标进行研究,并通过离散元数值模拟PFC2D软件模拟了室内三轴试验。结果表明:(1)随着围压的增大,土体破坏时的主应力差增大,且均呈应变硬化型,无明显峰值。(2)含水率对土体抗剪强度的影响较大,随着含水率的增加,土体破坏时的主应力差受围压和含根量的影响产生变化。(3)相比于素土,马尼拉草根系的加入对土体抗剪强度的增强效应显著,主要体现在黏聚力上。(4)离散元数值模拟结果与室内三轴试验结果较吻合,且通过接触力链图发现,受力的土颗粒数与围压、含根量呈正相关。Manila grass is used as experimental material in order to study the reinforcement effect of root system of herbaceous vegetation.The indoor unconsolidated and undrained triaxial test of root soil complex of Manila grass is carried out by triaxial instrument.The principal stress difference-axial strain relationship and shear strength index of root soil complex are studied under the conditions of different water content and different root content.The indoor triaxial test is simulated by discrete element numerical simulation software PFC2D.The results show that:(1)The principal stress difference of soil failure is larger with the increase of confining pressure.They are strain hardening type without obvious peak value.(2)Water content has a great influence on soil shear strength.The principal stress difference of soil failure is affected by confining pressure and root content.(3)Compared with plain soil,adding Manila grass root system can significantly enhance soil shear strength,which is mainly reflected in cohesion.(4)The results of discrete element numerical simulation are in good agreement with the results of indoor triaxial test.According to the contact force chain diagram,the number of stressed soil particles is positively correlated with confining pressure and root content.

关 键 词：三轴试验 马尼拉草 离散元数值模拟 抗剪强度 含根量 含水率 

分 类 号：TU411.7[建筑科学—岩土工程]