黄土斜坡土体强度特性的三轴试验研究  

Triaxial test for shear strength of loess slope soil

作　　者：何小亮[1,2] 刘潇敏[2] 

机构地区：[1]西北大学地质学系/大陆动力学国家重点试验室,西安710069 [2]中国水电顾问集团西北勘测设计研究院,西安710065

出　　处：《干旱区资源与环境》2014年第8期151-155,共5页Journal of Arid Land Resources and Environment

基　　金：陕西省教育厅专项科研计划项目(09JK780);国家自然科学基金项目(40502028)资助

摘　　要：以陕西泾阳南塬某黄土斜坡第九层（L9）黄土为研究对象,采用常规三轴试验探讨土体在三轴剪切过程中的应力~应变关系、含水率和围压对抗剪强度的影响、粘聚力和内摩擦角随含水率的变化规律等问题。试验成果表明：1）w=5.3%时,L9黄土应力~应变曲线呈应变软化,试样在50KPa、100KPa围压下发生脆性破坏;w=12.3%、19.3%、25%时,应力~应变曲线均表现为应变硬化,试样呈塑性破坏。2）在相同围压下,L9黄土抗剪强度随含水率的增加而减小;含水率从19.3%增加到25%（饱和）时,抗剪强度下降最快,降幅达75%。3）随着含水率的增加,L9黄土的粘聚力和内摩擦角降低;粘聚力在w=5.3%~12.3%阶段内下降最快,降幅达73%;内摩擦角在w=19.3%~25%阶段内下降最快,降幅为60%。研究成果对于今后黄土塬滑坡（边坡）工程治理、监测,尤其是黄土塬边坡安全的早期预测有重要的参考价值。The 9th floor loess （L9） in Southern Jingyang county was chosen as the main object of the study. Tri- axial tests were carried out in order to evaluate the relationship between the stress and the strain in the triaxial shear process. The shear strength properties of the loess through varying the confining pressure and moisture con- tent and the law of cohesive strength and fiction angle with moisture content variation were also discussed. The results show the following findings. 1 ） The stress - strain curve of L9 loess is softening modulus when moisture content is 5.3% and the failure mode of the specimen is brittle failure when confining pressure is 50KPa or IOOKPa. When moisture content is 12.3% , 19.3% or modulus and the failure mode of the specimen is plastic 25 % , the stress - strain curve of L9 loess is hardening failure. 2）The shear strength of L9 loess decreases with the increasing of moisture content in the same confining pressure. Shear strength decreases by 75% with moisture content increases from 19.3% to 25%. 3 ） Both the cohesive strength and the fiction angle reduce with the in- creasing of moisture content. Cohesive strength decreases by 73% with moisture content increases from 5.3% to 12.3%. Fiction angle decreases by 60% with moisture content increases from 19.3% to 25%. The results can be used in loess slope engineering management, monitoring, especially early prediction of slope safety in Loess plateau areas.

关 键 词：黄土 三轴剪切试验 强度特性 

分 类 号：P694[天文地球—地质学]