摘要
【目的】我国东北松嫩平原上广泛分布着分散性黏土,其极易引发严重的水利工程破坏问题。故以揭示相关破坏模式和机理为目的,开展分散性黏土力学特性试验,指导水利工程的科学治理。【方法】基于分散性黏土破坏所处真实应力路径,采用平面应变状态下的力学试验方法,对分散性黏土的强度进行研究。【结果】①平面应变状态下,分散性黏土应力-应变曲线呈硬化型,在固结应力50 kPa下的强度与常规三轴下弱软化型的相差2倍左右;中主应力-应变关系为硬化型,两者之间近似呈线性关系。②在低固结应力下,分散性黏土中主应力系数达到0.44,中主应力对土体强度影响不能被忽略,其破坏形态呈鼓胀且无明显的空间剪切带;但在高固结应力下,破坏形态具有剪切带且位置处于对角线。③分散性黏土的强度因土体化学离子流出而被削弱,在不同固结应力作用下表现出不同的压硬性和强度。【结论】我国东北松嫩平原上土的分散性严重削弱了土的力学强度,土体强度的下降造成分散性黏土堤防的滑坡破坏。
【Objective】In order to address the severe damage to hydraulic projects caused by the widespread distribution of dispersive clay in the Songnen Plain of Northeast China,this study aims to reveal the associated failure patterns and mechanisms,thereby guiding the scientific management of hydraulic projects.【Methods】In this study,based on the real stress path of dispersive clay failure,a mechanical experimental method under plane strain conditions was adopted to investigate the strength properties of dispersive clay.【Results】(1)The results showed that under plane strain conditions,the stress-strain curve of dispersive clay exhibited the strain hardening type,distinct from the conventional strain softening type under triaxial conditions,and the strength difference was approximately twice at a consolidation stress of 50 kPa.The relationship between intermediate principal stress and strain also showed the strain hardening type,and was approximately linear.(2)Under low consolidation stress,the coefficient of the intermediate principal stress reached 0.44,indicating a significant influence on the strength of the soil.The failure mode of dispersive clay was characterized by swelling with no obvious spatial shear band,while under high consolidation stress,the failure mode exhibited a shear band located diagonally.(3)Additionally,the strength properties of dispersive clay were weakened by the leaching of chemical ions in the soil,showing different compaction and strength under different consolidation stresses.【Conclusion】The dispersivity of clays in the Songnen Plain of Northeast China severely weakens their mechanical strength.The reduction in clay strength leads to slope failures in dispersive clay embankments.
作者
薛苗苗
何影
王理想
王淼
XUE Miaomiao;HE Ying;WANG Lixiang;WANG Miao(College of Engineering,Zhengzhou Technology and Business University,Zhengzhou 451450,China;School of Architecture and Civil Engineering,Huangshan University,Huangshan 245000,China;Anhui and Huaihe River Institute of Hydraulic Research,Hefei 233000,China;Heilongjiang Province Hydraulic Research Institute,Harbin 150086,China)
出处
《华北水利水电大学学报(自然科学版)》
北大核心
2025年第5期151-160,共10页
Journal of North China University of Water Resources and Electric Power:Natural Science Edition
基金
黑龙江省重点研发计划项目(JD2023SJ46)
国家自然科学基金项目(42401175)
安徽省(水利部淮委)水利科学研究院科技攻关计划项目(KJGG202302)
安徽省自然科学基金“水科学”联合基金项目(2208085US01)。
关键词
分散性黏土
平面应变
力学强度
中主应力
dispersive clay
plane strain
mechanical strength
intermediate principal stress
