三维应力下密度对粗粒料力学特性的影响  

Effects of Density on Mechanical Properties of Coarse Granular Material under Three-dimensional Stress

作　　者：姜景山[1,2] 左永振[2] 程展林[2] 潘家军[2] JIANG Jing-shan;ZUO Yong-zhen;CHENG Zhan-lin;PAN Jia-jun(School of Architectural Engineering,Nanjing Institute of Technology,Nanjing 211167,China;Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources,Yangtze River Scientific Research Institute,Wuhan 430010,China)

机构地区：[1]南京工程学院建筑工程学院,南京211167 [2]长江科学院水利部岩土力学与工程重点实验室,武汉430010

出　　处：《长江科学院院报》2021年第1期89-94,共6页Journal of Changjiang River Scientific Research Institute

基　　金：国家重点研发计划项目(2017YFC0404804);国家自然科学基金-雅砻江联合基金重点项目(U1765203);国家自然科学基金面上项目(51679072,51778282);南京工程学院校级科研基金项目(CKJB201706);长江科学院开放研究基金资助项目(CKWV2017510/KY)。

摘　　要：通过4种不同初始干密度的粗粒料大型真三轴等小主应力、等比例加载固结排水剪切试验,研究了密度对三维应力状态下粗粒料力学特性的影响。试验结果表明:小主应力一定时,随着初始干密度的增大,应力曲线逐渐升高变陡,软化性增强,体缩变形减小,剪胀性增强。体变增量与大主应力方向应变增量之比即体变增量比随初始干密度的增大而减小,体变增量比从一正值逐渐减小趋向于0但>0时为应变硬化型;若体变增量比从正值减小到负值,体变从压缩变为膨胀,为应变软化型;到最小值时,体胀变形发展最快,应力达到峰值,对应于破坏状态。孔隙比随平均正应力的增大而单调减小,为硬化型曲线;若孔隙比先减小后增大,为软化型曲线;随着初始干密度的增大,孔隙比降低幅度减小,体缩变形减小,硬化性减弱。强度随初始干密度或小主应力的增大基本呈线性增大。研究成果对充分认识粗粒料的力学性能并科学进行应力变形分析、合理开展设计施工提供参考。The effect of density on mechanical properties of coarse granular material under three-dimensional stress was investigated by using large-scale true triaxial consolidation and drainage shear tests under equal minimum principal stress and equal proportional loading condition of four different initial dry densities.Test results showed that under the same minimum principle stress,the stress curve became higher and steeper with the increase of initial dry density,the softening property increased,the compression deformation decreased and the dilatancy increased.The ratio of volumetric strain increment to the strain increment in the direction of maximum principle stress declined with the increase of initial dry density.Volumetric increment ratio decreased gradually from a positive value and tended towards zero but greater than zero for strain hardening curve.When volumetric strain increment ratio reduced from a positive value to be a negative value,the volumetric strain changed from compression to dilatancy and stress curve belonged to strain softening type.When volumetric strain increment ratio reached the minimum negative value,the expansion developed to the fastest,the stress reached peak corresponding to failure state.For strain hardening curve,void ratio decreased monotonically with the increase of mean normal stress;for strain softening curve,void ratio first decreased and then increased.With the increases of initial dry density,void ratio reduction attenuated,the compression deformation decreased and the hardening property alleviated.The strength grew linearly with the increase of initial dry density or minimum principle stress.

关 键 词：粗粒料 三维应力 大型真三轴试验 初始干密度 力学特性 变形 孔隙比 强度 

分 类 号：TU411[建筑科学—岩土工程]