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。
Abstract
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
Key words
coarse granular material /
three-dimensional stress /
large-scale true triaxial test /
initial dry density /
mechanical property /
deformation /
void ratio /
strength
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参考文献
[1] CHU J. An Experimental Examination of the Critical State and Other Similar Concepts for Granular Soils[J]. Canadian Geotechnical Journal, 1995, 32(6):1065-1075.
[2] 宋 飞,张建民.各向异性砂土渐进状态试验研究[J].岩土工程学报,2010,32(4):551-561.
[3] 蔡正银,侯贺营,张晋勋,等.考虑颗粒破碎影响的珊瑚砂临界状态与本构模型研究[J].岩土工程学报, 2019,41(6):989-995.
[4] LI X S, WANG Y. Linear Representation of Steady-state Line for Sand[J]. Journal of Geotechnical and Geoenvironmental Engineering, 1998, 124(12): 1215-1217.
[5] VERDUGO R, ISHIHARA K. The Steady State of Sandy Soils[J]. Soils and Foundations, 1996, 36(2): 81-91.
[6] 蔡正银,李相菘.砂土的剪胀理论及其本构模型的发展[J].岩土工程学报,2007,29(8):1122-1128.
[7] BEEN K, JEFERIES M G. A State Parameter for Sands[J]. Geotechnique, 1985, 35(2): 99-112.
[8] WOOD D M, BELKHEIR K, LIU D F. Strain Softening and State Parameter for Sand Modeling[J]. Geotechnique, 1994, 44(2): 335-339.
[9] 姚仰平,余亚妮.基于统一硬化参数的砂土临界状态本构模型[J].岩土工程学报,2011,33(12): 1827-1832.
[10]张卫华,赵成刚,傅 方.饱和砂土相变状态边界面本构模型[J].岩土工程学报,2013,35(5):930-939.
[11]WAN R G, GUO P J. A Pressure and Density Dependent Dilatancy Model for Granular Materials[J]. Soils and Foundations, 1999, 39(6): 1-12.
[12]LI X S, DAFALIAS Y F, WANG Z L. State-dependentDilatancy in Critical-state Constitutive Modeling of Sand[J]. Canadian Geotechnical Journal, 1999, 36: 599-611.
[13]LI X S. A Sand Model with State-dependent Dilatancy[J]. Geotechnique, 2002, 52(3): 173-186.
[14]孙吉主,罗新文.考虑剪胀性与状态相关的钙质砂双屈服面模型研究[J].岩石力学与工程学报,2006,25(10): 2145-2149.
[15]黄茂松,李学丰,贾苍琴.基于材料状态相关临界状态理论的砂土双屈服面模型[J].岩土工程学报,2010,32(11): 1766-1771.
[16]姜景山,刘汉龙,程展林,等.密度和围压对粗粒土力学性质的影响[J].raybet体育在线
院报,2009,26(8):46-50.
[17]丁树云,蔡正银,凌 华.堆石料的强度与变形特性及临界状态研究[J].岩土工程学报,2010,32(2):248-252.
[18]刘恩龙,陈生水,李国英,等.堆石料的临界状态与考虑颗粒破碎的本构模型[J].岩土力学,2011,32(增刊2):148-154.
[19]刘斯宏,沈超敏,毛航宇,等.堆石料状态相关弹塑性本构模型[J].岩土力学,2019,40(8):2891-2898.
[20]DL/T 5356—2006,水电水利工程粗粒土试验规程[S]. 北京:中国电力出版社,2008.
[21]潘家军,程展林,余 挺,等.不同中主应力条件下粗粒土应力变形特性试验研究[J].岩土工程学报,2016,38(11): 2078-2084.
[22]姜景山,程展林,左永振,等.三维应力状态下粗粒料强度特性试验研究[J].岩土力学,2018,39(10):3581-3588.
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);raybet体育在线
开放研究基金资助项目(CKWV2017510/KY)
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