EFFECTS OF POISSON'S RATIO ON FAILURE MODE AND OVERALL DEFORMATIONAL CHARACTERISTICS OF A ROCK SPECIMEN
-
摘要:
利用编写的计算岩样全部变形特征的FISH函数, 采用FLAC模拟了泊松比不同时单缺陷岩石试样的破坏及全部变形特征。在峰前及峰后, 本构模型分别取为线弹性模型及莫尔库仑剪破坏与拉破坏复合的应变软化模型。高泊松比使岩样发生由单一剪切破坏向复杂破坏转变、破坏区域的面积增加、剪切带倾角降低, Coulomb、Roscoe及Arthur理论对此无法解释。不同泊松比时计算得到的峰前应力-轴向应变曲线、应力-侧向应变曲线、侧向应变-轴向应变曲线、体积应变-轴向应变曲线的线性阶段与平面应变压缩条件下的线弹性解吻合。若泊松比超过1/3, 通过计算得到的平面应变压缩泊松比可大于0.5, 这被数值模拟确认。泊松比的增加使峰后的侧向应变-轴向应变曲线、体积应变-轴向应变曲线、计算得到的泊松比-轴向应变曲线变得不陡峭, 使峰后的应力-侧向应变曲线变得陡峭, 使破坏的前兆变得不明显。
Abstract:Using FISH functions written in FLAC to calculate the overall deformational characteristics, the effects of Poisson's ratio in the elastic stage on the failure mode and overall deformational characteristics were modeled for a rock specimen with a material imperfection in plane strain compression. In the elastic stage, the adopted constitutive relation of rock was linear elastic; and in the strainsoftening stage, a composite Mohr-Coulomb criterion with tension cut-off was used and the post-peak constitutive relation was also linear.The increased Poisson's ratio in the elastic stage leads to a transition of failure mode from single to complex shear fractures and a larger failed area is expected.The predicted shear band inclination is lower at a higher Poisson's ratio in the elastic stage, which cannot be explained by Coulomb, Roscoe and Arthur theories.Prior to the peak stress, the calculated slopes of the linear stress-axial strain curves, stress-lateral strain curves, lateral strain-axial strain curves and volumetric strain-axial strain curves at different Poisson's ratios in the elastic stage are consistent with the linear elastic solutions in plane strain compression.The calculated Poisson's ratio in plane strain compression is higher than 0.5 if the adopted Poisson's ratio in the elastic stage exceeds 1/3, as is confirmed by the present numerical simulation.At a higher Poisson's ratio in the elastic stage, the post-peak lateral strain-axial strain curve, volumetric strain-axial strain curve and calculated Poisson's ratio-axial strain curve become less steep; whereas the post-peak stress-lateral strain curve becomes steep and the precursor to failure is less apparent.
-
Key words:
- Poisson's ratio /
- strain localization /
- precursor /
- stress /
- lateral strain /
- volumetric strain
-
-
[1] 范庆忠, 高延法.分级加载条件下岩石流变特性的试验研究[J].岩土工程学报, 2005, 27 (11):1273~1276. doi: 10.3321/j.issn:1000-4548.2005.11.008
[2] 朱俊高, 卢海华, 殷宗泽.土体侧向变形性状的真三轴试验研究[J].河海大学学报, 1995, 23 (6):28~33. doi: 10.3321/j.issn:1000-1980.1995.06.006
[3] 朱建明, 徐秉业, 岑章志.岩石类材料峰后滑移剪胀变形特征研究[J].力学与实践, 2001, 23 (5):19~22. doi: 10.3969/j.issn.1000-0879.2001.05.004
[4] 孙益振, 邵龙谭.基于局部与整体变形测量的粉土泊松比试验研究[J].岩土工程学报, 2006, 28 (8):1033~ 1038. doi: 10.3321/j.issn:1000-4548.2006.08.020
[5] Gold LW.On the elasticity of ice plates[J].Canada Journal of Civil Engineering, 1988, 15 (6):1080~1084. doi: 10.1139/l88-140
[6] 王学滨.岩样单轴压缩峰后泊松比理论研究[J].工程力学, 2006, 23 (4):99~103. doi: 10.3969/j.issn.1000-4750.2006.04.018
[7] 王学滨, 马剑, 刘杰, 等.基于梯度塑性本构理论的岩样侧向变形分析(Ⅰ):基本理论及本构参数对侧向变形的影响[J].岩土力学, 2004, 25 (6):904~908. doi: 10.3969/j.issn.1000-7598.2004.06.013
[8] 王学滨, 刘杰, 王雷, 等.基于梯度塑性本构理论的岩样侧向变形分析(Ⅱ):尺寸效应及弹性会跳[J].岩土力学, 2004, 25 (7):1127~1130. doi: 10.3969/j.issn.1000-7598.2004.07.026
[9] 王学滨.岩样单轴压缩轴向及侧向变形耗散能量及稳定性分析[J].岩石力学与工程学报, 2005, 24 (5):846~ 853. doi: 10.3321/j.issn:1000-6915.2005.05.020
[10] 王学滨, 潘一山.基于梯度塑性理论的岩样单轴压缩扩容分析[J].岩石力学与工程学报, 2004, 23 (5):721~ 724. doi: 10.3321/j.issn:1000-6915.2004.05.003
[11] 王学滨.单轴压缩岩样轴向回跳及侧向回跳理论研究[J].岩土力学, 2006, 27 (3):414~417. doi: 10.3969/j.issn.1000-7598.2006.03.015
[12] Wang Xuebin. Analytical solution of complete stress-strain curve in uniaxial compression based on gradient-dependent plasticity [A]. In: Eurock 2005-Impact of Human Activity on the Geological Environment[C]. Taylor &Francis Group, London, 2005, 661~667.
https://www.onepetro.org/conference-paper/ISRM-EUROCK-2005-106 [13] Wang XB. Unified instability criterion for quasibrittle material in uniaxial tension, direct shear and uniaxial compression subjected to shear failure[A]. In: Euro-C Conference 2006-Computational Modelling of Concrete Structures[C]. Taylor & Francis Group, London, 2006, 467~472.
https://www.researchgate.net/publication/289215280_Unified_instability_criterion_for_quasibrittle_material_in_uniaxial_tension_direct_shear_and_uniaxial_compression_subjected_to_shear_failure [14] 王学滨.剪胀对岩样全部变形特征的影响[J].四川大学学报(工程科学版), 2005, 37 (5):25~30. doi: 10.3969/j.issn.1009-3087.2005.05.006
[15] 王学滨.软化模量对岩样全部变形特征的影响[J].岩土工程学报, 2006, 28 (5):600~605. doi: 10.3321/j.issn:1000-4548.2006.05.010
[16] 王学滨.弹性模量对岩样破坏前兆及全部变形特征的影响[J].岩土力学, 2006, 27 (增):559~563. http://d.old.wanfangdata.com.cn/Conference/6322489
[17] Vardoulakis I.Shear band inclination and shear modulus of sand in biaxial tests[J].International Journal for Numerical and Analytical Methods in Geomechanics, 1980, 4 (2):103~119. doi: 10.1002/(ISSN)1096-9853
[18] Vermeer PA.The orientation of shear bands in biaxial tests[J].Géotechnique, 1990, 40 (2):223~236. doi: 10.1680/geot.1990.40.2.223
-
下载:
图(7)
计量
- 文章访问数: 368
- PDF下载数: 2
- 施引文献: 0