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| Yield characteristics of Q3 loess in true triaxial tests |
| FANG Jinjin1，SHAO Shengjun1，LI Rong1，FENG Yixin2 |
(1. Institute of Geotechnical Engineering，Xi?an University of Technology，Xi?an，Shaanxi 710048，China；
2. School of Civil Engineering，Henan Polytechnic University，Jiaozhuo，Henan 454000，China) |
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Abstract A series of isotropic consolidation and shear tests under different intermediate principal stress ratio b and constant water content were performed on unsaturated intact loess with various initial suctions using the true triaxial apparatus. The yield curves in the p-s plane and the shear yield curves in the p-q plane of the unsaturated intact loess were studied. A unified expression of suction increase and loading collapse was established in p-s plane. The yielding characteristics of the unsaturated intact loess were discussed under different ratios of b. The yield suction is a constant related to the density and structure of soil. The curve of suction increase and loading collapse was universally described as a parabola. The shear yield curves are arcs in the p-q plane and are part of the yielding cone surfaces in the three-dimensional net principle stress spaces. The yielding surfaces at k0 state in the net principle stress spaces intersect with the circular conical surfaces with the increase of the ratio b，and the unsaturated loess under the condition of k0 yielded with the decrease of the matrix suction and the increase of the intermediate principle stress ratio b.
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[1] ALONSO E. E，GENS A，HIGHT D W. Special problem soils[C]// Proceeding of the 9th European Conference on Soil Mechanics and Foundation Engineering. [S. l.]：[s. n.]，1987：1 087–1 146.
[2] ALONSO E E，GENS A. A constitutive model for partially saturated soils[J]. Geotechnique，1990，40(3)：405–430.
[3] WHEELER S J，SIVAKUMAR V. An elasto-plastic critical state framework for unsaturated soil[J]. Geotechnique，1995，45(1)：35–53.
[4] 陈正汉. 重塑非饱和黄土的变形、强度、屈服和水量变化特性[J]. 岩土工程学报，1999，21(1)：82–90.(CHEN Zhenghan. Deformation，strength，yield and moisture change of a remolded unsaturated loess[J]. Chinese Journal of Geotechnical Engineering，1999，21(1)：82–90. (in Chinese))
[5] DELAGE P，GRAHAM J. Mechanical behavior of unsaturated soils： Understanding the behavior of unsaturated soils requires reliable conceptual models[C]// Proceedings of the First International Conference on Unsaturated Soils. Paris：A. A. Balkerma，1995：1 223–1 256.
[6] SIVAKUMAR V，POUL N. Yielding of the unsaturated soils[C]// Proceedings of The Second International Conference on Unsaturated Soils. Beijing：International Academic Publishers，1998：131–136.
[7] 黄 海，陈正汉，李 刚. 非饱和土在p-s平面上屈服轨迹及土–水特征曲线的探讨[J]. 岩土力学，2000，21(4)：316–321.(HUANG Hai，CHEN Zhenghan，LI Gang. A study on yield locus of unsaturated soils on p-s plane and soil-water characteristic curve[J]. Rock and Soil Mechanics，2000，21(4)：316–321.(in Chinese))
[8] 苗强强，陈正汉，朱青青. p-s平面上不同应力路径的非饱和土力学特性研究[J]. 岩石力学与工程学报，2011，30(7)：1 496–1 501. (MIAO Qiangqiang，CHEN Zhenghan，ZHU Qingqing. Study of mechanics characteristic of unsaturated soils with different stress paths on p-s plane[J]. Chinese Journal of Rock Mechanics and Engineering，2011，30(7)：1 496–1 501.(in Chinese))
[9] CUI Y J，DELAGE P. Yielding and plastic behavior of an unsaturated compacted silt[J]. Geotechnique，1996，46(2)：291–311.
[10] 邵生俊，罗爱忠，邓国华. 一种新型真三轴仪的研制与开发[J]. 岩土工程学报，2009，31(8)：1 172–1 179.(SHAO Shengjun，LUO Aizhong，DENG Guohua. Development of a new true tri-axial apparatus[J]. Chinese Journal of Geotechnical Engineering，2009，31(8)：1 172–1 179.(in Chinese))
[11] 谢定义，齐吉琳. 土结构性及其定量化参数研究的新途径[J]. 岩土工程学报，1999，21(6)：651–656.(XIE Dingyi，QI Jilin. Soil structure characteristics and new approach in research on its quantitative parameter[J]. Chinese Journal of Geotechnical Engineering，1999，21(6)：651–656 (in Chinese))
[12] 谢定义，齐吉琳，朱元林. 土的结构性参数及其与变形－强度的关系[J]. 水利学报，1999，(10)：1–6.(XIE Dingyi，QI Jilin，ZHU Yuanlin. Soil structure parameter and its relations to deformation and strength[J]. Journal of Hydraulic Engineering，1999，(10)：1–6.(in Chinese))
[13] 邵生俊，周飞飞，龙吉勇. 原状黄土结构性及其定量化参数研究[J]. 岩土工程学报，2004，26(4)：531–536.(SHAO Shengjun，ZHOU Feifei，LONG Jiyong. Structural properties of loess and its quantitative parameter[J]. Chinese Journal of Geotechnical Engineering，2004，26(4)：531–536.(in Chinese))
[14] 邵生俊，王丽琴，陶 虎，等. 黄土的构度及其与粒度、密度、湿度之间的关系[J]. 岩土工程学报，2014，36(8)：1 387–1 393. (SHAO Shengjun，WANG Liqin，TAO Hu，et al. Structural index of loess and its relation with granularity，density and humidity[J]. Chinese Journal of Geotechnical Engineering，2014，36(8)：1 387–1 393.(in Chinese))
[15] 党进谦，李 靖. 非饱和黄土的结构强度与抗剪强度[J]. 水利学报，2001，7(7)：79–84.(DANG Jinqian，LI Jing. Structure strength and shear strength of unsaturated loess[J]. Journal of Hydraulic Engineering，2001，7(7)：79–84.(in Chinese))
[16] 骆亚生，谢定义，李 鹏. 非饱和黄土结构特性变化的主要影响因素[J]. 水土保持通报，2005，(2)：36–39.(LUO Yasheng，XIE Dingyi， LI Peng. Main influence factors on structural property changes of unsaturated loess[J]. Bulletin of Soil and Water Conservation，2005，(2)：36–39.(in Chinese))
[17] 陈存礼，何军芳，杨 鹏. 考虑结构性影响的原状黄土本构关系[J]. 岩土力学，2007，28(11)：2 284–2 290.(CHEN Cunli，HE Junfang，YANG Peng. Constitutive relationship of intact loess considering structural effect[J]. Rock and Soil Mechanics，2007，28(11)：2 284–2 290.(in Chinese))
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2016, Vol. 35 
