Citation: | ZHAO Danqi, FU Yukai, HOU Xiaokun, LI Tonglu, LI Ping, LI Yan, ZHANG Lin. Mechanical properties of saturated remolded loess under different stress paths[J]. Hydrogeology & Engineering Geology, 2022, 49(6): 74-80. doi: 10.16030/j.cnki.issn.1000-3665.202201020 |
The mechanical properties of soil often vary with stress state and stress paths. In order to investigate the mechanical properties of saturated soil under vertical loading and constant shear stress path, saturated remolded loess samples are prepared. Through consolidated undrained (CU) triaxial tests and constant shear stress drained (CSD) triaxial tests, the corresponding stress-strain curves, pore water pressure curves and stress path curves are measured. The results show that the saturated remolded loess has obviously different deformation characteristics under the two paths. In CU tests, the stress-strain curves are softening weakly. The pore water pressure rises rapidly and tends to be stable gradually. In CSD tests, the deviator stress is a constant and the pore water pressure is applied. The deformation of samples is small for a long time at the beginning. When the pore water pressure increases to 60%−75% of the confining pressure, the samples are destroyed rapidly. Because there is no peak value of deviator stress in CSD path, the equivalent peak failure line is defined according to the axial strain-mean effective stress curves. By comparison, it is found that the effective peak strength indexes of the saturated remolded loess are significantly different under the two paths. However, the effective residual strength indexes are similar, indicating that the effective residual strength indexes are the internal attribute of the remolded loess and are not affected by the stress path. This study can provide reference for selecting the correct stress path test in practical engineering.
[1] | 李广信,吕禾. 土强度试验的排水条件与强度指标的应用[J]. 工程勘察,2006,34(3):11 − 14. [LI Guangxin,LYU He. Drainage conditions for tests of soil strength and the application of strength indices[J]. Journal of Geotechnical Investigation & Surveying,2006,34(3):11 − 14. (in Chinese with English abstract) |
[2] | 陈存礼,郭娟,杨鹏. 应力路径对固结排水条件下饱和原状黄土变形与强度特性的影响[J]. 水利学报,2008,39(6):703 − 708. [CHEN Cunli,GUO Juan,YANG Peng. Influence of stress path on deformation and strength characteristics of saturated intact loess under drainage condition[J]. Journal of Hydraulic Engineering,2008,39(6):703 − 708. (in Chinese with English abstract) doi: 10.3321/j.issn:0559-9350.2008.06.010 |
[3] | 刘恩龙,沈珠江. 不同应力路径下结构性土的力学特性[J]. 岩石力学与工程学报,2006,25(10):2058 − 2064. [LIU Enlong,SHEN Zhujiang. Mechanical behavior of structured soils under different stress paths[J]. Chinese Journal of Rock Mechanics and Engineering,2006,25(10):2058 − 2064. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-6915.2006.10.017 |
[4] | 曾玲玲,陈晓平. 软土在不同应力路径下的力学特性分析[J]. 岩土力学,2009,30(5):1264 − 1270. [ZENG Lingling,CHEN Xiaoping. Analysis of mechanical characteristics of soft soil under different stress paths[J]. Rock and Soil Mechanics,2009,30(5):1264 − 1270. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-7598.2009.05.012 |
[5] | 高彬,陈筠,杨恒,等. 红黏土在不同应力路径下的力学特性试验研究[J]. 地下空间与工程学报,2018,14(5):1202 − 1212. [GAO Bin,CHEN Jun,YANG Heng,et al. Experimental study on mechanical properties of red clay under different stress paths[J]. Chinese Journal of Underground Space and Engineering,2018,14(5):1202 − 1212. (in Chinese with English abstract) |
[6] | 郅彬,王番,胡梦玲,等. 不同应力路径下饱和黄土应力应变及孔压特性分析[J]. 科学技术与工程,2016,16(22):244 − 248. [ZHI Bin,WANG Pan,HU Mengling,et al. The influence of different stress path on stress and strain relation and pore pressure characteristic of saturated loess[J]. Science Technology and Engineering,2016,16(22):244 − 248. (in Chinese with English abstract) doi: 10.3969/j.issn.1671-1815.2016.22.044 |
[7] | 刘祖德,陆士强,杨天林,等. 应力路径对填土应力应变关系的影响及其应用[J]. 岩土工程学报,1982,4(4):45 − 55. [LIU Zude,LU Shiqiang,YANG Tianlin,et al. The influence of stress path on the stress-strain behavior of earthfills and its application[J]. Chinese Journal of Geotechnical Engineering,1982,4(4):45 − 55. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.1982.04.004 |
[8] | 孙岳崧,濮家骝,李广信. 不同应力路径对砂土应力-应变关系影响[J]. 岩土工程学报,1987,9(6):78 − 88. [SUN Yuesong,PU Jialiu,LI Guangxin. The influence of different stress path on the stress-strain relationships of sand[J]. Chinese Journal of Geotechnical Engineering,1987,9(6):78 − 88. (in Chinese) doi: 10.3321/j.issn:1000-4548.1987.06.009 |
[9] | 江美英,骆亚生,王瑞瑞,等. 应力路径对饱和黄土孔压的影响研究[J]. 地下空间与工程学报,2010,6(3):498 − 502. [JIANG Meiying,LUO Yasheng,WANG Ruirui,et al. Influence of stress path on the pore pressure of saturated loess[J]. Chinese Journal of Underground Space and Engineering,2010,6(3):498 − 502. (in Chinese with English abstract) |
[10] | 许成顺,文利明,杜修力,等. 不同应力路径条件下的砂土剪切特性试验研究[J]. 水利学报,2010,41(1):108 − 112. [XU Chengshun,WEN Liming,DU Xiuli,et al. Experimental study on shear behaviors of sand under different stress path[J]. Journal of Hydraulic Engineering,2010,41(1):108 − 112. (in Chinese with English abstract) |
[11] | 周飞,许强,巨袁臻,等. 黑方台黄土斜坡变形破坏机理研究[J]. 水文地质工程地质,2017,44(1):157 − 163. [ZHOU Fei,XU Qiang,JU Yuanzhen,et al. A study of the deformation and failure mechanism of the Heifangtai loess slope[J]. Hydrogeology & Engineering Geology,2017,44(1):157 − 163. (in Chinese with English abstract) |
[12] | 许强,魏勇,彭大雷,等. 泾阳南塬蒋刘4#滑坡特征及成因机制[J]. 水文地质工程地质,2018,45(1):123 − 130. [XU Qiang,WEI Yong,PENG Dalei,et al. Characteristics and failure mechanism of the Jiangliu 4# landslide in the southern tableland in Jingyang County[J]. Hydrogeology & Engineering Geology,2018,45(1):123 − 130. (in Chinese with English abstract) |
[13] | BRAND E W. Some thoughts on rain-induced slope failure[C]//Proceedings of 10th International Conference on Soil Mechanics and Foundation Engineering. Stockholm: A ABalkema, 1981: 373 − 376. |
[14] | 戴福初,陈守义,李焯芬. 从土的应力应变特性探讨滑坡发生机理[J]. 岩土工程学报,2000,22(1):127 − 130. [DAI Fuchu,CHEN Shouyi,LI Zhuofen. Analysis of landslide initiative mechanism based on stress-strain behavior of soil[J]. Chinese Journal of Geotechnical Engineering,2000,22(1):127 − 130. (in Chinese) doi: 10.3321/j.issn:1000-4548.2000.01.023 |
[15] | CHU J,LEROUEIL S,LEONG W K. Unstable behaviour of sand and its implication for slope instability[J]. Canadian Geotechnical Journal,2003,40(5):873 − 885. doi: 10.1139/t03-039 |
[16] | 赵春宏,戴福初. 深圳某填土滑坡破坏机理研究[J]. 中国地质灾害与防治学报,2007,18(2):1 − 8. [ZHAO Chunhong,DAI Fuchu. Study on failure mechanism of a fill slope in Shenzhen[J]. The Chinese Journal of Geological Hazard and Control,2007,18(2):1 − 8. (in Chinese with English abstract) doi: 10.3969/j.issn.1003-8035.2007.02.001 |
[17] | 董全杨,蔡袁强,王军,等. 松散砂土不稳定性试验研究[J]. 岩石力学与工程学报,2014,33(3):623 − 630. [DONG Quanyang,CAI Yuanqiang,WANG Jun,et al. Experimental study of instability of loose sand[J]. Chinese Journal of Rock Mechanics and Engineering,2014,33(3):623 − 630. (in Chinese with English abstract) |
[18] | 徐张建,林在贯,张茂省. 中国黄土与黄土滑坡[J]. 岩石力学与工程学报,2007,26(7):1297 − 1312. [XU Zhangjian,LIN Zaiguan,ZHANG Maosheng. Loess in China and loess landslides[J]. Chinese Journal of Rock Mechanics and Engineering,2007,26(7):1297 − 1312. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-6915.2007.07.001 |
[19] | 中华人民共和国建设部. 土的工程分类标准: GB/T 50145—2007[S]. 北京: 中国计划出版社, 2008 Ministry of Construction of the People’s Republic of China. Standard for engineering classification of soil: GB/T 50145—2007[S]. Beijing: China Planning Press, 2008. (in Chinese) |
[20] | 中华人民共和国住房和城乡建设部. 土工试验方法标准: GB/T 50123—2019[S]. 北京: 中国计划出版社, 2019 Ministry of Housing and Urban-Rural Development of the People’s Republic of China. Standard for geotechnical testing method: GB/T 50123—2019[S]. Beijing: China Planning Press, 2019. (in Chinese) |
[21] | 李广信, 张丙印, 于玉贞. 土力学[M]. 2版. 北京: 清华大学出版社, 2013 LI Guangxin, ZHANG Bingyin, YU Yuzhen. Soil mechanics[M]. 2nd ed. Beijing: Tsinghua University Press, 2013. (in Chinese) |
Particle size distribution curve of the loess sample
Stress path of the consolidated undrained tests
Curves of q-ɛa and u-ɛa
Swelling failure of the soil samples under both stress paths
Stress path of the constant shear drained tests and ɛa-p' curves
Curves of u-ɛa
Failure lines of two stress paths