Citation: | LI Guanyang, GU Kai, WANG Xiang, SHI Bin. An experimental study of the unconfined compressive strength characteristics of the expansive soil with cracks[J]. Hydrogeology & Engineering Geology, 2022, 49(4): 62-70. doi: 10.16030/j.cnki.issn.1000-3665.202111033 |
Expansive soil is prone to develop a large number of cracks, which have a significant impact on its engineering properties. A prefabricated crack method of expansive soil samples is introduced to carry out the unconfined compression strength on the expansive soil samples under the specific crack morphology. The influence of the crack morphology on the strength characteristics of the expansive soil is examined, and the mechanism of crack action is revealed. The results show that: (1) The crack morphology has a significant effect on the failure mode of the samples. When the cracks become wider, which are perpendicular to the stress direction, the failure mode changes from shear-tensile failure to tensile failure. When the cracks parallel to the stress direction become more and more, the failure mode changes from shear failure to swelling failure. (2) The shape of the cracks perpendicular to the stress direction has a significant effect on the stress-strain relationship of the expansive soil samples. The wider the crack is, the greater the closed strain is. The deeper the crack is, the smaller the initial crack initiation stress is and the greater the strength increment is. The shape of cracks parallel to the stress direction has no obvious effect on the stress-strain relationship. Based on the results, four types of curves are divided, namely, the multi-level rise, fluctuation rise, multi-level decline and standard curve. (3) The direction of crack obviously affects the strength reduction of the cracked soil. The peak strength of the sample containing cracks parallel to the stress direction is close to that of the non-cracked sample. The peak strength and deformation modulus of the sample containing cracks perpendicular to the stress direction decrease with the increasing crack number, and have a good logarithmic function relationship. The peak strain is less affected by crack. This study can provide a theoretical basis for the shallow instability mechanism of the expansive soil slope, and a guidance for the design and construction of the corresponding cracked soil engineering.
[1] | MORRIS P H, GRAHAM J, WILLIAMS D J. Cracking in drying soils[J]. Canadian Geotechnical Journal,1992,29(2):263 − 277. doi: 10.1139/t92-030 |
[2] | HEWITT P J, PHILIP L K. Problems of clay desiccation in composite lining systems[J]. Engineering Geology,1999,53(2):107 − 113. doi: 10.1016/S0013-7952(99)00023-X |
[3] | HT RAYHANI M, YANFUL E K, FAKHER A. Desiccation-induced cracking and its effect on the hydraulic conductivity of clayey soils from Iran[J]. Canadian Geotechnical Journal,2007,44(3):276 − 283. doi: 10.1139/t06-125 |
[4] | 陈铁林, 邓刚, 陈生水, 等. 裂隙对非饱和土边坡稳定性的影响[J]. 岩土工程学报,2006,28(2):210 − 215. [CHEN Tielin, DENG Gang, CHEN Shengshui, et al. Effects of fissures on stability of unsaturated soil slope[J]. Chinese Journal of Geotechnical Engineering,2006,28(2):210 − 215. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.2006.02.013 CHEN Tielin, DENG Gang, CHEN Shengshui, et al. Effects of fissures on stability of unsaturated soil slope[J]. Chinese Journal of Geotechnical Engineering, 2006, 28(2): 210-215. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.2006.02.013 |
[5] | 殷宗泽, 袁俊平, 韦杰, 等. 论裂隙对膨胀土边坡稳定的影响[J]. 岩土工程学报,2012,34(12):2155 − 2161. [YIN Zongze, YUAN Junping, WEI Jie, et al. Influences of fissures on slope stability of expansive soil[J]. Chinese Journal of Geotechnical Engineering,2012,34(12):2155 − 2161. (in Chinese with English abstract) YIN Zongze, YUAN Junping, WEI Jie, et al. Influences of fissures on slope stability of expansive soil[J]. Chinese Journal of Geotechnical Engineering, 2012, 34(12): 2155-2161. (in Chinese with English abstract) |
[6] | 陈守义. 考虑入渗和蒸发影响的土坡稳定性分析方法[J]. 岩土力学,1997,18(2):8 − 12. [CHEN Shouyi. A method of stability analysis taken effects of infiltration and evaporation into consideration for soil slopes[J]. Rock and Soil Mechanics,1997,18(2):8 − 12. (in Chinese with English abstract) CHEN Shouyi. A method of stability analysis taken effects of infiltration and evaporation into consideration for soil slopes[J]. Rock and Soil Mechanics, 1997, 18(2): 8-12. (in Chinese with English abstract) |
[7] | 姚海林, 郑少河, 陈守义. 考虑裂隙及雨水入渗影响的膨胀土边坡稳定性分析[J]. 岩土工程学报,2001,23(5):606 − 609. [YAO Hailin, ZHENG Shaohe, CHEN Shouyi. Analysis on the slope stability of expansive soils considering cracks and infiltration of rain[J]. Chinese Journal of Geotechnical Engineering,2001,23(5):606 − 609. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.2001.05.019 YAO Hailin, ZHENG Shaohe, CHEN Shouyi. Analysis on the slope stability of expansive soils considering cracks and infiltration of rain[J]. Chinese Journal of Geotechnical Engineering, 2001, 23(5): 606-609. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.2001.05.019 |
[8] | 王保田, 张福海. 膨胀土的改良技术与工程应用[M]. 北京: 科学出版社, 2008 WANG Baotian, ZHANG Fuhai. Improvement technology and engineering application of expansive soil[M]. Beijing: Science Press, 2008. (in Chinese) |
[9] | 包承纲. 非饱和土的性状及膨胀土边坡稳定问题[J]. 岩土工程学报,2004,26(1):1 − 15. [BAO Chenggang. Behavior of unsaturated soil and stability of expansive soil slope[J]. Chinese Journal of Geotechnical Engineering,2004,26(1):1 − 15. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.2004.01.001 BAO Chenggang. Behavior of unsaturated soil and stability of expansive soil slope[J]. Chinese Journal of Geotechnical Engineering, 2004, 26(1): 1-15. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.2004.01.001 |
[10] | 刘特洪. 工程建设中的膨胀土问题[M]. 北京: 中国建筑工业出版社, 1997 LIU Tehong. Expansive soil problem in engineering construction[M]. Beijing: China Architecture & Building Press, 1997. (in Chinese) |
[11] | 徐彬, 殷宗泽, 刘述丽. 膨胀土强度影响因素与规律的试验研究[J]. 岩土力学,2011,32(1):44 − 50. [XU Bin, YIN Zongze, LIU Shuli. Experimental study of factors influencing expansive soil strength[J]. Rock and Soil Mechanics,2011,32(1):44 − 50. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-7598.2011.01.008 XU Bin, YIN Zongze, LIU Shuli. Experimental study of factors influencing expansive soil strength[J]. Rock and Soil Mechanics, 2011, 32(1): 44-50. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-7598.2011.01.008 |
[12] | 袁俊平, 殷宗泽. 膨胀土裂隙的量化指标与强度性质研究[J]. 水利学报,2004,35(6):108 − 113. [YUAN Junping, YIN Zongze. Quantitative index of fissure and strength characteristics of fissured expansive soils[J]. Journal of Hydraulic Engineering,2004,35(6):108 − 113. (in Chinese with English abstract) doi: 10.3321/j.issn:0559-9350.2004.06.019 YUAN Junping, YIN Zongze. Quantitative index of fissure and strength characteristics of fissured expansive soils[J]. Journal of Hydraulic Engineering, 2004, 35(6): 108-113. (in Chinese with English abstract) doi: 10.3321/j.issn:0559-9350.2004.06.019 |
[13] | 唐朝生, 施斌, 刘春, 等. 黏性土在不同温度下干缩裂缝的发展规律及形态学定量分析[J]. 岩土工程学报,2007,29(5):743 − 749. [TANG Chaosheng, SHI Bin, LIU Chun, et al. Developing law and morphological analysis of shrinkage cracks of clayey soil under different temperatures[J]. Chinese Journal of Geotechnical Engineering,2007,29(5):743 − 749. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.2007.05.018 TANG Chaosheng, SHI Bin, LIU Chun, et al. Developing law and morphological analysis of shrinkage cracks of clayey soil under different temperatures[J]. Chinese Journal of Geotechnical Engineering, 2007, 29(5): 743-749. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.2007.05.018 |
[14] | 刘春, 王宝军, 施斌, 等. 基于数字图像识别的岩土体裂隙形态参数分析方法[J]. 岩土工程学报,2008,30(9):1383 − 1388. [LIU Chun, WANG Baojun, SHI Bin, et al. Analytic method of morphological parameters of cracks for rock and soil based on image processing and recognition[J]. Chinese Journal of Geotechnical Engineering,2008,30(9):1383 − 1388. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.2008.09.021 LIU Chun, WANG Baojun, SHI Bin, et al. Analytic method of morphological parameters of cracks for rock and soil based on image processing and recognition[J]. Chinese Journal of Geotechnical Engineering, 2008, 30(9): 1383-1388. (in Chinese with English abstract) doi: 10.3321/j.issn:1000-4548.2008.09.021 |
[15] | 唐朝生, 施斌, 崔玉军. 土体干缩裂隙的形成发育过程及机理[J]. 岩土工程学报,2018,40(8):1415 − 1423. [TANG Chaosheng, SHI Bin, CUI Yujun. Behaviors and mechanisms of desiccation cracking of soils[J]. Chinese Journal of Geotechnical Engineering,2018,40(8):1415 − 1423. (in Chinese with English abstract) TANG Chaosheng, SHI Bin, CUI Yujun. Behaviors and mechanisms of desiccation cracking of soils[J]. Chinese Journal of Geotechnical Engineering, 2018, 40(8): 1415-1423. (in Chinese with English abstract) |
[16] | 林銮, 唐朝生, 程青, 等. 基于数字图像相关技术的土体干缩开裂过程研究[J]. 岩土工程学报,2019,41(7):1311 − 1318. [LIN Luan, TANG Chaosheng, CHENG Qing, et al. Desiccation cracking bebavior of soils based on digital image correlation technique[J]. Chinese Journal of Geotechnical Engineering,2019,41(7):1311 − 1318. (in Chinese with English abstract) LIN Luan, TANG Chaosheng, CHENG Qing, et al. Desiccation cracking bebavior of soils based on digital image correlation technique[J]. Chinese Journal of Geotechnical Engineering, 2019, 41(7): 1311-1318. (in Chinese with English abstract) |
[17] | 骆赵刚, 汪时机, 杨振北. 膨胀土湿干胀缩裂隙演化及其定量分析[J]. 岩土力学,2020,41(7):2313 − 2323. [LUO Zhaogang, WANG Shiji, YANG Zhenbei. Quantitative analysis of fracture evolution of expansive soils under wetting-drying cycles[J]. Rock and Soil Mechanics,2020,41(7):2313 − 2323. (in Chinese with English abstract) LUO Zhaogang, WANG Shiji, YANG Zhenbei. Quantitative analysis of fracture evolution of expansive soils under wetting-drying cycles[J]. Rock and Soil Mechanics, 2020, 41(7): 2313-2323. (in Chinese with English abstract) |
[18] | 韦秉旭, 刘斌, 刘雄. 膨胀土裂隙定量化基本指标研究[J]. 水文地质工程地质,2015,42(5):84 − 89. [WEI Bingxu, LIU Bin, LIU Xiong. Research on the quantitative basic index of expansive soil cracks[J]. Hydrogeology & Engineering Geology,2015,42(5):84 − 89. (in Chinese with English abstract) WEI Bingxu, LIU Bin, LIU Xiong. Research on the quantitative basic index of expansive soil cracks[J]. Hydrogeology & Engineering Geology, 2015, 42(5): 84-89. (in Chinese with English abstract) |
[19] | 陈开圣. 干湿循环下红黏土裂隙演化规律及对抗剪强度影响[J]. 水文地质工程地质,2018,45(1):89 − 95. [CHEN Kaisheng. Evolution of cracks in red clay under wetting-drying cycles and its influence on shear strength[J]. Hydrogeology & Engineering Geology,2018,45(1):89 − 95. (in Chinese with English abstract) CHEN Kaisheng. Evolution of cracks in red clay under wetting-drying cycles and its influence on shear strength[J]. Hydrogeology & Engineering Geology, 2018, 45(1): 89-95. (in Chinese with English abstract) |
[20] | 韦秉旭, 黄震, 高兵. 压实膨胀土表面裂隙发育规律及与强度关系研究[J]. 水文地质工程地质,2015,42(1):100 − 105. [WEI Bingxu, HUANG Zhen, GAO Bing. Research on the relationship between fracture development rules and strength of the compacted expansive soil[J]. Hydrogeology & Engineering Geology,2015,42(1):100 − 105. (in Chinese with English abstract) WEI Bingxu, HUANG Zhen, GAO Bing. Research on the relationship between fracture development rules and strength of the compacted expansive soil[J]. Hydrogeology & Engineering Geology, 2015, 42(1): 100-105. (in Chinese with English abstract) |
[21] | 黄震, 陈铖. 改良膨胀土胀缩裂隙及与抗剪强度的关系研究[J]. 水文地质工程地质,2016,43(3):87 − 93. [HUANG Zhen, CHEN Cheng. A study of the swelling shrinkage cracks of the modified expansive soil and its relationship with the shear strength[J]. Hydrogeology & Engineering Geology,2016,43(3):87 − 93. (in Chinese with English abstract) HUANG Zhen, CHEN Cheng. A study of the swelling shrinkage cracks of the modified expansive soil and its relationship with the shear strength[J]. Hydrogeology & Engineering Geology, 2016, 43(3): 87-93. (in Chinese with English abstract) |
[22] | 刘宽, 叶万军, 高海军, 等. 干湿环境下膨胀土力学性能劣化的多尺度效应[J]. 岩石力学与工程学报,2020,39(10):2148 − 2159. [LIU Kuan, YE Wanjun, GAO Haijun, et al. Multi-scale effects of mechanical property degradation of expansive soils under drying-wetting environments[J]. Chinese Journal of Rock Mechanics and Engineering,2020,39(10):2148 − 2159. (in Chinese with English abstract) LIU Kuan, YE Wanjun, GAO Haijun, et al. Multi-scale effects of mechanical property degradation of expansive soils under drying-wetting environments[J]. Chinese Journal of Rock Mechanics and Engineering, 2020, 39(10): 2148-2159. (in Chinese with English abstract) |
[23] | 程龙虎, 聂如松, 刘飞. 裂隙性黄土单轴抗压试验研究[J]. 水文地质工程地质,2017,44(5):80 − 85. [CHENG Longhu, NIE Rusong, LIU Fei. An experimental study of the uniaxial compressive strength of fractured loess[J]. Hydrogeology & Engineering Geology,2017,44(5):80 − 85. (in Chinese with English abstract) CHENG Longhu, NIE Rusong, LIU Fei. An experimental study of the uniaxial compressive strength of fractured loess[J]. Hydrogeology & Engineering Geology, 2017, 44(5): 80-85. (in Chinese with English abstract) |
[24] | 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) |
[25] | 中华人民共和国住房和城乡建设部. 膨胀土地区建筑技术规范: GB 50112—2013[S]. 北京: 中国建筑工业出版社, 2013 Ministry of Housing and Urban-Rural Development of the People’s Republic of China. Technical code for building in expansive soil regions: GB 50112—2013[S]. Beijing: China Architecture & Building Press, 2013. (in Chinese) |
[26] | 刘华强, 殷宗泽. 裂缝对膨胀土抗剪强度指标影响的试验研究[J]. 岩土力学,2010,31(3):727 − 731. [LIU Huaqiang, YIN Zongze. Test study of influence of crack evolution on strength parameters of expansive soil[J]. Rock and Soil Mechanics,2010,31(3):727 − 731. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-7598.2010.03.010 LIU Huaqiang, YIN Zongze. Test study of influence of crack evolution on strength parameters of expansive soil[J]. Rock and Soil Mechanics, 2010, 31(3): 727-731. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-7598.2010.03.010 |
Schematic diagram of the crack morphology
Schematic diagram of the test apparatus
Partial stress-strain curves of Cpe with specific width and depth
Schematic diagram of the key points of the stress-strain curve
Partial stress-strain curves of Cpa
Stress-strain curve model of the expansive soil with cracks
Quantitative index of the curve shape
Relationship between qu and crack direction and number
Relationship between εce and Ece of the Cpe samples and crack number