Fracture failure mechanism and fracture criterion of compacted clay under compression and shear action
-
摘要: 土体既有裂缝的开裂问题通常被认为是拉剪应力导致,而实际工程中压实黏土多处于压剪应力状态,为探究压剪作用下压实黏土中既有裂缝的起裂机理,对压剪闭合裂缝应力场和断裂准则进行了理论分析,开展了含中心裂缝压实黏土单轴压缩试验,研究了裂缝倾角、裂缝长度及裂缝形态对压剪断裂性状的影响,揭示了压实黏土中闭合裂缝压剪张拉断裂机理,充分验证了闭合裂缝压剪张拉断裂准则在压实黏土中的适用性。根据试验结果与理论预测曲线对比分析,本文压实黏土的临界尺寸rc为2 mm左右,明显小于常用经验公式估算值12 mm,讨论了rc经验估算公式存在的问题。此外,尝试性地引入T应力,建立了非闭合裂缝的压剪-张拉断裂准则,解释了闭合裂缝和非闭合裂缝的差异化起裂行为,并说明了其局限性及其产生原因。Abstract: Soil cracks are often considered to be caused by tensile-shear stress. In actual engineering, the compacted clay is mostly under compressive-shear stress state. In order to explore the crack initiation mechanism of the existing cracks in the compacted clay under compressive-shear stress state, the stress field and fracture criterion of the closed crack are analyzed theoretically. The uniaxial compression tests on the compacted clay with central cracks are carried out. The influence of dip angle, length and shape of cracks on the tensile fracture behavior of the compacted clay are investigated. The applicability of the compression-shear closed-crack tension fracture criterion considering T-stress in the compacted clay is verified, and the compression-shear tension fracture mechanism of closed cracks in the compacted clay is revealed. According to the comparative analysis of the test results and the theoretical prediction curve, the critical size rc of the compacted clay is about 2 mm, which is obviously smaller than the estimated value of 12 mm by the empirical formula used in the rock field. Through detailed discussion, it is shown that the formula applied in the rock field is not suitable for the compacted clay. In addition, the T-stress is introduced tentatively to establish a compression-shear-tension fracture criterion for open cracks. The differential initiation behavior of closed and open cracks is explained, and its limitations are shown.
-
Keywords:
- compressive shear stress /
- closed crack /
- fracture criterion /
- compacted clay /
- T-stress
-
-
![]()
图 1 裂缝尖端应力场及裂缝起裂方向定义
Figure 1. Stress field at crack tip and definition of crack initiation direction
![]()
图 2 双向压缩作用下中心斜裂缝的应力场
Figure 2. Stress field of inclined crack under biaxial compression
![]()
图 4 单向受压时裂缝面受力状态
Figure 4. Stress distribution on crack surface under uniaxial compression
![]()
图 5 裂缝倾角对闭合裂缝起裂特征的影响（2a/W = 0.5）
Figure 5. Effects of β on initiation characteristics of closed cracks
![]()
图 6 裂缝长度对闭合裂缝起裂特征的影响（β = 45°）
Figure 6. Effects of 2a on initiation characteristics of closed cracks
![]()
图 9 裂缝长度对闭合裂缝试样峰值应力和起裂应力的影响
Figure 9. Effects of crack length on peak stress and initiation stress of closed crack samples
![]()
图 10 裂缝倾角对含裂缝试样峰值应力的影响
Figure 10. Effects of angles on peak stress of fracture samples
![]()
图 11 裂缝倾角对含裂缝试样起裂应力的影响
Figure 11. Effects of angles on initiation stress of fracture samples
![]()
图 12 α对裂缝尖端最大周向应力的影响（μ = 0.38）
Figure 12. Effects of α on maximum tangential stress of crack tip
![]()
图 13 不同应力状态下α对起裂角的影响
Figure 13. Effects of α oninitiation angle under different stress states
![]()
图 14 非闭合裂缝和光滑闭合裂缝的张拉起裂角
Figure 14. Initiation angles of open cracks and smoothly closed cracks
表 1 试验土料强度特性
Table 1 Strength properties of test clay
KIC/(kPa·m0.5) σt /kPa c/kPa φ/(°) 17 62 68 22 
下载: 导出CSV
表 2 试验方案
Table 2 Test schemes
类型 裂缝倾角β/(°) 无量纲裂缝长度2a/W 闭合 0,15,30,45,60,75 0.5 闭合 45 0.2,0.35,0.65 非闭合 15,30,45,60 0.5 注： W为试样的边长,100 mm。
下载: 导出CSV
-
[1] 张丙印, 温彦锋, 朱本珍. 土工构筑物和边坡工程发展综述——作用机理与数值模拟方法[J]. 土木工程学报, 2016, 49(8): 1-15. https://www.cnki.com.cn/Article/CJFDTOTAL-TMGC201608001.htm ZHANG Bing-yin, WEN Yan-feng, ZHU Ben-zhen, et al. Development review of geotechnical structures and slope engineering-action mechanism and numerical simulation method[J]. Chinese Journal of Civil Engineering, 2016, 49(8): 1-15. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-TMGC201608001.htm
[2] 吉恩跃, 陈生水, 傅中志. 土心墙堆石坝坝顶裂缝扩展有限元模拟[J]. 岩土工程学报, 2018, 40(增刊2): 17-21. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC2018S2006.htm JI En-yue, CHEN Sheng-shui, FU Zhong-zhi. Numerical simulation of crest cracks in an earth core rockfill dam using extended finite element method[J]. Chinese Journal of Geotechnical Engineering, 2018, 40(S2): 17-21. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC2018S2006.htm
[3] 凌华, 王伟, 王芳. 砾石土心墙料水力劈裂试验研究[J]. 岩土工程学报, 2018, 40(8): 1444-1448. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201808011.htm LING Hua, WANG Wei, WANG Fang. Experimental study on hydraulic fracture of gravelly soil core[J]. Chinese Journal of Geotechnical Engineering, 2018, 40(8): 1444-1448. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201808011.htm
[4] CAMP S, GOURC J P, PLE O. Landfill clay barrier subjected to cracking: multi-scale analysis of bending tests[J]. Applied Clay Science, 2010, 48(3): 384-392. doi: 10.1016/j.clay.2010.01.011
[5] SKEMPTON A W, SCHUSTER R L, PETLEY D J, et al. Joints and fissures in the london clay at wraysbury and edgware[J]. Géotechnique, 1970, 20: 208-209. doi: 10.1680/geot.1970.20.2.208
[6] THUSYANTHAN N I, TAKE W A, MADABHUSHI S P G, et al. Crack initiation in clay observed in beam bending[J]. Géotechnique, 2007, 57(7): 581-594. doi: 10.1680/geot.2007.57.7.581
[7] WANG J J, ZHU J G, CHIU C F, et al. Experimental study on fracture toughness and tensile strength of a clay[J]. Engineering Geology, 2007, 94(1/2): 65-75.
[8] RAO Q, SUN Z, STEPHANSSON O, et al. Shear fracture (Mode II) of brittle rock[J]. International Journal of Rock Mechanics and Mining Sciences, 2003, 40(3): 355-375. doi: 10.1016/S1365-1609(03)00003-0
[9] JI W, PAN P, LIN Q, et al. Do disk-type specimens generate a mode II fracture without confinement?[J]. International Journal of Rock Mechanics and Mining Sciences, 2016, 87: 48-54. doi: 10.1016/j.ijrmms.2016.05.010
[10] LIN H, YANG H T, WANG Y X, et al. Determination of the stress field and crack initiation angle of an open flaw tip under uniaxial compression[J]. Theoretical and Applied Fracture Mechanics, 2019, 104: 102358. doi: 10.1016/j.tafmec.2019.102358
[11] 郑安兴, 罗先启. 压剪应力状态下岩石复合型断裂判据的研究[J]. 岩土力学, 2015(7): 1892-1898. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201507014.htm ZHENG An-xing, LUO Xian-qi. Research on combined fracture criterion of rock under compression-shear stress[J]. Rock and Soil Mechanics, 2015(7): 1892-1898. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201507014.htm
[12] 高赛红, 曹平, 汪胜莲. 水压力作用下岩石中Ⅰ和Ⅱ型裂纹断裂准则[J]. 中南大学学报(自然科学版), 2012, 43(3): 1087-1091. https://www.cnki.com.cn/Article/CJFDTOTAL-ZNGD201203046.htm GAO Sai-hong, CAO Ping, WANG Sheng-lian. Analysis of fracture criterion of Ⅰ and Ⅱ type of crack in rock masses under hydraulic pressure[J]. Journal of Central South University (Science and Technology), 2012, 43(3): 1087-1091. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-ZNGD201203046.htm
[13] ZHAO Y, WANG Y, TANG L. The compressive-shear fracture strength of rock containing water based on Druker-Prager failure criterion[J]. Arabian Journal of Geosciences, 2019, 12(15): 452. doi: 10.1007/s12517-019-4628-1
[14] 周家文, 徐卫亚, 石崇. 基于破坏准则的岩石压剪断裂判据研究[J]. 岩石力学与工程学报, 2007(6): 1194-1201. doi: 10.3321/j.issn:1000-6915.2007.06.014 ZHOU Jia-wen, XU Wei-ya, SHI Chong. Investigation on compression-shear fracture criterion of rock based on failure criteria[J]. Chinese Journal of Geotechnical Engineering, 2007(6): 1194-1201. (in Chinese) doi: 10.3321/j.issn:1000-6915.2007.06.014
[15] 李世愚, 和泰名, 尹祥础. 岩石断裂力学导论[M]. 合肥: 中国科学技术大学出版社, 2010. LI Shi-yu, HE Tai-ming, YIN Xiang-chu. Introduction of Rock Fracture Mechanics[M]. Hefei: University of Science and Technology of China Press, 2010.
[16] ZHANG X, WONG L N Y. Cracking processes in rock-like material containing a single flaw under uniaxial compression: a numerical study based on parallel bonded-particle model approach[J]. Rock Mechanics and Rock Engineering, 2012, 45(5): 711-737.
[17] SMITH D J, AYATOLLAHI M R, PAVIER M J. The role of T-stress in brittle fracture for linear elastic materials under mixed-mode loading[J]. Fatigue Fracture of Engineering Materials and Structures, 2001, 24(2): 137-150. doi: 10.1046/j.1460-2695.2001.00377.x
[18] LIU H. Wing-crack initiation angle: a new maximum tangential stress criterion by considering T-stress[J]. Engineering Fracture Mechanics, 2018, 199: 380-391. doi: 10.1016/j.engfracmech.2018.06.010
[19] 朱俊高, 王俊杰, 张辉. 土石坝心墙水力劈裂机制研究[J]. 岩土力学, 2007(3): 487-492. doi: 10.3969/j.issn.1000-7598.2007.03.011 ZHU Jun-gao, WANG Jun-jie, ZHANG Hui. Study on mechanism of hydraulic fracturing in core of earth-rockfill dam[J]. Rock and Soil Mechanics, 2007(3): 487-492. (in Chinese) doi: 10.3969/j.issn.1000-7598.2007.03.011
[20] 王俊杰. 基于断裂力学的土石坝心墙水力劈裂研究[D]. 南京: 河海大学, 2005. WANG Jun-jie. Study on Hydraulic Fracturing in Core of Earth-Rock Fill Dam Based on Fracture Mechanics[D]. Nanjing: Hohai University, 2005. (in Chinese)
[21] WILLIAMS J G, EWING P D. Fracture under complex stress —the angled crack problem[J]. International Journal of Fracture Mechanics, 1972, 8(4): 441-446. doi: 10.1007/BF00191106
[22] ALIHA M R M, AYATOLLAHI M R. Two-parameter fracture analysis of SCB rock specimen under mixed mode loading[J]. Engineering Fracture Mechanics, 2013, 103: 115-123. doi: 10.1016/j.engfracmech.2012.09.021
[23] TANG S B, BAO C Y, LIU H Y. Brittle fracture of rock under combined tensile and compressive loading conditions[J]. Canadian Geotechnical Journal, 2017, 54(1): 88-101. doi: 10.1139/cgj-2016-0214
[24] SCHMIDT R. A microcrack model and its significance to hydraulic fracturing and fracture toughness testing[J]. US Symposium on Rock Mechanics, 1980, 18(5): 581-590.
[25] AYATOLLAHI M R, ALIHA M R M. On the use of Brazilian disc specimen for calculating mixed mode I-II fracture toughness of rock materials[J]. Engineering Fracture Mechanics, 2008, 75(16): 4631-4641. doi: 10.1016/j.engfracmech.2008.06.018
[26] 赵彦琳, 范勇, 朱哲明, 等. T应力对闭合裂纹断裂行为的理论和实验研究[J]. 岩石力学与工程学报, 2018, 37(6): 1340-1349. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201806003.htm ZHAO Yan-lin, FAN Yong, ZHU Ze-ming, et al. Analytical and experimental study on the effect of T-stress on behavior of closed cracks[J]. Chinese Journal of Rock Mechanics and Engineering, 2018, 37(6): 1340-1349. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201806003.htm
[27] WANG J J, HUANG S Y, GUO W L, et al. Experimental study on fracture toughness of a compacted clay using semi-circular bend specimen[J]. Engineering Fracture Mechanics, 2020, 224: 106814. doi: 10.1016/j.engfracmech.2019.106814
[28] 蒲成志, 杨仕教, 张春阳. 张开度影响的裂隙体破断机制探讨[J]. 岩土工程学报, 2019(10): 1836-1844. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201910009.htm PU Cheng-zhi, YANG Shi-jiao, ZHANG Chun-yang. Fracture mechanism of fracture body affected by opening degree[J]. Chinese Journal of Geotechnical Engineering, 2019(10): 1836-1844. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201910009.htm
[29] 郭少华. 岩石类材料压缩断裂的实验与理论研究[D]. 长沙: 中南大学, 2003. GUO Shao-hua. The Experimental and Theoretical Investigation on Fracture of Rock-Type Materials under Compressive Loading[D]. Changsha: Central South University, 2003. (in Chinese)
[30] MUSKHELISHVILI N. Some Basic Problems of the Mathematical Theory of Elasticity[M]. Leyden: Noordhoff, 1953.
[31] HUA W, DONG S, FAN Y, et al. Investigation on the correlation of mode II fracture toughness of sandstone with tensile strength[J]. Engineering Fracture Mechanics, 2017, 184: 249-258. doi: 10.1016/j.engfracmech.2017.09.009
[32] BOBET A. The initiation of secondary cracks in compression[J]. Engineering Fracture Mechanics, 2000, 66(2): 187-219. doi: 10.1016/S0013-7944(00)00009-6
-
期刊类型引用(3)
1. 范文晓. 南阳膨胀土浸水变形特性及微观结构研究. 建筑科学. 2025(01): 126-135 . 
百度学术
2. 李从安，许晓彤，沈登乐，王卫，胡波. 弱膨胀土三轴膨胀模型及其应用. 长江科学院院报. 2023(10): 137-141 . 百度学术
3. 叶云雪，邹维列，韩仲，谢鹏，张俊峰，徐永福. 考虑初始状态影响的膨胀土一维膨胀特性研究. 岩土工程学报. 2021(08): 1518-1525 . 本站查看
其他类型引用(3)
计量
- 文章访问数:
- HTML全文浏览量: 0
- PDF下载量:
- 被引次数: 6
