Influence of particle loss on the seepage characteristics of tuff in the fault fracture zone under triaxial stress
-
摘要: 地下工程施工过程中,处于三向应力状态的断层破碎带凝灰岩在流固耦合作用下发生颗粒流失,继而诱发断层带破碎岩石结构失稳,最终导致断层突水灾害发生。基于此,开展现场断层取样,利用破碎岩石三轴渗透试验系统,研究三轴荷载下不同粒径级配试样颗粒流失规律,进而分析颗粒流失对孔隙结构与渗流流速时变演化规律的影响。研究结果表明:(1)不同三轴应力下,破碎凝灰岩颗粒流失质量与时间满足指数型函数关系,两者间相关系数不低于94%。颗粒流失质量与轴压和围压成反比,且轴向位移越大,颗粒流失质量随围压减小的幅度越小;(2)渗透过程中0~60 s间的孔隙率增长较快,孔隙结构的渗流演变过程与粒径级配有关,随着n (Talbot幂指数) 值的增大,孔隙率整体增大,n值相同时,孔隙率随轴向位移与围压的增大而减小,且孔隙率量级为0.33~0.52;(3)由于试样内部颗粒规律性流失,破碎凝灰岩渗流流速时变演化过程可划分为“平稳渗流、渗流流速突增和近似管流”三个阶段,围压为0.8 MPa时各阶段流速整体大于围压为1.4 MPa时对应阶段的流速。平稳渗流阶段历时短,流速低,其发生次数随n值增加而减少;渗流流速突增阶段流速猛增达到峰值;近似管流阶段保持较高流速,虽然偶尔产生波动,但整体相对平稳。研究成果可为断层突水灾害演化规律研究提供理论依据。Abstract: In the process of underground engineering construction, tuff in the fault fracture zone under a three-dimensional stress state loses particles under the action of fluid–solid coupling, causing the structural instability of the fault fracture rock. Finally, fault water inrush disaster occurs. Based on this, the field fault sampling has been conducted, and the broken rock triaxial seepage test system has been used to investigate the phenomenon of particle loss in samples with various particle sizes under triaxial load, as well as the effect of particle loss on pore structure and the time-varying evolution of seepage velocity. The following are the results: (1) The quality and time of the particle loss of broken tuff satisfy the exponential nonlinear relationship under different levels of triaxial stress, with a correlation coefficient of not less than 94%. Particle loss quality is inversely related to axial pressure and confining pressure, indicating that the higher the axial displacement, the smaller the decrease in particle loss mass with confining pressure. (2) The porosity increases rapidly between 0 and 60 s during the infiltration process. The seepage evolution process of the pore structure is related to the particle size gradation; that is, the overall porosity increases as the value of n (Talbot power exponent) increases. In the case of the same value of n, the porosity, which ranges from 0.33 to 0.52, decreases as the axial displacement and confining pressure increase. (3) Owing to the regular loss of particles in the sample, the time-varying evolution process of the seepage velocity of fractured tuff can be divided into three stages: stable seepage, sudden increase of seepage velocity, and approximate pipe flow. When the confining pressure is 0.8 MPa, each stage’s flow velocity is higher than that of the corresponding stage when the confining pressure is 1.4 MPa. The stable seepage stage has a short duration and low flow rate, and its occurrence times decrease as the n value increases. In the stage of seepage velocity surge, velocity surges to a peak value. The approximate pipe flow stage maintains a relatively stable and high flow velocity despite occasional fluctuations. The research results can offer a theoretical basis for studying the evolution law of fault water inrush disaster.
-
Key words:
- shattered fault zone /
- tuff /
- triaxial stress /
- particle loss /
- pore structure
-
图 7 不同围压下流失颗粒质量−时间拟合曲线. (a) 轴向位移为3 mm,围压为0.8 MPa; (b) 轴向位移为3 mm,围压为1.4 MPa; (c) 轴向位移为6 mm,围压为0.8 MPa; (d) 轴向位移为6 mm,围压为1.4 MPa
Figure 7. Lost particles mass–time fitting curve under different confining pressures: (a) axial displacement is 3 mm, confining pressure is 0.8 MPa; (b) axial displacement is 3 mm, confining pressure is 1.4 MPa; (c) axial displacement is 6 mm, confining pressure is 0.8 MPa; (d) axial displacement is 6 mm, confining pressure is 1.4 MPa
图 13 不同n值级配试样渗透试验中流速−时间试验结果(图中AD指轴向位移, CP指围压). (a) n=0.2; (b) n=0.4; (c) n=0.6; (d) n=0.8
Figure 13. Flow velocity–time test results of different Talbot power exponent gradation samples in penetration test (AD means axial displacement, CP means confining pressure): (a) n=0.2; (b) n=0.4; (c) n=0.6; (d) n=0.8
表 1 不同Talbot幂指数n值下的岩石颗粒质量
Table 1. Rock particle mass under different n
Rock grain size/mm Particle mass/g n=0.2 n=0.4 n=0.6 n=0.8 0−0.25 114.76 54.88 26.24 12.55 0.25−0.5 17.07 17.53 13.53 9.30 0.5−1 19.60 23.14 20.52 16.19 1−2 22.52 30.52 31.09 28.19 2−5 34.98 55.82 66.96 71.61 5−10 31.07 58.11 81.66 102.16 -
参考文献
[1] Li S C, Xu Z H, Huang X, et al. Classification, geological identification, hazard mode and typical case studies of hazard-causing structures for water and mud inrush in tunnels. Chin J Rock Mech Eng, 2018, 37(5): 1041李术才, 许振浩, 黄鑫, 等. 隧道突水突泥致灾构造分类、地质判识、孕灾模式与典型案例分析. 岩石力学与工程学报, 2018, 37(5):1041 [2] Li X Z, Zhang P X, He Z C, et al. Identification of geological structure which induced heavy water and mud inrush in tunnel excavation: A case study on Lingjiao tunnel. Tunn Undergr Space Technol, 2017, 69: 203 doi: 10.1016/j.tust.2017.06.014 [3] Li S C, Chen Z Q, Miao X X, et al. Experimental study on the properties of time-dependent deformation-seepage in water-saturated broken sandstone. J Mini Saf Eng, 2011, 28(4): 542 doi: 10.3969/j.issn.1673-3363.2011.04.008李顺才, 陈占清, 缪协兴, 等. 饱和破碎砂岩随时间变形−渗流特性试验研究. 采矿与安全工程学报, 2011, 28(4):542 doi: 10.3969/j.issn.1673-3363.2011.04.008 [4] Miu X X, Liu W Q, Chen Z Q. Seepage Theory of Mining Rock Mass. Beijing: Science Press, 2004缪协兴, 刘卫群, 陈占清. 采动岩体渗流理论. 北京: 科学出版社, 2004 [5] Chen Z Q, Li S C, Mao X B, et al. Experimental on the porosity changing of water-saturated granular limestone during its creep. J China Coal Soc, 2006, 31(1): 26 doi: 10.3321/j.issn:0253-9993.2006.01.006陈占清, 李顺才, 茅献彪, 等. 饱和含水石灰岩散体蠕变过程中孔隙度变化规律的试验. 煤炭学报, 2006, 31(1):26 doi: 10.3321/j.issn:0253-9993.2006.01.006 [6] Sun M G, Huang X W, Li T Z, et al. Seepage properties of non-Darcy flow in complete failure process of limestone. Chin J Rock Mech Eng, 2006, 25(3): 484 doi: 10.3321/j.issn:1000-6915.2006.03.008孙明贵, 黄先伍, 李天珍, 等. 石灰岩应力−应变全过程的非Darcy流渗透特性. 岩石力学与工程学报, 2006, 25(3):484 doi: 10.3321/j.issn:1000-6915.2006.03.008 [7] Wang W, Xu W Y, Wang R B, et al. Permeability of dense rock under triaxial compression. Chin J Rock Mech Eng, 2015, 34(1): 40王伟, 徐卫亚, 王如宾, 等. 低渗透岩石三轴压缩过程中的渗透性研究. 岩石力学与工程学报, 2015, 34(1):40 [8] Du F, Li Z H, Jiang G H, et al. Types and mechanism of water-sand inrush disaster in west coal mine. J China Coal Soc, 2017, 42(7): 1846杜锋, 李振华, 姜广辉, 等. 西部矿区突水溃沙类型及机理研究. 煤炭学报, 2017, 42(7):1846 [9] Yao B H. Research on Variable on Variable Mass Fluid-Solid Coupling Dynamic Theory of Broken Rockmass and Application [Dissertation]. Xuzhou: China University of Mining and Technology, 2012姚邦华. 破碎岩体变质量流固耦合动力学理论及应用研究[学位论文]. 徐州: 中国矿业大学, 2012 [10] Liu W Q, Fei X D, Fang J N. Rules for confidence intervals of permeability coefficients for water flow in over-broken rock mass. Int J Min Sci Technol, 2012, 22(1): 29 doi: 10.1016/j.ijmst.2011.06.003 [11] Ma D, Miao X X, Chen Z Q, et al. Experimental investigation of seepage properties of fractured rocks under different confining pressures. Rock Mech Rock Eng, 2013, 46(5): 1135 [12] Ma D, Rezania M, Yu H S, et al. Variations of hydraulic properties of granular sandstones during water inrush: Effect of small particle migration. Eng Geol, 2017, 217: 61 doi: 10.1016/j.enggeo.2016.12.006 [13] Ma D, Duan H Y, Liu J F, et al. The role of gangue on the mitigation of mining-induced hazards and environmental pollution: An experimental investigation. Sci Total Environ, 2019, 664: 436 doi: 10.1016/j.scitotenv.2019.02.059 [14] Zhang T J, Shang H B, Li S G, et al. Permeability characteristics of broken sandstone and its stability analysis under step loading. J China Coal Soc, 2016, 41(5): 1129张天军, 尚宏波, 李树刚, 等. 分级加载下破碎砂岩渗透特性试验及其稳定性分析. 煤炭学报, 2016, 41(5):1129 [15] Zhang T J, Shang H B, Li S G, et al. Permeability tests of fractured sandstone with different sizes of fragments under three-dimensional stress states. Rock Soil Mech, 2018, 39(7): 2361张天军, 尚宏波, 李树刚, 等. 三轴应力下不同粒径破碎砂岩渗透特性试验. 岩土力学, 2018, 39(7):2361 [16] Zhang T J, Zhang X F, Pang M K, et al. Effect of particle loss on the pore structure and emergent behavior of karst column fills. J China Coal Soc, 2021, 46(10): 3245张天军, 张秀锋, 庞明坤, 等. 颗粒流失对陷落柱充填物孔隙结构及突水行为的影响. 煤炭学报, 2021, 46(10):3245 [17] Zhang B Y, Bai H B, Zhang K. Experimental research on seepage mutation mechanism of collapse column medium. Rock Soil Mechs, 2016, 37(3): 745张勃阳, 白海波, 张凯. 类陷落柱介质渗流突变机制试验研究. 岩土力学, 2016, 37(3):745 [18] Zhang B Y, Lin Z B, Wu J Y, et al. Seepage characteristics of broken rock inside collapse column under application of lateral limited uniaxial compression. J Min Saf Eng, 2020, 37(5): 1045张勃阳, 林志斌, 吴疆宇, 等. 侧限条件下陷落柱破碎岩体的渗流特性研究. 采矿与安全工程学报, 2020, 37(5):1045 [19] Feng M M, Wu J Y, Ma D, et al. Experimental investigation on the seepage property of saturated broken red sandstone of continuous gradation. Bull Eng Geol Environ, 2018, 77(3): 1167 doi: 10.1007/s10064-017-1046-z [20] Yang B, Xu Z H, Yang T H, et al. Experimental study of non-linear water flow through unconsolidated porous media under condition of high hydraulic gradient. Rock Soil Mech, 2018, 39(11): 4017杨斌, 徐曾和, 杨天鸿, 等. 高水力梯度条件下颗粒堆积型多孔介质渗流规律试验研究. 岩土力学, 2018, 39(11):4017 [21] Yu B Y, Chen Z Q, Yu L L. Water-resisting ability of cemented broken rocks. Int J Min Sci Technol, 2016, 26(3): 449 doi: 10.1016/j.ijmst.2016.02.013 [22] Liu W T, Du Y H, Yu S J, et al. Research on permeability and acoustic emission characteristics of karst collapsed column skeleton sandstone under triaxial compression. Chin J Rock Mech Eng, 2021, 40(8): 1580刘伟韬, 杜衍辉, 于师建, 等. 陷落柱骨架砂岩三轴压缩渗流特性及声发射特征试验研究. 岩石力学与工程学报, 2021, 40(8):1580 [23] Wasantha P L P, Ranjith P G. Water-weakening behavior of Hawkesbury sandstone in brittle regime. Eng Geol, 2014, 178: 91 doi: 10.1016/j.enggeo.2014.05.015 [24] Zhao J H, Yin L M, Guo W J. Stress-seepage coupling of cataclastic rock masses based on digital image technologies. Rock Mech Rock Eng, 2018, 51(8): 2355 doi: 10.1007/s00603-018-1474-5 [25] Li Y S, Yang Y J, Yang S Q, et al. Deformation and acoustic emission behaviors of coal under triaxial compression and pore water pressure. J Univ Sci Technol Beijing, 2011, 33(6): 658李玉寿, 杨永杰, 杨圣奇, 等. 三轴及孔隙水作用下煤的变形和声发射特性. 北京科技大学学报, 2011, 33(6):658 [26] Yan B Q, Ren F H, Cai M F, et al. Research review of rock mechanics experiment and numerical simulation under THMC multi-field coupling. Chin J Eng, 2021, 43(1): 47颜丙乾, 任奋华, 蔡美峰, 等. THMC多场耦合作用下岩石力学实验与数值模拟研究进展. 工程科学学报, 2021, 43(1):47 [27] Li S C, Miao X X, Chen Z Q, et al. Experimental study on seepage properties of non-Darcy flow in confined broken rocks. Eng Mech, 2008, 25(4): 85李顺才, 缪协兴, 陈占清, 等. 承压破碎岩石非Darcy渗流的渗透特性试验研究. 工程力学, 2008, 25(4):85 [28] Ma D, Duan H Y, Zhang J X, et al. Experimental investigation of creep-erosion coupling mechanical properties of water inrush hazards in fault fracture rock masses. Chin J Rock Mech Eng, 2021, 40(9): 1751马丹, 段宏宇, 张吉雄, 等. 断层破碎带岩体突水灾害的蠕变−冲蚀耦合力学特性试验研究. 岩石力学与工程学报, 2021, 40(9):1751 [29] Wu J Y, Han G S, Feng M M, et al. Mass-loss effects on the flow behavior in broken argillaceous red sandstone with different particle-size distributions. Comptes Rendus Mécanique, 2019, 347(6): 504 [30] Feng M M, Wu J Y, Chen Z Q, et al. Experimental study on the compaction of saturated broken rock of continuous gradation. J China Coal Soc, 2016, 41(9): 2195冯梅梅, 吴疆宇, 陈占清, 等. 连续级配饱和破碎岩石压实特性试验研究. 煤炭学报, 2016, 41(9):2195 [31] Xie H P, Gao F, Zhou H W, et al. Fractal fracture and fragmentation in rocks. J Disas Prev Mitig Eng, 2003, 23(4): 1谢和平, 高峰, 周宏伟, 等. 岩石断裂和破碎的分形研究. 防灾减灾工程学报, 2003, 23(4):1 [32] Yu J, Lü X B, Qin Y J. Experimental study on concrete beams without web reinforcement based on fractal theory. Chin J Eng, 2021, 43(10): 1385于江, 吕旭滨, 秦拥军. 基于分形理论无腹筋混凝土梁的受剪性能. 工程科学学报, 2021, 43(10):1385 [33] Zhang G T, Chen Y, Lu H B, et al. Fractal characteristics of fiber lithium slag concrete cracks under sulfate attack. Chin J Eng, 2022, 44(2): 208张广泰, 陈勇, 鲁海波, 等. 硫酸盐侵蚀作用下纤维锂渣混凝土裂缝的分形特征. 工程科学学报, 2022, 44(2):208 [34] Zhu S, Wang Y M, Weng H Y. Study of scale effect of density of coarse-grained dam materials. Chin J Rock Mech Eng, 2011, 30(2): 348朱晟, 王永明, 翁厚洋. 粗粒筑坝材料密实度的缩尺效应研究. 岩石力学与工程学报, 2011, 30(2):348 [35] Yin S H, Chen X, Liu C, et al. Effects of ore size distribution on the pore structure characteristics of packed ore beds. Chin J Eng, 2020, 42(8): 972尹升华, 陈勋, 刘超, 等. 矿石颗粒级配对堆浸体系三维孔隙结构的影响. 工程科学学报, 2020, 42(8):972 [36] Xie D S, Cai H, Wei Y Q, et al. Scaling principle and method in seepage tests on coarse materials. Chin J Geotech Eng, 2015, 37(2): 369 doi: 10.11779/CJGE201502023谢定松, 蔡红, 魏迎奇, 等. 粗粒土渗透试验缩尺原则与方法探讨. 岩土工程学报, 2015, 37(2):369 doi: 10.11779/CJGE201502023 [37] Wu J Y, Feng M M, Mao X B, et al. Particle size distribution of aggregate effects on mechanical and structural properties of cemented rockfill: Experiments and modeling. Constr Build Mater, 2018, 193: 295 doi: 10.1016/j.conbuildmat.2018.10.208 [38] Zhu G S, Zhang J F, Chen J S, et al. Study of size and wall effects in seepage test of broadly graded coarse materials. Rock Soil Mech, 2012, 33(9): 2569朱国胜, 张家发, 陈劲松, 等. 宽级配粗粒土渗透试验尺寸效应及边壁效应研究. 岩土力学, 2012, 33(9):2569 [39] Liu M S, Luo Q, Jiang L W, et al. Boundary pore characteristics and optimal treatment thickness in seepage test of coarse grained soil. Rock Soil Mech, 2019, 40(5): 1787刘孟适, 罗强, 蒋良潍, 等. 粗粒土渗透试验边壁孔隙特征及处理层最优厚度研究. 岩土力学, 2019, 40(5):1787 [40] Yu B Y, Chen Z Q, Wu J Y, et al. Experimental study of compaction and fractal properties of grain size distribution of saturated crushed mudstone with different gradations. Rock Soil Mech, 2016, 37(7): 1887郁邦永, 陈占清, 吴疆宇, 等. 饱和级配破碎泥岩压实与粒度分布分形特征试验研究. 岩土力学, 2016, 37(7):1887 -