Experimental study on mechanics and permeability characteristics of Jurassic red sandstone under hydro-mechanical coupling
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摘要:
三峡库区广泛分布侏罗系红砂岩, 在水库运行期间红砂岩的渗流-应力耦合特性关乎库区内多数滑坡和岩质边坡的稳定性。借助岩石多场耦合三轴试验系统, 对三峡库区侏罗系红砂岩开展了不同围压、不同渗透压下的三轴压缩试验, 系统研究了红砂岩的三轴压缩力学特性和渗透率演化特征。研究结果表明: ①红砂岩的峰前应力-应变曲线可分为孔隙压密阶段、弹性变形阶段、微裂隙稳定发展阶段和非稳定发展阶段。红砂岩的力学参数与渗透压的关系呈负相关, 与围压呈正相关。②随着围压升高, 红砂岩的破坏模式由张拉破坏过渡到剪切破坏。③不同渗透压下, 渗透率曲线呈平稳发展→缓慢上升→快速上升3阶段演化规律; 不同围压下, 渗透率曲线先降低后升高。④从能量角度分析了渗透压和围压对岩石的作用, 验证了渗流对岩石的劣化效应以及围压对裂纹发展的抑制作用。本试验对鲜有报道的侏罗系红砂岩的强度、变形和渗透特性做了系统的研究, 对渗流-应力耦合课题有补充意义。其工况根据三峡库区边坡岩体的应力水平来确定, 试验结果对分析库区边坡稳定性具有指导意义。
Abstract:Jurassic red sandstone is widely distributed in the Three Gorges reservoir area. During the operation of the red sandstone reservoir, the hydro-mechanical coupling characteristics affect the stability of most landslides and rock slopes. In this paper, triaxial compression tests under different confining pressures and osmotic pressures are carried out on the Jurassic red sandstone in the Three Gorges Reservoir area by means of the multi-field coupled triaxial test system. The mechanical properties and permeability evolution characteristics of the red sandstone under triaxial compression are systematically studied. The results show that: ①The pre-peak stress-strain curve of red sandstone can be divided into pore compaction stage, elastic deformation stage, stable development stage of micro-cracks, and unsteady development stage. The mechanical parameters of red sandstone are negatively correlated with osmotic pressure and positively correlated with confining pressure. ②With the increasing of confining pressure, the failure mode of red sandstone transitions from tensile failure to shear failure.③The permeability under different osmotic pressures shows a "three-stage" evolution law of developing steadily firstly, then increasing slowly and increasing sharply lastly; the permeability under different confining pressures decreases firstly and then increases. ④The effects of osmotic pressure and confining pressure on rock are analyzed from the perspective of energy, and the degradation effect of seepage inrock and the inhibition effect of confining pressure on crack development are verified. The experimental results have guiding significance for the stability of bank slope.In this experiment, the strength, deformation and permeability characteristics of the little-reported Jurassic red sandstone were systematically studied, which is of complementary significance to the topic of seepage-stress coupling. The working conditions are determined according to the stress level of the rock mass on the slope of the Three Gorges reservoir area, and the test results have guiding significance for analyzing the stability of the slope in the reservoir area.
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图 8 渗透压、偏应力与轴应变关系曲线
a.围压3 MPa, 渗透压1 MPa; b.围压3 MPa, 渗透压1.5 MPa; c.围压3 MPa, 渗透压2 MPa; d.围压5 MPa, 渗透压2 MPa; e.围压7 MPa, 渗透压2 MPa
Figure 8. Osmotic pressure, deviatoric stress-axial strain curves
图 9 不同渗透压下红砂岩能量变化曲线
a.渗透压1 MPa, 围压3 MPa; b.渗透压1.5 MPa，围压3 MPa; c.渗透压2 MPa，围压3 MPa; d.能量大小
Figure 9. Energy evolution curves under various osmotic pressure
图 10 不同围压下红砂岩能量变化曲线
a.围压3 MPa，渗透压2 MPa; b.围压5 MPa，渗透压2 MPa; c.围压7 MPa，渗透压2 MPa; d.能量大小
Figure 10. Energy evolution curves under various confining pressure
表 1 红砂岩基本物理参数
Table 1. Physical properties of red sandstone
试样编号 直径/mm 长度/mm 天然密度/(g·cm-3) 孔隙率/% 饱和吸水率/% 压缩波波速/(m·s-1) 1# 49.36 101.89 2.643 1.62 0.66 3 453.79 2# 49.52 102.15 2.649 1.49 0.56 3 462.42 3# 49.38 101.96 2.651 1.52 0.62 3 455.87 4# 49.41 101.64 2.643 1.65 0.63 3 444.83 5# 49.67 101.43 2.651 1.47 0.56 3 447.59 
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表 2 试验方案
Table 2. Experimental scheme
试样编号 围压/MPa 渗透压/MPa 1# 3 1.0 2# 3 1.5 3# 3 2.0 4# 5 2.0 5# 7 2.0
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表 3 红砂岩试样特征应力
Table 3. Characteristic intensity of red sandstone
试样编号 闭合应力/MPa 起裂应力/MPa 损伤应力/MPa 1# 18.96% 53.24% 72.36% 2# 13.97% 34.08% 80.66% 3# 14.11% 33.87% 71.24% 4# 16.36% 38.63% 82.22% 5# 12.18% 54.55% 79.60%
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表 4 红砂岩力学参数
Table 4. Mechanical parameters of red sandstone
试样编号 围压/MPa 渗透压/MPa 峰值应力/MPa 初始弹性模量/GPa 泊松比 最大体积应变/% 1# 3.0 1.0 127.90 24.4 0.345 0.124 6 2# 3.0 1.5 121.50 21.1 0.326 0.140 4 3# 3.0 2.0 119.95 13.5 0.304 0.157 3 4# 5.0 2.0 125.27 20.1 0.364 0.091 7 5# 7.0 2.0 137.13 21.4 0.451 0.017 0
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表 5 红砂岩初始渗透率
Table 5. Initial permeability of red sandstone
岩样编号 初始渗透率/10-19 m2 1# 2.5 2# 5.1 3# 8.0 4# 1.3 5# 0.8
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[1] 赵阳升. 多孔介质多场耦合作用及其工程响应[M]. 北京: 科学出版社, 2010.Zhao Y S. Multi field coupling and its engineering response of porous media[M]. Beijing: Science Press, 2010(in Chinese). [2] Wu A Q, Fan L, Fu X, et al. Design and application of hydro-mechanical coupling test system for simulating rock masses in high dam reservoir operations[J/OL]. International Journal of Rock Mechanics and Mining Sciences, 2021, 140. [2021-07-10]. http://doi.org/10.1016/j.ijrmms.2021-104638. [3] 张怡悦, 殷坤龙, 陈丽霞, 等. 奉节县曾家棚滑坡时空差异性变形特征与成因机制分析[J]. 地质科技通报, 2020, 39(2): 148-157. doi: 10.19509/j.cnki.dzkq.2020.0216Zhang Y Y, Yin K L, Chen L X, et al. Characteristics and mechanism of spatio-temporal difference deformation of Zengijiapeng landslide[J]. Bulletin of Geological Science and Technology, 2020, 39(2): 148-157(in Chinese with English abstract). doi: 10.19509/j.cnki.dzkq.2020.0216 [4] 李长冬, 龙晶晶, 姜茜慧, 等. 水库滑坡成因机制研究进展与展望[J]. 地质科技通报, 2020, 39(1): 67-77. doi: 10.19509/j.cnki.dzkq.2020.0108Li C D, Long J J, Jiang X H, et al. Advance and prospect of formation mechanism for reservoir landslides[J]. Bulletin of Geological Science and Technology, 2020, 39(1): 67-77(in Chinese with English abstract). doi: 10.19509/j.cnki.dzkq.2020.0108 [5] 侯伟, 仵彦卿, 丁卫华. 裂隙岩体渗流场与应力场耦合研究进展与展望[J]. 山西建筑, 2006, 32(15): 1-2. https://www.cnki.com.cn/Article/CJFDTOTAL-JZSX200615000.htmHou W, Wu Y Q, Ding W H. Advances and future research directions in the models of coupled seepage and stress fields in fractured rock mass[J]. Shanxi Architecyure, 2006, 32(15): 1-2(in Chinese). https://www.cnki.com.cn/Article/CJFDTOTAL-JZSX200615000.htm [6] 刘仲秋, 章青. 岩体中饱和渗流应力耦合模型研究进展[J]. 力学进展, 2008, 38(5): 585-600. https://www.cnki.com.cn/Article/CJFDTOTAL-LXJZ200805006.htmLiu Z Q, Zhang Q. A review on the stage of art of the satura seepage-stress coupling models in rock mass[J]. Advances in Mechanics, 2008, 38(5): 585-600(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-LXJZ200805006.htm [7] Kou M M, Liu X R, Wang Z Q, et al. Laboratory investigations on failure, energy and permeability evolution of fissured rock-like materials under seepage pressures[J/OL]. Engineering Fracture Mechanics, 2021. (2021-4-15)[2021-7-10]. http://doi.org/10.1016/j.engfracmech.2021.107694. [8] Meng Z P, Li G Q, Xie X T. A geological assessment method of floor water inrush risk and its application[J]. Engineering Geology, 2012, 143: 51-60. [9] Tan X, Heinz K, Thomas F. Laboratory observation and numerical simulation of permeability evolution during progressive failure of brittle rocks[J]. International Journal of Rock Mechanics and Mining Sciences, 2014, 68: 167-176. doi: 10.1016/j.ijrmms.2014.02.016 [10] Heiland J. Laboratory testing of coupled hydro-mechanical processes during rock deformation[J]. Hydrogeology Journal, 2003, 11(1): 122-141. doi: 10.1007/s10040-002-0236-2 [11] Mitchell T M, Faulkner D R. Experimental measurements of permeability evolution during triaxial compression of initially intact crystalline rocks and implications for fluid flow in fault zones[J]. Journal of Geophysical Research, 2008, 113(B11): B11412-1-B11412-16-0. [12] Wang S, Elsworth D, Liu J. Permeability evolution during progressive deformation of intact coal and implications for instability in underground coal seams[J]. International Journal of Rock Mechanics and Mining Sciences, 2013, 58: 34-45. doi: 10.1016/j.ijrmms.2012.09.005 [13] Tao M, Yechao Y, Jie C, et al. Investigation on the permeability evolution of gypsum interlayer under high temperature and triaxial pressure[J/OL]. Rock Mechanics and Rock Engineering, 2017, 50(8): 2059-2069. [14] Xiao W J, Zhang D M, Wang X J. Experimental study on progressive failure process and permeability characteristics of red sandstone under seepage pressure[J/OL]. Engineering Geology, 2020: 265. [2021-7-10]. https://doi.org/10.1016/j.enggeo.2019.105406. [15] 张金才, 张玉卓. 应力对裂隙岩体渗流影响的研究[J]. 岩土工程学报, 1998, 20(2): 19-22. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC802.005.htmZhang J C, Zhang Y Z. The efects of stresses on the permeability of fractured rock masses[J]. Chinese Journal of Geotechnical Engineering, 1998, 20(2): 19-22(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC802.005.htm [16] Chen Y, Hu S, Wei K, et al. Experimental characterization and micromechanical modeling of damage-induced permeability variation in Beishan granite[J]. International Journal of Rock Mechanics and Mining Sciences, 2014, 71: 64-76. [17] 胡少华, 陈益峰, 周创兵. 北山花岗岩渗透特性试验研究与细观力学分析[J]. 岩石力学与工程学报, 2014, 33(11): 2200-2209. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201411005.htmHu S H, Chen Y F, Zhou C B. Laboratory test and mesomechanical analysis of permeability variation of beishan granite[J]. Chinese Journal of Rock Mechanics and Engineering, 2014, 33(11): 2200-2209(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201411005.htm [18] 王传乐, 李二兵, 韩阳, 等. 三轴压缩条件下北山花岗岩的力学特性及破裂演化[J]. 林业工程学报, 2018, 3(4): 151-158. https://www.cnki.com.cn/Article/CJFDTOTAL-LKKF201804026.htmWang C L, Li E B, Han Y, et al. Study on mechanical characteristics and fracture evolution of Beishan granite undertriaxial compression[J]. Journal of Forestry Engineering, 2018, 3(4): 151-158(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-LKKF201804026.htm [19] 俞缙, 李宏, 陈旭, 等. 渗透压-应力耦合作用下砂岩渗透率与变形关联性三轴试验研究[J]. 岩石力学与工程学报, 2013, 32(6): 1203-1213. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201306015.htmYu J, Li H, Chen X, et al. Triaxial experimental study of associated permeability-deformation of sandstone under hydro-mechanical coupling[J]. Chinese Journal of Rock Mechanics and Engineering, 2013, 32(6): 1203-1213(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201306015.htm [20] 边光. 真三轴加卸载条件下砂岩力学特性及渗流规律试验研究[D]. 重庆: 重庆大学, 2017.Bian G. Experimental study on mechanical properties and gas permeability of sandstone under true triaxial loadling and unloading[D]. Chongqing: Chongqing University, 2017(in Chinese with English abstract). [21] 李燕, 杨林德, 董志良, 等. 各向异性软岩的变形与渗流耦合特性试验研究[J]. 岩土力学, 2009, 30(5): 1231-1236. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX200905007.htmLi Y, Yang L D, Dong Z L, et al. Experimental research on characteristic of deformation and hydromechanical couplingof anistropic rock[J]. Rock and Soil Mechanics, 2009, 30(5): 1231-1236(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX200905007.htm [22] 李宏国, 朱大勇, 姚华彦, 等. 温度作用后大理岩加-卸荷破裂特性试验研究[J]. 合肥工业大学学报: 自然科学版, 2016, 39(1): 109-114. https://www.cnki.com.cn/Article/CJFDTOTAL-HEFE201601022.htmLi H G, Zhu D Y, Yao H Y, et al. Loading and unloading test on fracture characteristics of marble after heating[J]. Journal of Hefei University of Technology, 2016, 39(1): 109-114(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-HEFE201601022.htm [23] 王向刚. 脆性材料中三维裂隙破坏过程试验与数值模拟研究[D]. 济南: 山东大学, 2014.Wang X G. The study on experiment and numericsimulation of fracture progress of flaws in brittle materials[D]. Jinan: Shandong University, 2014(in Chinese with English abstract). [24] 张培森, 侯季群, 赵成业, 等. 不同围压不同损伤程度红砂岩渗流特性试验研究[J]. 岩石力学与工程学报, 2020, 39(12): 2405-2415. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX202012003.htmZhang P S, Hou J Q, Zhao Y C, et al. Experimental study on seepage characteristics of red sandstone with differentconfining pressures and different damage degrees[J]. Chinese Journal of Rock Mechanics and Engineering, 2020, 39(12): 2405-2415(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX202012003.htm [25] 王志俭, 殷坤龙, 简文星, 等. 三峡库区万州红层砂岩流变特性试验研究[J]. 岩石力学与工程学报, 2008, 27(4): 840-847. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX200804028.htmWang Z J, Yin K L, Jian W X, et al. Experimental study on rheological behaviors of Wanzhou red sandstone in Three Gorges Reservoir Area[J]. Chinese Journal of Rock Mechanics and Engineering, 2008, 27(4): 840-847(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX200804028.htm [26] 柴波, 殷坤龙, 简文星, 等. 红层水岩作用特征及库岸失稳过程分析[J]. 中南大学学报: 自然科学版, 2009, 40(4): 1092-1098. https://www.cnki.com.cn/Article/CJFDTOTAL-ZNGD200904043.htmCai B, Yin K L, Jian W X, et al. Analysis of water-rock interaction characteristics and bank slope failure process of red-bed[J]. Journal of Central South University: Science and Technology, 2009, 40(4): 1092-1098(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-ZNGD200904043.htm [27] 陈小川. 三峡水库运行期消落带红砂岩强度劣化的化学干预研究[D]. 合肥: 合肥工业大学, 2019.Chen X C. Study on chemical intervention for strength degradation of red sandstone in drawdown area during the course of Three Gorges reservoir operation[D]. Hefei: Hefei University of Technology, 2019(in Chinese with English abstract). [28] 胡新丽, David M P, Lidija Z, 等. 三峡水库运行条件下金乐滑坡稳定性评价[J]. 地球科学: 中国地质大学学报, 2007, 32(3): 403-408. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200703013.htmHu X L, David M P, Lidija Z, et al. Jinle landslide stability under water level fluctuation of Three Gorges Reservoir[J]. Earth Science: Journal of China University of Geosciences, 2007, 32(3): 403-408(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200703013.htm [29] Wang Q, Hu X, Xu C, et al. Time-dependent behavior of saturated silty mudstone under different confining pressures[J]. Bulletin of Engineering Geology and the Environment, 2020, 79(5): 2621-2634. [30] Martin C D, Chandler N A. The progressive fracture of lac du bonnet granite[J]. International Journal of Rock Mechanics and Ming Sciences & Geomechanics Abstracts, 1994, 31(6): 643-659. [31] Alam A K M B, Niioka M, Fujii Y, et al. Effects ofconfining pressure on the permeability of three rock types under compression[J]. International Journal of Rock Mechanics and Mining Sciences, 2014, 65: 49-61. -
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