Email Alerts
RSS
Discriminating piping process in sandy gravels based on Reynolds number
-
摘要: 管涌破坏是发生堤坝险情乃至溃决的主要原因。传统渗流力学涉及管涌机理、发展过程及控制措施，对管涌过程定量判别及非线性特征研究尚显不足。开展不同级配砂砾石管涌试验，指出细颗粒含量及均匀程度是影响砂砾石管涌破坏的主要因素；分析管涌破坏过程中水流状态变化规律，提出了基于雷诺数Re的管涌过程判别方法。试验结果表明：砂砾石管涌过程可定量分为孕育阶段（Re<0.85）、形成阶段（0.85≤Re≤5.00）、发展阶段（5.00<Re≤50.00）和破坏阶段（Re>50.00）。孕育和形成阶段，可动细颗粒启动并缓慢调整，水力坡降与渗流速度呈线性关系，黏阻力占主控作用，渗流运动符合达西定律；发展和破坏阶段，渗流通道形成并逐步扩展，可动细颗粒快速流失，渗流速度变化较大，惯性力占主控作用，水力坡降与渗流速度呈远离平衡态的非线性关系，层流逐渐向紊流过渡，可用二次方程描述。研究结果可为管涌险情预报和应急处置提供决策依据。Abstract: Piping is one of the main reasons of dike and dam break in defective reservoirs. Traditional seepage theories focus on piping mechanism, developing process and controlling measures, yet seldom shed light on quantitative discrimination and nonlinear characteristics of overall piping process. Groups of laboratory tests of piping process in different grading sandy gravels were conducted, and the judging method of overall piping process was proposed by the analysis of fluid regime changes based on the Reynolds number, which shows that fines content and uniformity are main influence factors of piping failure. The whole process of piping in sandy gravels can be quantitatively divided into four stages, that is, incubation (Re<0.85), formation (0.85≤Re≤5.00), evolution (5.00<Re≤50.00) and destruction (Re>50.00). During incubation and formation stages, removable fine particles are started up and adjusted, and the relationship between hydraulic gradient and seepage velocity is linear. Viscous drag force plays an important role, and seepage flow conforms to the Darcy’s law. However, during evolution and destruction stages, seepage pathway is gradually formed and developed, and removable fine particles run off rapidly. Meanwhile, the seepage velocity changes increasingly, and the relationship between hydraulic gradient and seepage velocity is nonlinear, which shows the inertial force plays a leading role. Laminar flow gradually transfers into turbulent flow, which can be described by a quadratic equation. The research findings can provide the base for piping scientific forecast and emergency disposal.
-
Key words:
- piping process /
- judgement method /
- Reynolds number /
- hydraulic gradient /
- seepage velocity
-
图 2 天然砂砾石和室内配制砂砾石颗粒级配曲线
Figure 2. Grain-size distribution curves of natural sandy gravels and indoor artificial sandy gravels
图 3 土样C不同测点水力坡降随渗流速度变化曲线
Figure 3. Process curve between hydraulic gradient and seepage flow velocity of different parts in soil number C
图 4 土样C不同测点渗透系数随水力坡降变化曲线
Figure 4. Process curve between hydraulic gradient and permeability of different parts in soil number C
图 5 土样C测压管渗压水位过程线
Figure 5. Process curve of water head of different piezometers located in soil number C
图 6 土样1不同测点水力坡降随渗流速度变化曲线
Figure 6. Process curve between hydraulic gradient and seepage flow velocity of different parts in soil number 1
图 7 土样1不同测点渗透系数随水力坡降变化曲线
Figure 7. Process curve between hydraulic gradient and permeability of different parts in soil number 1
图 8 土样1测压管渗压水位过程线
Figure 8. Process curve of water head of different piezometers located in soil number 1
图 9 土样2不同测点水力坡降随渗流速度变化曲线
Figure 9. Process curve between hydraulic gradient and seepage flow velocity of different parts in soil number 2
图 10 土样2不同测点渗透系数随水力坡降变化曲线
Figure 10. Process curve between hydraulic gradient and permeability of different parts in soil number 2
图 11 土样2测压管渗压水位过程线
Figure 11. Process curve of water head of different piezometers located in soil number 2
表 1 试验土样物理力学参数
Table 1. Physical and mechanical parameters of experimental soils
试样 编号 不均匀
系数d50/
mm孔隙率 干密度/
(g·cm−3)渗透系数/
(cm·s−1)试样 编号 不均匀
系数d50/
mm孔隙率 干密度/
(g·cm−3)渗透系数/
(cm·s−1)天然
土样A 81.25 20.00 0.26 1.96 3.35×10−2 人工
土样1 58.80 10.00 0.24 2.02 3.35×10−2 B 150.00 16.00 0.29 1.89 3.20×10−2 2 78.30 14.00 0.21 2.17 4.00×10−3 C 73.30 12.00 0.22 2.08 1.10×10−2 3 35.00 10.20 0.22 2.04 2.39×10−3 D 66.70 20.00 0.24 2.02 1.02×10−2 4 80.00 7.00 0.20 1.93 6.55×10−3 E 45.70 11.00 0.27 1.94 1.10×10−2 
下载: 导出CSV
表 2 管涌过程坡降及时间变化
Table 2. Gradient and time changes of piping process
试样 编号 临界坡降 破坏坡降 连通时间/min 破坏时间/h 试样 编号 临界坡降 破坏坡降 连通时间/min 破坏时间/h 天然
砂砾石A 0.23 0.29 35 5.5 人
工
砂
砾
石1 0.22 0.46 40 6.5 B 0.44 0.51 38 6.0 2 0.43 0.58 25 6.0 C 0.39 0.48 30 5.0 3 0.46 0.60 30 6.5 D 0.22 0.32 32 6.5 4 0.48 0.63 30 6.0 E 0.36 0.45 36 7.0
下载: 导出CSV
表 3 不同细粒含量下砂砾石渗透破坏过程对比结果
Table 3. Comparative results of sandy gravels seepage failure process under different fine particle contents
试样 粒径小于2 mm细粒质量分数/% 渗透系数/(cm·s−1) 临界坡降 破坏坡降 连通时间/min 1 18 3.35×10−2 0.22 0.46 40 C 23 1.10×10−2 0.39 0.48 30 2 25 4.00×10−3 0.43 0.58 25
下载: 导出CSV
-
[1] 陆一忠, 陈生水, 米占宽. 防汛抢险训练场渗透破坏段设计方案试验分析[J]. 水利水运工程学报,2015(2):67-72 LU Yizhong, CHEN Shengshui, MI Zhankuan. Design analysis of a seepage failure segment for the flood control training field of Jiangsu Province[J]. Hydro-Science and Engineering, 2015(2): 67-72. (in Chinese) [2] 王宇, 王士军, 谷艳昌. 基于分形理论的多孔介质渗透破坏研究[J]. 中国农村水利水电,2016(3):80-83, 87 doi: 10.3969/j.issn.1007-2284.2016.03.019 WANG Yu, WANG Shijun, GU Yanchang. Research on seepage failure in porous media based on fractal theory[J]. China Rural Water and Hydropower, 2016(3): 80-83, 87. (in Chinese) doi: 10.3969/j.issn.1007-2284.2016.03.019 [3] WANG Y, WANG S J, DUAN X B, et al. Physical modelling of initial seepage failure process[J]. International Journal of Physical Modelling in Geotechnics, 2015, 15(4): 220-228. doi: 10.1680/jphmg.14.00049 [4] 蒋中明, 王为, 冯树荣, 等. 应力状态下含黏粗粒土渗透变形特性试验研究[J]. 岩土工程学报,2014,36(1):98-104 doi: 10.11779/CJGE201401008 JIANG Zhongming, WANG Wei, FENG Shurong, et al. Experimental study on influence of stress state on seepage failure characteristics of coarse grained soil with cohesive particles[J]. Chinese Journal of Geotechnical Engineering, 2014, 36(1): 98-104. (in Chinese) doi: 10.11779/CJGE201401008 [5] 王宇, 谷艳昌, 王士军, 等. 基于多孔介质土体分形特征的渗透系数研究[J]. 水利水运工程学报,2022(3):50-58 doi: 10.12170/20210629001 WANG Yu, GU Yanchang, WANG Shijun, et al. Permeability coefficient investigation based on fractal characteristics of porous media soil[J]. Hydro-Science and Engineering, 2022(3): 50-58. (in Chinese) doi: 10.12170/20210629001 [6] 姚志雄, 周健, 张刚. 砂土管涌机理的细观试验研究[J]. 岩土力学,2009,30(6):1604-1610 doi: 10.3969/j.issn.1000-7598.2009.06.012 YAO Zhixiong, ZHOU Jian, ZHANG Gang. Meso-experimental research on piping mechanism in sandy soils[J]. Rock and Soil Mechanics, 2009, 30(6): 1604-1610. (in Chinese) doi: 10.3969/j.issn.1000-7598.2009.06.012 [7] 陈建生, 何文政, 王霜, 等. 双层堤基管涌破坏过程中上覆层渗透破坏发生发展的试验与分析[J]. 岩土工程学报,2013,35(10):1777-1783 CHEN Jiansheng, HE Wenzheng, WANG Shuang, et al. Laboratory tests on development of seepage failure of overlying layer during piping of two-stratum dike foundation[J]. Chinese Journal of Geotechnical Engineering, 2013, 35(10): 1777-1783. (in Chinese) [8] 介玉新, 董唯杰, 傅旭东, 等. 管涌发展的时间过程模拟[J]. 岩土工程学报,2011,33(2):215-219 JIE Yuxin, DONG Weijie, FU Xudong, et al. Modelling of developing course of piping with time[J]. Chinese Journal of Geotechnical Engineering, 2011, 33(2): 215-219. (in Chinese) [9] 罗玉龙, 速宝玉, 盛金昌, 等. 对管涌机理的新认识[J]. 岩土工程学报,2011,33(12):1895-1902 LUO Yulong, SU Baoyu, SHENG Jinchang, et al. New understandings on piping mechanism[J]. Chinese Journal of Geotechnical Engineering, 2011, 33(12): 1895-1902. (in Chinese) [10] FORCHHEIMER P. Wasserbewegung durch boden[J]. Zeitschrift des Vereins Deutscherlngenieure, 1901, 1(45): 1782-1788. [11] IZBASH S V. Ofiltracii V kropnozemstom materiale[R]. Leningrad: USSR(in Russian), 1931: 1-23. [12] 万军伟, 黄琨, 陈崇希. 达西定律成立吗[J]. 地球科学,2013,38(6):1327-1330 WAN Junwei, HUANG Kun, CHEN Chongxi. Reassessing Darcy’ law on water flow in porous media[J]. Earth Science, 2013, 38(6): 1327-1330. (in Chinese) [13] 毛昶熙. 渗流计算分析与控制[M]. 2版. 北京: 中国水利水电出版社, 2003. MAO Changxi. Seepage computation analysis & control[M]. 2nd ed. Beijing: China Water & Power Press, 2003. （in Chinese） [14] 毛昶熙, 段祥宝. 关于“论土骨架与渗透力”的讨论[J]. 岩土工程学报,2017,39(2):385-386 doi: 10.11779/CJGE201702025 MAO Changxi, DUAN Xiangbao. Discussion on “On soil skeleton and seepage force”[J]. Chinese Journal of Geotechnical Engineering, 2017, 39(2): 385-386. (in Chinese) doi: 10.11779/CJGE201702025 [15] 丁洲祥. 一维渗透力与浮力[J]. 力学学报,2017,49(5):1154-1162 doi: 10.6052/0459-1879-17-001 DING Zhouxiang. One-dimensional seepage force and buoyancy[J]. Chinese Journal of Theoretical and Applied Mechanics, 2017, 49(5): 1154-1162. (in Chinese) doi: 10.6052/0459-1879-17-001 [16] 沙金煊. 预测堤防背侧管涌的一种方法[J]. 水利水运工程学报,2003(4):57-59 doi: 10.3969/j.issn.1009-640X.2003.04.012 SHA Jinxuan. A prediction method for piping in the back slope of levee[J]. Hydro-Science and Engineering, 2003(4): 57-59. (in Chinese) doi: 10.3969/j.issn.1009-640X.2003.04.012 [17] 吴迪, 周顺华, 李尧臣. 饱和砂土中泥浆渗透的变形-渗流-扩散耦合计算模型[J]. 力学学报,2015,47(6):1026-1036 doi: 10.6052/0459-1879-15-011 WU Di, ZHOU Shunhua, LI Yaochen. A deformation-infiltration-dispersion coupling model for the slurry infiltration computation in saturated sand[J]. Chinese Journal of Theoretical and Applied Mechanics, 2015, 47(6): 1026-1036. (in Chinese) doi: 10.6052/0459-1879-15-011 [18] 张健, 翟剑峰, 王仙美, 等. 基于球状井非稳定井流理论的管涌流场分布研究[J]. 水利水运工程学报,2014(1):49-55 doi: 10.3969/j.issn.1009-640X.2014.01.007 ZHANG Jian, ZHAI Jianfeng, WANG Xianmei, et al. Analysis of piping field distributions based on unsteady spherical well flow theory[J]. Hydro-Science and Engineering, 2014(1): 49-55. (in Chinese) doi: 10.3969/j.issn.1009-640X.2014.01.007 -
点击查看大图
计量
- 文章访问数: 201
- HTML全文浏览量: 78
- PDF下载量: 20
- 被引次数: 0
