35 2 2016 6 GLOBAL GEOLOGY Vol. 35 No. 2 Jun. 2016 1004 5589 2016 02 0559 08 130026 GeoStudio 2007 TV139. 16 TV543. 8 A doi 10. 3969 /j. issn. 1004-5589. 2016. 02. 029 Large-sized physical model of two-dimensional dam seepage field LI Peng-fei XU Pei-hua HAN Jing L Jin-zhi College of Construction Engineering Jilin University Changchun 130026 China Abstract Experiments were conducted in large scale sand tank to simulate the two-dimensional seepage process through large sand grain in dam foundation to analyze the variations of the seepage situation. Soil samples in different location were taken out to analyze their particles composition after seepage failure. Based on the parameters obtained from the experiments numerical analysis is conducted to simulate the seepage field using the software of GeoStudio 2007 whose results of the spatial distribution of the seepage field agreed well with those from experiments indicating the reasonable of the experimental model. Results showed that seepage deformation mainly occurred in dam foundation where the seepage path was short while there were no clear deformation along the upstream and downstream of the dam foundation. The seepage path changed greatly after seepage failure leading to the great increase of the volume of seepage flow thus accelerating the damage process. Key words seepage filed sand tank dam foundation seepage deformation 0 241 1000 31. 7% 1 52% 2 2015-09-03 2016-01-20 41302218. 1979 -. E-mail xuph@ jlu. edu. cn
560 35 3 4-6 1 mm Fig. 1 Model design 80 m 100 1 m 100 m 7 8 1. 2 9 1. 2. 1 2 C u = 49. 51 C c = 10. 17 C u C c 11 1 1. 1 1. 8 m 0. 3 m 0. 5 m 1 30 cm 30 cm 12 20 kpa 70 cm 30 cm 20 15cm 9 1 / 2 2 10 50 cm Fig. 2 Testing particles analysis curve 40 cm 80 cm 10 cm
2 561 2 cm 1 R e 0. 01 31 cm 2 R = A /χ 12 h R e 119 71 89 < 500 1 k h 3 = 0. 661 m h 4 1 = 0. 995 m h = h 4 - h 3 = 0. 334 m Table 1 Pressure before and after piping erosion 13 k 1 = QL /Fh = 1. 713 10-4 m 3 /s 1 ~ 1 1 ~ 2 2 ~ 1 2 ~ 2 2 ~ 3 k 2 = QL /Fh = 2. 138 10-4 m 3 /s /cm 21. 1 30. 5 22. 1 36. 2 55. 9 /cm 21. 5 30. 5 23. 2 35. 1 40. 2 3 ~ 1 3 ~ 2 3 ~ 3 3 ~ 4 4 ~ 1 /cm 30. 2 70. 5 81. 5 82. 5 127. 1 /cm 26. 1 48. 5 65. 1 61. 2 71. 1 4 ~ 2 4 ~ 3 4 ~ 4 5 ~ 1 5 ~ 2 /cm 92. 2 95. 5 83. 5 140. 2 130 /cm 72. 5 78. 3 72. 3 125. 2 115. 1 5 ~ 3 5 ~ 4 6 ~ 1 6 ~ 2 6 ~ 3 / cm 120 115 120 118 110 /cm 105. 5 100. 2 140. 1 120. 2 110. 3 1. 2. 2 1. 86 10-4 m 3 3. 5 2. 5 /s 2. 0 1. 5 0. 5 R e = vr v 1 v v = A χ k = k 1 + k 2 /2 = 1. 926 10-4 m 3 /s 4. 35 10-4 m 3 /s 3 30 cm 30 cm 10 cm Fig. 3 3 Comparison chart of permeate outlet downstream of dam before and after piping erosion
562 35 R e 5 R e 276 166 145 < 500 70 cm 30 cm 10 cm 2 Table 2 2 Permeability coefficient of different region /10-4 m 3 s - 1 1 2 3 4 5 K 1. 97 1. 03 9. 00 8. 15 7. 76 3. 19 2. 41 6 6 d 10 0. 2 mm 0. 18 mm d 10 3 30 cm d 10 30 cm Table 3 Particle size of cumulation weight to 10% after 1. 3 seepage failure /cm 0 ~ 10 10 ~ 20 20 ~ 30 30 ~ 40 40 ~ 50 d 4 10 /mm 1. 3 0. 5 0. 24 0. 19 0. 19 3 10% Fig. 4 4 Simulation dam surface soil samples before and after infiltration and sabotage < 0. 5 mm 4 5 mm 18. 14% Table 4 Percentage of particles less than 5 mm in different layers after seepage failure 19. 07% /cm 0 ~ 10 10 ~ 20 20 ~ 30 30 ~ 40 40 ~ 50 4 30 cm < 30 cm < 0. 5 mm 2 30 cm 80 cm < 1 /2 /% 7. 17 10. 07 12. 75 17. 35 17. 42 GeoStudio2007SEEP /W
第2 期 李鹏飞 徐佩华等 坝基二维渗流场的大尺寸物理模型试验 563 a. 10 cm b. 20 cm c. 30 cm d. 40 cm 图5 Fig. 5 渗透破坏后不同层位的照片 Pictures of different layer particles after seepage failure 验测得 2. 1 数值模型的建立 数值模型范围为 1. 8 m 0. 5 m 0. 3 m 长 深 宽 网 格 剖 分 后 包 含 节 点 457 个 单 元 418 个 单元格 0. 047 5 m 0. 047 5 m 图 7 试验开始时试验槽内为均匀砂样 所以材料为 同一属性 只将材料划为一个大区 管涌后试验槽 发生不均匀破坏根据物理模型试验结果 将渗透 破坏后的模型槽分为三个区 坝上游区 模拟坝基 区和坝下游区 其中模拟坝基区从上至下又分为 5 个区 图 7 由 于 所 取 砂 样 不 均 匀 系 数 达 到 了 49 很容易形成管涌 坝上游加到 2 m 水头就产生 图6 Fig. 6 原状样和试验后各部分颗分曲线 Particles analysis curve of initial and each part after test particles 了管涌 故边界条件为坝上游区表面 2 m 水头 坝 下游区表面 0. 12 m 水头 2. 2 数值模拟结果分析 图 8 和图 9 为渗透破坏前后的渗流矢量图 两
564 35 Fig. 7 7 8 Mesh dissection of numerical model and calculation Fig. 8 Seepage vector of initial physical model division Fig. 9 9 10 Seepage vector after seepage failure Fig. 10 Seepage path and equipotential line of initial physical model 3. 33 10-4 m /s 9 25 cm 30 cm 10 10 11 11 Fig. 11 Seepage path and equlipotential line of after seepage failure 3. 742 10-4 m /s 4. 35 10-4 m /s 3 1 GeoStudio 2007 2 10 11 1. 161 2 10-4 m /s 1. 86 10-4 m /s
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