Study on safety of a high earth-core rockfill dam considering contact effect between dam and foundation
-
摘要: 传统的土石坝结构计算分析中通常忽略坝体与基岩之间的摩擦滑动变形, 这与实际情况不符,坝体-地基接触摩擦效应对于修建在狭窄陡峻河谷区的特高坝表现尤为明显。采用三维有限元方法对修建在狭窄河谷区特高心墙堆石坝结构安全性进行了研究,研究中考虑了坝体-地基摩擦接触效应,模拟了水库蓄水、坝料湿化、流变等多因素共同作用下坝体结构力学行为以及坝体-地基接触位移演化过程。基于倾度法对坝体运行过程中可能的裂缝扩展区域进行了预测。研究得出:对于狭窄河谷上特高土石坝,坝体与地基的相对滑移较大,计算中应予以考虑。研究结论可为峡谷区特高心墙堆石坝设计提供技术依据。Abstract: With a traditional method to calculate the stress and deformation of earth-rock dam, the contact effect between the dam and the bedrock is neglected, which is not consistent with the actual condition. The contact friction has a significant effect on the high dams located in the narrow and steep valleys. In this research, a high earth-core rockfill dam to be built in a narrow valley area is studied, the friction contact effect between the dam and the bedrock, water storage, wetting and rheology effect are all considered to simulate the dam body behaviors. Based on the deformation gradient method, the area where cracks may occur during the operation of the dam is predicted. Calculation results are used to evaluate the safety of the earth-core rockfill dam. It is found that the relative slip displacement between dam body and foundation is large for high earth-rock dams in narrow river valleies and should be considered. The conclusion of the study can provide technical basis for the design and construction of high earth-core rockfill dams located in canyon areas.
-
表 1 如美筑坝料邓肯E-B模型参数
Table 1. Parameters of the E-B model of the Rumei dam materials
材料分区 ρ/(g·cm-3) 非线性强度 K n Rf Kb m φ0/° Δφ/° 堆石Ⅰ 2.170 55.8 10.30 1 066.0 0.413 0.70 936.0 0.066 堆石Ⅱ 2.107 54.2 9.70 975.0 0.400 0.72 724.3 0.075 过渡料 2.115 53.7 9.10 796.0 0.440 0.68 561.8 0.162 反滤Ⅰ料 1.957 55.7 10.10 1 016.8 0.425 0.68 936.3 0.070 反滤Ⅱ料 2.103 52.3 8.00 705.0 0.485 0.70 411.8 0.239 砾质土料 2.220 44.7 8.25 400.0 0.580 0.87 208.0 0.407 接触黏土 1.970 31.9 5.07 126.0 0.681 0.79 67.2 0.400 表 2 筑坝料流变模型参数
Table 2. Parameters of the creep model of the Rumei dam materials
坝体分区 流变模型参数 湿化模型参数 α b/% c/% d/% m1 m2 m3 cw/% nw Bw/% 堆石Ⅰ 0.001 0.120 0.022 0.313 0.396 0.542 0.794 0.066 0.62 0.359 堆石Ⅱ 0.001 0.129 0.026 0.364 0.405 0.540 0.817 0.072 0.628 0.419 砾质土料 0.001 0.309 0.055 0.607 0.339 0.479 0.790 0.274 0.307 0.533 表 3 大坝应力变形特征值
Table 3. Extreme values of the dam stress and deformation
统计时间 顺河向位移/cm 沉降/cm 沉降率/% 大主应力/MPa 小主应力/MPa 指向上游 指向下游 竣工期 26.9 33.1 284.3 0.90 4.65 1.65 初次蓄水 27.9 73.6 307.9 0.98 4.79 1.92 运行8年后 28.4 82.4 317.3 1.00 4.81 1.93 -
[1] 顾淦臣, 束一鸣, 沈长松.土石坝工程经验与创新[M].北京:中国电力出版社, 2004. GU Ganchen, SHU Yiming, SHEN Changsong. Experience and innovation of earth and rock dam engineering[M]. Beijing: China Electric Power Press, 2004. (in Chinese) [2] KULHAWY F H, DUNCAN J M. Stresses and movements in Oroville dam[J]. Journal of the Soil Mechanics and Foundations Division, 1972, 98(7): 653-665. http://cn.bing.com/academic/profile?id=900e6be402d44762273a26b5c518d4eb&encoded=0&v=paper_preview&mkt=zh-cn [3] WU Y K, ZHANG B Y, YU Y Z, et al. Consolidation analysis of Nuozhadu high earth-rockfill dam based on the coupling of seepage and stress-deformation physical state[J]. International Journal of Geomechanics, 2015, 16(3): 1-11. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=0da64008c7f04df583aacfefcbd5c332 [4] SKERMER N A. Mica dam embankment stress analysis[J]. Journal of the Geotechnical Engineering Division, 1975, 101: 229-242. http://cn.bing.com/academic/profile?id=11d491a83945dd09a6c061160a5eb32c&encoded=0&v=paper_preview&mkt=zh-cn [5] 张启岳, 熊国文.鲁布革坝的原型观测(一)[J].水利水运科学研究, 1994(3): 211-230. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK199400427129 ZHANG Qiyue, XIONG Guowen. Prototype observation of Lubuge dam Ⅰ[J]. Journal of Nanjing flydraulic Research Institute, 1994(3): 211-230. (in Chinese) http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK199400427129 [6] 宋文晶, 高莲士.窄陡河谷面板堆石坝坝肩摩擦接触问题研究[J].水利学报, 2005, 36(7): 793-798. http://d.old.wanfangdata.com.cn/Periodical/slxb200507005 SONG Wenjing, GAO Lianshi. Influence of valley topography on the safety of CFRD anti-seepage systems[J]. Journal of Hydroelectric Engineering, 2008, 27(4): 94-100. (in Chinese)) http://d.old.wanfangdata.com.cn/Periodical/slxb200507005 [7] 魏匡民, 陈生水, 李国英, 等.陡峻河谷高面板坝坝体与坝基接触效应[J].岩土力学, 2018, 39(9): 3415-3424. http://d.old.wanfangdata.com.cn/Periodical/ytlx201809036 WEI Kuangmin, CHEN Shengshui, LI Guoying, et al. Influence of contact effect between dam body and dam foundation on behaviors of high CFRDs built in steep valleys[J]. Rock and Soil Mechanics, 2018, 39(9): 3415-3424. (in Chinese) http://d.old.wanfangdata.com.cn/Periodical/ytlx201809036 [8] 李文轩, 卞士海, 李国英, 等.粗粒料接触面模型及其在土石坝工程中的应用[J].岩土力学, 2019, 40(6): 2379-2388. http://d.old.wanfangdata.com.cn/Periodical/ytlx201906037 LI Wenxuan, BIAN Shihai, LI Guoying, et al. Interface model of coarse-grained soils and its application in earth rock dam[J]. Rock and Soil Mechanics, 2019, 40(6): 2379-2388. (in Chinese) http://d.old.wanfangdata.com.cn/Periodical/ytlx201906037 [9] MAURICE A B. General theory of three-dimensional consolidation[J]. Journal of Applied Physics, 1941, 12(2): 155-164. doi: 10.1063/1.1712886 [10] 李国英, 米占宽, 傅华, 等.混凝土面板堆石坝堆石料流变特性试验研究[J].岩土力学, 2004, 25(11): 1712-1716. doi: 10.3969/j.issn.1000-7598.2004.11.007 LI Guoying, MI Zhankuan, FU Hua, et al. Experimental studies on rheological behaviors for rockfills in concrete faced rockfill dam[J]. Rock and Soil Mechanics, 2004, 25(11): 1712-1716. (in Chinese) doi: 10.3969/j.issn.1000-7598.2004.11.007 [11] 殷宗泽.土工原理[M].北京:中国水利水电出版社, 2007. YIN Zongze. Principles of geotechnical engineering[M]. Beijing: China Water Resources and Hydropower Press, 2007. (in Chinese) [12] CLOUGH G W, DUNCAN J M. Finite element analyses of retaining wall behavior[J]. Journal of the Soil Mechanics and Foundations Division, 1971, 97(SM12): 1657-1672. http://cn.bing.com/academic/profile?id=ab9cad158e0f7ff8ee8ea16cedf2db25&encoded=0&v=paper_preview&mkt=zh-cn [13] 林道通, 朱晟, 邬铭科, 等.瀑布沟砾石土心墙堆石坝初次蓄水期坝顶裂缝成因分析[J].水力发电, 2017, 43(10): 56-61. http://d.old.wanfangdata.com.cn/Periodical/slfd201710015 LIN Daotong, ZHU Sheng, WU Mingke, et al. Cause analysis of crest cracking of Pubugou rockfill dam with a central gravelly soil core during first reservoir impounding[J]. Water Power, 2017, 43(10): 56-61. (in Chinese) http://d.old.wanfangdata.com.cn/Periodical/slfd201710015 [14] 韩朝军, 朱晟.土质防渗土石坝坝顶裂缝开裂机理与成因分析[J].中国农村水利水电, 2013(8): 116-120. doi: 10.3969/j.issn.1007-2284.2013.08.030 HAN Chaojun, ZHU Sheng. Cracking mechanism and cause analysis in earth-rock dam[J]. China Rural Water and Hydropower, 2013(8): 116-120. (in Chinese) doi: 10.3969/j.issn.1007-2284.2013.08.030 [15] 李君纯.土坝裂缝的简捷估算方法[J].水利水运科学研究, 1983(3): 1-11. http://www.cnki.com.cn/Article/CJFDTotal-SLSY198303000.htm LI Junchun. Simple calculation method of soil dam crack[J]. Journal of Nanjing Hydraulic Research Institute, 1983(3): 1-11. (in Chinese) http://www.cnki.com.cn/Article/CJFDTotal-SLSY198303000.htm [16] 张丙印, 张美聪, 孙逊.土石坝横向裂缝的土工离心机模型试验研究[J].岩土力学, 2008, 29(5): 1254-1258. doi: 10.3969/j.issn.1000-7598.2008.05.020 ZHANG Bingyin, ZHANG Meicong, SUN Xun. Centrifugal modeling of transverse cracking in earth core dams[J]. Rock and Soil Mechanics, 2008, 29(5): 1254-1258. (in Chinese) doi: 10.3969/j.issn.1000-7598.2008.05.020 -