Centrifugal model tests on connecting form between cutoff wall and composite geomembrane of cofferdam
LI Bo, CHENG Yong-hui, CHENG Zhan-lin
Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources, Changjiang River Scientific Research Institute, Wuhan 430010, China
Abstract：The connection effectiveness between cutoff wall and composite geomembrane of cofferdam, both of which are usually applied in the cofferdam, plays an important role in seepage control. Based on the site invitation of stage II cofferdam of Three Gorges Project, three centrifuge tests are performed in order to reveal the mechanism of the connecting form of cutoff wall and composite geomembrane by measuring the displacements of the cofferdam fillings and cutoff wall and the strain of the composite membrane. The friction between the composite geomembrane and the cofferdam fillings is so large that the expansion deformation reservation cannot work. Two main influencing factors include the settlement of the weathered sand foundation and the lateral displacement of cutoff wall, which both play a decisive function in the fracture of the composite geomembrane. Furthermore, an improved method of the connecting form, which make the composite geomembrane not be tensioned, is proposed and validated by centrifuge tests. The improved method provides a reliable evidence for the design and construction of the seepage control system of cofferdams.
李波, 程永辉, 程展林. 围堰防渗墙与复合土工膜联接型式离心模型试验研究[J]. 岩土工程学报, 2012, 34(11): 2081-2086.
LI Bo, CHENG Yong-hui, CHENG Zhan-lin. Centrifugal model tests on connecting form between cutoff wall and composite geomembrane of cofferdam. Chinese J. Geot. Eng., 2012, 34(11): 2081-2086.
[1] 顾淦臣. 复合土工膜或土工膜堤坝实例述评[J]. 水利水电技术, 2002, 33(12): 26-32 GU Gan-chen. Review of dams and dikes with composite geomembrane impervious structure[J]. Water Resources and Hydropower Engineering, 2002, 33(12): 26-32. (in Chinese)) [2] 岑威钧, 沈长松, 童建文. 深厚覆盖层上复合土工膜防渗堆石坝筑坝特性研究[J]. 岩土力学, 2009, 30(1): 175-180 CEN Wei-jun, SHEN Chang-song, DONG Jian-wen. Study of construction behavior of composite geomembrane ockfill dam on thick alluvium deposit[J]. Rock and Soil Mechanics, 2009, 30(1): 175-180. (in Chinese)) [3] 张自顺. 复合土工膜在景洪水电站二期围堰防渗中的应用[J]. 陕西水利, 2009(1): 97-98 ZHANG Zi-shun. Application of composite geomembrane in stage Ⅱ cofferdam anti-seepage of Jinhong Hydropower Station[J]. Shannxi Water Resources, 2009(1): 97-98. (in Chinese) ) [4] 张优秀, 徐 威, 王均星. 深溪沟水电站上游围堰渗流稳定计算结果分析[J]. 中国农村水利水电, 2011, 5: 169-171 ZHANG You-xiu, XU Wei, WANG Jun-xing. An analysis of calculation results for the seepage stability of the upstream cofferdam of the Shenxigou hydropower station[J]. China Rural Water and Hydropower, 2011, 5: 169-171. (in Chinese)) [5] 郑守仁, 陈珙新. 二期上下游横向围堰设计与实施验证[J]. 中国三峡建设, 1999, 5: 21-24 ZHEN Shou-ren, CHEN Gong-xin. Design, construction and operation of phase-II transverse cofferdam[J]. China Three Gorges Construction, 1999, 5: 21-24. (in Chinese)) [6] 李青云, 程展林. 三峡工程二期围堰运行后的性状分析[J]. 岩土工程学报, 2005, 27(4): 410-413 LI Qing-yun, CHENG Zhan-lin. Analysis of the behavior of stage II cofferdam of TGP[J]. Chinese Journal of Geotechnical Engineering, 2005, 27(4): 410-413. (in Chinese)) [7] 包承纲, 戴会超, 程展林, 等. 三峡工程深水高土石围堰的研究与实施[R]. 宜昌: 中国三峡开发总公司, 2002. BAO Cheng-gang, DAI Hui-chao, CHENG Zhan-lin,,et al. Research and Implementation of deep water high earth-rock cofferdam in Three Gorges project [R]. Yicang: China Three Gorges Corporation, 2002. [8] 包承纲. 土工合成材料应用原理与工程实践[M]. 中国水利水电出版社, 2008. BAO Cheng-gang. The principle and application of geosynthetics in engineering[M], China Water Power Press, 2008. (in Chinese)) [9] 程永辉, 李青云, 饶锡保, 等. 长江科学院土工离心机的应用与发展[J]. 长江科学院院报, 2011, 28(10): 141-147 CHENG Yong-hui, LI Qing-yun, RAO Xi-bao,,et al. Application and development of geotechnical centrifuge in Yangtze River Scientific Research Institute[J]. Journal of Yangtze River Scientific Research Institue, 2011, 28(10): 141-147. (in Chinese))
