荷载作用下高面膜堆石坝周边缝处坝体或坝肩的差异位移造成PVC膜处于大变形拉伸状态。为了探究差异位移稳定后PVC膜大变形状态下的力学特性,设计试验方案展开了PVC膜室内应力松弛特性试验,并监测了初始延伸率分别为50%、80%和125%状态下拉力值的变化;在试验数据分析成果的基础上,运用广义Maxwell和分数阶两种模型分别描述了PVC膜应力松弛规律,对比分析了模型的优劣。结果表明:分数阶模型可更精确地描述和预测高面膜堆石坝周边缝处PVC膜长期单向拉伸变形状态下的应力松弛性能,选用长时间序列应力松弛试验数据验证了模型预测应力松弛成果的准确性。应力松弛后试样断裂延伸率衰减较大,建议在设计施工时采取工程措施保证膜防渗结构的安全性。研究成果可在高面膜堆石坝周边缝处面膜结构设计方案时参考使用。
Abstract
Under load, the differential displacement of dam body/abutment at the peripheral joints of high geomembrane-faced rockfill dam (GFRD) causes the PVC geomembrane to be in a state of large deformation and tension. Indoor stress relaxation test was conducted on PVC geomembrane to investigate its mechanical properties under large deformation after differential displacement stabilizes. The change of tension at initial elongations of 50%, 80%, and 125% was monitored. According to analysis results of the test data, the stress relaxation law of PVC geomembrane was described respectively with generalized Maxwell and fractional order models. The advantages and disadvantages of the two models were compared and analyzed. Results suggest that the fractional order model can more accurately describe and predict the stress relaxation performance of PVC geomembrane in long-term uniaxial tensile deformation state at surrounding joints of GFRD. The accuracy was verified by using long-term stress relaxation test data. After stress relaxation, elongation at break of samples attenuates greatly. Engineering measures are recommended to ensure the safety of anti-seepage geomembrane structure during design and construction.
关键词
高面膜堆石坝 /
应力松弛 /
PVC膜 /
周边缝 /
Maxwell模型 /
分数阶模型 /
面膜结构设计
Key words
high GFRD /
stress relaxation /
PVC geomembrane /
peripheral joints /
Maxwell model /
fractional order model /
geomembrane structure design
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参考文献
[1] ICOLD. Geomembrane Sealing Systems for Dams: Design Principles and Return of Experience (Bulletin 135) Paris:The International Commission on Large Dams,2010.
[2] 束一鸣, 吴海民, 姜晓桢, 等. 高面膜堆石坝周边的夹具效应机制与消除设计方法: 高面膜堆石坝关键技术(二). 水利水电科技进展, 2015, 35(1): 10-15.
[3] 花加凤, 束一鸣, 张贵科, 等. 土石坝坝面防渗膜中的夹具效应. 水利水电科技进展, 2007, 27(2): 66-68.
[4] 顾淦臣. 土工膜用于水库防渗工程的经验. 水利水电科技进展, 2009, 29(6): 34-38, 48.
[5] 岑威钧, 温朗昇, 和浩楠. 水库工程防渗土工膜的强度、渗漏与稳定若干关键问题. 应用基础与工程科学学报, 2017, 25(6): 1183-1192.
[6] 束一鸣, 吴海民, 姜晓桢. 中国水库大坝土工膜防渗技术进展. 岩土工程学报, 2016, 38(增刊1): 1-9.
[7] BLACK P J, HOLTZ R D. Performance of Geotextile Separators Five Years after Installation. Journal of Geotechnical and Geoenvironmental Engineering, 1999, 125(5): 404-412.
[8] 马彦华, 宣传忠, 武 佩, 等. 玉米秸秆振动压缩过程的应力松弛试验. 农业工程学报, 2016, 32(19): 88-94.
[9] DU X,WANG C, GUO W,et al. Stress Relaxation Characteristics and Influencing Factors of Sweet Sorghum: Experimental Study. BioResources,2018,13(4):87618774.
[10] KELLY P A. A Viscoelastic Model for the Compaction of Fibrous Materials. Journal of the Textile Institute, 2011, 102(8): 689-699.
[11] AJN D, GERAK J, FLAJS R. Prediction of Stress Relaxation of Fabrics with Increased Elasticity. Textile Research Journal, 2006, 76(10): 742-750.
[12] SCOTT BLAIR G W, CAFFYN J E. VI. an Application of the Theory of Quasi-Properties to the Treatment of Anomalous Strain-Stress Relations. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 1949, 40(300): 80-94.
[13] KOELLER R C. Applications of Fractional Calculus to the Theory of Viscoelasticity. Journal of Applied Mechanics, 1984, 51(2): 299-307.
[14] STIASSNIE M. On the Application of Fractional Calculus for the Formulation of Viscoelastic Models. Applied Mathematical Modelling, 1979, 3(4): 300-302.
[15] NONNENMACHER T F, GLCKLE W G. A Fractional Model for Mechanical Stress Relaxation. Philosophical Magazine Letters, 1991, 64(2): 89-93.
[16] 陈 亮, 陈寿根, 张 恒, 等. 基于分数阶微积分的非线性黏弹塑性蠕变模型. 四川大学学报(工程科学版), 2013, 45(3): 7-11.
[17] KANG J, ZHOU F, LIU C, et al. A Fractional Non-Linear Creep Model for Coal Considering Damage Effect and Experimental Validation. International Journal of Non-Linear Mechanics, 2015, 76: 20-28.
[18] SIMPSON R, JAQUES A, NUEZ H, et al. Fractional Calculus as a Mathematical Tool to Improve the Modeling of Mass Transfer Phenomena in Food Processing. Food Engineering Reviews, 2013, 5(1): 45-55.
[19] 郭文斌, 王志鹏, 候智博, 等. 秸秆-薯渣混合物料应力松弛分数阶模型的建立及参数分析. 农业工程学报, 2021, 37(13): 284-290.
[20] SL 235—2012,土工合成材料测试规程.北京:中国水利水电出版社,2012.
[21] ZHANG X, MA Z, WU Y, et al. Response of Mechanical Properties of Polyvinyl Chloride Geomembrane to Ambient Temperature in Axial Tension. Applied Sciences, 2021, 11(22): 10864.
[22] 舒乐华,谢桂兰,曹尉南,等. 基于均匀化理论粘弹性复合材料松弛规律的研究. 新技术新工艺,2010(9):88-90.
[23] 张少实. 复合材料与粘弹性力学.2版.北京: 机械工业出版社, 2011.
基金
国家自然科学基金项目(52009045);河南省科技攻关项目(212102310539)
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