长江科学院院报 ›› 2023, Vol. 40 ›› Issue (4): 141-149.DOI: 10.11988/ckyyb.20220422

• 水工结构与材料 • 上一篇    下一篇

PVC膜应力松弛特性

谷晓雨, 张宪雷   

  1. 华北水利水电大学 水利学院,郑州 450046
  • 收稿日期:2022-04-20 发布日期:2023-04-26
  • 通讯作者: 张宪雷(1984-),男,河南濮阳人,高级工程师,博士,硕士生导师,主要从事高面膜堆石坝面膜防渗结构研究工作。E-mail:zhangxianlei@ncwu.edu.cn
  • 作者简介:谷晓雨(1998-),女,河北邢台人,硕士,研究方向为水工结构工程。E-mail:guxiaoyu47@163.com
  • 基金资助:
    国家自然科学基金项目(52009045);河南省科技攻关项目(212102310539)

Stress Relaxation Characteristics of PVC Geomembrane

GU Xiao-yu, ZHANG Xian-lei   

  1. School of Water Conservancy, North China University of Water Resources and Electric Power, Zhengzhou 450046, China
  • Received:2022-04-20 Online:2023-04-26

摘要: 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。

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

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.

Key words: high GFRD, stress relaxation, PVC geomembrane, peripheral joints, Maxwell model, fractional order model, geomembrane structure design

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