面板堆石坝长效服役状态下微幅变形监测及其分析

Monitoring and analysis on micro-amplitude deformations of a concrete face rock-fill dam with long-term service conditions

  • 摘要: 受堆石料自身流变特性及外部因素影响,混凝土面板堆石坝在服役后较长一段时间内仍有持续的微幅变形增长,微幅变形的不断累积可对面板等防渗结构产生不利影响。针对传统监测手段精度低、频次少、测量结果难以反映大坝真实的后期变形特征这一缺陷,尝试将静力水准系统与引张线系统应用到面板堆石坝表面沉降与水平位移监测中。利用上述系统,对泽雅水库大坝开展持续5年的坝体表面变形监测。分析监测数据发现:(1)上述监测系统的精度与稳定性可满足堆石坝长效服役状态下微幅变形的观测需求。(2)泽雅水库大坝在运行近20年后,堆石体的流变仍未停止,近5年最大平均变形速率可达4.33 mm/a(沉降)和3.50 mm/a(水平位移)。(3)各测点位移发展速率总体上逐年降低,变形趋于稳定。研究结果可为同类型工程监测设计及堆石料流变研究提供参考。

     

    Abstract: The micro-amplitude deformations of concrete face rockfill dams (CFRDs) can last for a very long time due to creep effect and external influences. The seepage control system such as the concrete face can be damaged if these micro-amplitude deformations continue to grow. Traditional deformation measuring methods are suffering from low accuracy and low frequency, thus the data can hardly reflect the true deformation features of CFRDs. To improve this defect, the Hydrostatic Level System and the Tension Wire Alignment System are applied for measuring the vertical and horizontal surface deformations for Zeya Reservoir dam. After a 5-year continuous monitoring, the monitoring data reveals that: ①The above measuring system can meet the requirements of the long-term and micro-amplitude deformation monitoring. ②The deformaions due to material creep have not stopped even after 20 years, the max average vertial deformation and horizontal deformaion rate can reach 4.33 mm/a and 3.50 mm/a, respectively. ③The deformation rates are reducing gradually, thus the deformations tend to converge. The above findings can provide useful references for monitoring system design and creep behavior studying.

     

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