水布垭面板堆石坝坝体后期变形时空分布规律研究

通过分析水布垭面板堆石坝的长期实测变形资料,对最大坝高断面和下游坝面的后期变形情况进行研究,揭示了坝体后期变形的时空分布规律。研究表明:沉降是坝体后期变形的主要形式;后期沉降增量基本随高程升高而增大,但后期水平位移增量的分布未表现出与高程的相关性;下游坝面后期变形阶段的三向变形增量的分布规律与面板堆石坝一般变形规律类似;最大坝高断面和下游坝面的变形发生时序存在差异,下游坝面的变形大多在后期变形阶段发生,而最大坝高断面的沉降主要发生在后期变形阶段之前;此外,坝内各测点的年沉降增量演化均呈现出一定的波动性;下游坝面测点的历年沉降增量有明显分布规律,且各测点的年沉降增量基本呈逐年减小趋势。根据坝体后期变形时空分布规律,适当提高坝体中上部,特别是中上部下游侧筑坝料的填筑标准,对降低坝体后期变形能起到良好效果。

Spatiotemporal Distribution of Post-operation Deformation of Shuibuya Concrete-faced Rockfill Dam

By analyzing long-term monitoring data, we examined the post-operation deformation (defined as the deformation in stable running stage) of the maximum-height section and the downstream surface of Shuibuya concrete-faced rockfill dam (CFRD), and hence revealed the spatiotemporal distributions of post-operation deformation of the dam. We found that settlement is the dominant form of deformation in the stable running stage of the dam. The increment of settlement in stable running stage increased with the rise of elevation, while the increment of horizontal displacement bore no correlation with elevation. The increment of tri-directional deformation of the downstream surface in stable running stage was similar to that of general deformation of CFRD. The deformation time of maximum-height section differed from that of downstream surface: the deformations of downstream surface mostly occurred in the later stage, while the settlement of the maximum-height section was observed mainly before the later stage. Moreover, the annual settlement increment of each monitoring point fluctuated. The distribution of the annual settlement increment of the downstream surface was obvious, and the annual settlement increment of almost all monitoring points at downstream surface showed a decreasing trend with time. According to the research results, we recommend to improve the compaction quality of dam materials in the middle-upper part of the dam, especially on the downstream side in order to control the post-operation deformation of the dam.