某水库副坝坝基渗漏成因分析及渗透稳定性计算

Causes and Stability Analysis of Foundation Seepage of Auxiliary Dam for a Certain Reservoir

针对某水库副坝坝基长期存在的渗漏问题,在综合分析历次地质勘察结果的基础上,采用高密度电法对副坝进行无损探测,同时,采用有限元法对副坝渗流性态进行二维数值模拟,分析坝基渗漏对副坝渗透稳定性的影响。结果表明,副坝坝基渗漏主要是由于坝基存在强透水的砂砾石层;副坝坝基渗漏未彻底解决的主要原因是已采取的防渗措施不当或存在质量缺陷,1978~1979年实施的桩号0+678~0+700段沟槽防渗墙存在缺陷,2000年实施的灌浆效果不佳;防渗墙失效后,副坝坝基砂砾石层在校核洪水位工况下可能发生渗透破坏,建议进一步采用混凝土防渗墙对副坝坝基进行防渗加固处理。

Aiming at the long-term leakage problem of a certain auxiliary dam foundation,the non-destructive test of the auxiliary dam was carried out on the basis of comprehensive analysis of the results of geological survey.At the same time,two-dimensional finite element method was used to simulate the auxiliary dam,and the influence of seepage on the stability of the dam was analyzed.The results show that the foundation seepage of auxiliary dam is mainly due to the strong permeable gravel layer.The main reason for the leakage of the dam foundation is that the seepage control measures have been taken improperly or the quality defects exist.There are defects of groove impervious walls in stake 0+678~0+700in 1978~1979,and in 2000 the implementation of the grouting effect is poor.After the failure of the cutoff wall,the seepage damage may occur in the gravel layer under the condition of check flood level.It is suggested that the concrete anti-seepage wall should be used to reinforce the dam foundation.