景洪水电站坝基工程地质问题的研究

Study on the Engineering Geological Problems of Dam Foundation of Jinghong Hydropower Station

针对景洪水电站坝基存在的抗滑、变形稳定以及渗透稳定等主要工程地质问题,研究提出施工时结合改善抗滑稳定条件进行深挖置换处理;对G23、G27等破碎带宽度较大的结构面及G2、G16等结构面交汇部位除进行槽挖置换混凝土处理外,在槽内铺设层面钢筋,加密加深固结灌浆;还在G23挤压带宽度最大坝块的下游回填了5 m厚混凝土,并对整个坝基的岩体进行了系统固结灌浆;对建基面开挖后的少数残留缓倾节理,优先考虑挖除缓倾结构面上覆岩体、清除结构面表面岩片、铁锈并进行凿毛的处理方式,同时增设键槽及锚索等进行加固处理。这些措施取得了成效。

In view of main engineering geological problems of anti-slide, deformation and seepage stability existed in the Jinghong hydropower station, we put forward, based on the researches, that the treatment of deep excavation and replacement for improving anti-slide stability conditions should be taken during construction period. Meanwhile for wider crushed zones of G23 and G27 and the crossing position of G2 and G16, we placed the bedding steel bars in the trough and close and deep consolidation grouting besides the treatment of trough excavation for replacing concrete. We also backfilled the concrete of 5m thick downstream the dam block in the widest crushing zone of G23 and performed the systematic consolidation grouting in the whole dam foundation rock body. For the construction foundation surface, we cleaned the gentle-inclined joint, overburden rock body on the gentle-inclined structural surface, the surface rocky sludge, and conducted the roughening treatment and increased the key groove and anchorage cable for reinforcement. All these treatments have gained good effectiveness.