大坝浇筑过程中坝基岩体压密效应研究

Study of compaction effect of dam foundation rock mass during concrete grouting process

为了解大坝混凝土浇筑过程中坝基岩体的压密效应,利用大岗山水电站坝基固结灌浆后长观孔的单孔声波及钻孔全景图像测试成果,对大坝浇筑过程中坝基岩体压密效应的影响因素、坝基岩体压密的时效性及钻孔全景图像特征进行了研究。结果表明,随着浇筑厚度的增加,坝基岩体表现出明显的压密效应,岩体波速逐步提高,裂隙的张开度逐步减小甚至消失;混凝土盖重厚度和岩体初始波速是影响岩体速度提高的重要因素。研究结果可为最终的固结灌浆验收提供依据。

In order to understand the compaction effect of dam foundation rock mass during concrete grouting process,the influential factors on compaction effect,the timeliness of compaction and features of drilling panoramic picture were studied by using testing results of single-hole sound-wave and drilling panoramic picture of long-term observation hole after consolidation grouting. The results show that the dam foundation rock mass has an obvious compaction effect with the increase of the grouting thickness,the rock mass velocity increases gradually and the joint opening decreases or even disappears; the concrete cover thickness and initial rock wave velocity are key influential factors on rock wave velocity increment.