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基岩裂隙渗水在浇筑混凝土以前必须进行妥善处理,否则将严重地危害混凝土的质量。丹江口27坝段防渗板的基岩系闪长玢岩,裂隙发育,加上有破碎带和裂隙互相切割,因而渗水严重,极强透水带单位吸水量达0.111～0.237公升/分。又由于基岩有一宽达20多米、深达9米的深槽,地下水从两侧流入。同时在施工中为了截断深槽上游基岩面以上的渗水,作了一道高8米的混凝土截水墙,墙上游水头经常维持在6～7米,水从基岩裂隙向下游深槽渗透,因而形成了一集中渗流带。由于地表、地下水的集中,大大地增加了施工的困难和延长了工期,27坝段防渗板混凝土浇筑比一般不需处理渗水的坝段要多花1个多月的时间。但在工地党委的正确领导下,由于采取了一系列的有效措施,终于克服了困难,战胜了渗水。一、处理措施 (一)截断地表水不截断地表水,就无法处理地下水。因此首先在基岩深槽上游面作了一道混凝土截水墙,以截断
Bedrock fissure seepage must be properly handled before pouring the concrete, otherwise it will seriously endanger the quality of concrete. Danjiangkou 27 dam anti-seepage plate bedrock diorite rock, fracture development, coupled with broken and fissure cutting each other, and thus seepage serious, very strong water permeable water absorption unit amounts to 0.111 ~ 0.237 l / min. Since the bedrock has a deep trough with a width of more than 20 meters and a depth of 9 meters, groundwater flows in from both sides. In the meantime, in order to cut off the water seepage above the bedrock surface in the deep trough, a concrete cutoff wall of 8 meters in height was constructed. The water head of the wall was always maintained at 6 ~ 7 meters. The infiltration of water from the bedrock fissure to the downstream deep trough, Thus forming a concentrated seepage zone. Due to the concentration of ground surface and groundwater, the difficulties in construction and the extension of the construction period have been greatly increased. The anti-seepage concrete of 27 dam has to be poured more than one month longer than that of the dam without water seepage. However, under the correct leadership of the construction party committees, due to a series of effective measures, it finally overcame the difficulties and defeated the seepage. First, the treatment measures (A) cut off the surface water does not cut off the surface water, it can not handle groundwater. Therefore, first of all, a concrete cutoff wall was made on the upstream face of deep bedrock to cut off