伊朗卡尔赫工程坝基软岩防渗处理方案选择

非裂隙性软岩坝基防渗措施，要论证并选择一合理的方案，常使工程师们困惑．伊朗卡尔赫工程坝基地层，以软弱砾岩为主，基本无节理、裂隙，透水性中，砂粒含量高，胶结差，强度低．初设阶段采用帷幕灌装防渗方案．扩大初设阶段进一步论证了灌浆方案是否可行，能否形成连续防渗幕，以及造价工期问题．经进一步进行地质资料分析，砾岩可灌性判别，两次灌浆试验，渗流分析计算，混凝土防渗墙方案可行性研究和防渗效果计算，以及两方案的造价、工期比较等工作，最后结论是：灌浆方案在技术上近乎不可行，造价高，工期长；混凝土防渗墙方案无论从技术上、经济上、工期上都具有明显优点．

The Anti-seepage Treatment of Soft Rock on Karkheh Dam Foundation of Iran

Engineers often feel some troubles when they attempt to demonstrate and select a resonable anti-seepag aternative for soft rock dam foundation- A stratum on Iran Karkheh dam mainlyconsist of soft conglomerate and its characteristics are: few joint and few fracture, middle permeability, higher Sand content, weak cementation, and low strength. The grouting curtain used as antiseepage treatment on dam foundation was accepted in the preliminary design stage. During the secondary design stage, following problems were further studied: whether the rock can be grouted, acontinue anti-seepage curtain can be performed or not, what is about the cost and construction time.After the works-further analysis of the geological data, groutability judgement of the conglomerate, grouting tests for two times, seepage analysis in dam body and foundation, feasibillty study andthe calculation of anti-seepage efficiency for concrete cut-off wall, and the comparison of economicand construction time between two alternatives were completed within two years. The final conclusionwas that the grouting almost is unfeasible on technigue with higher cost and long time on construction. Whereas the conerete cut-off wall has much advantages on technique, economy,and constructlon time.