混凝土坝坝基帷幕前扬压力的几个问题

Some Problems of Uplift in Front of the Curtain of Concrete Dam Foundation

混凝土坝帷幕前的杨压力直接关系到大坝的安全稳定．笔者依据实测扬压力资料，对照现行设计规范分析研究后指出，在多泥沙河流上，当坝前能形成铺盖时，坝踵设计扬压力可小于上游水深的规定与实测资料相符；帷幕前的实测扬压力图形超过规范假定值的情况不是个别现象，对其可能产生的不利效应需有充分的估计；帷幕前的扬压力水位在高库水位时产生脉冲上升和扬压力系数大幅度增大，是帷幕前坝基面应力状态趋向恶化的反映，应引起高度重视．

Based on the measured datas of uplift in front of the curtain of concrete dam foundation,compared with the current design criteria, this paper indicates that: if the blanket can be formed while the overloaded river runs to before the dam, the stipulation that the assumed datas of uplift of dam heel can be lower than the upstream water depth tallies with.the measured datas, the case that the measured value and figures of uplift in front of the curtain exceed the assumed value in the criteria is not rare, therefore the unfavourable effect caused by the uplift should be given full consideration, the uplift level in front of the curtain is raised due to pulse phenomenon at high reservoir level and the uplift coefficient is greatly raised, it reflects the deterioration trend of the stress on contact of dam foundation in front of curtain and should be pay great attention to.