某混凝土重力坝前倾现象成因分析

Cause analysis of lean- forward phenomenon of a concrete gravity dam

西南某水电站混凝土重力坝原型监测资料显示,左岸坝段坝体和坝基上下游向水平位移存在向上游发展的趋势,即出现前倾现象。采用综合过程线对比分析、数学建模分析等多种手段,对大坝各监测项目进行了定性和定量分析,证实这种前倾现象是真实的,且估计为坝前泥沙淤积所致。大坝左岸基岩较为软弱,坝前逐年淤积加大了库底压重,使得上游库盘沉陷,从而呈现出大坝前倾的现象,而坝前淤积对大坝造成的具体影响值还需进一步研究探讨。

The prototype momtormg data of a concrete grawty dam m 5outheast China shows that the dam body and dam ibun- dation at the left bank is leaning toward the upstream direction. The qualitative and quantitative analysis results by using different analytical methods such as comprehensive process line contrast and mathematical modelling demonstrate that the leaning phenom- enon is real and the underlying cause is the sedimentation in front of dam. The bedrock of dam foundation at left bank is weak, and the sedimentation year by year in the front of the dam weights the bottom of reservoir, causing the sink of the upstream reser- voir base. The sedimentation phenomenon should be focused, and the effect of the sedimentation on the dam deserves further study.