花凉亭水库砂壳坝的抗震性能分析与加固研究

Earthquake resistance performance and reinforcement of soil-shell dam of Hualiangting Reservoir

经过对花凉亭水库黏土心墙砂壳坝进行地质勘察取样试验和液化分析,由于其上游坝坡砂土密实度不够,在7度地震时,水下部分可能发生液化并产生滑坡,需要进行抗震加固处理。我国目前已进行过抗震加固的土石坝不多,工程经验较少,还没有成熟的加固设计方法和技术规范。本工程应用砂土动强度试验成果,采用动力有限元分析对大坝抗震加固方案进行技术论证,并提出了帮坡压重的抗震加固方案,即在上游坝坡的水下部分抛块石帮坡压重和水上部分填筑石渣料帮坡压重,有效解决了水库蓄水条件下的大坝上游坝坡的抗震加固问题,其经验可供类似工程借鉴。

Based on experiments and liquefaction analysis on geological samples, the underwater section of the sand-shell dam with clay-filled-wall of Hualiangting Reservoir may result in liquefaction and landslide when 7-scale earthquakes happen since the sand in dam slope in the upper reaches is not compacted enough. Reinforcement measures are needed to prevent earthquake. Currently, there are few earth and rockfill dams that have been reinforced against earthquakes in china, and the engineering experience is little. Therefore, there is not available mature reinforcement design methods and technical specifications. The present project uses the results of dynamic strength of soil, employs the dynamic finite element analysis to make technical verification on earthquake resistance and reinforcement schemes of the dam, and puts forward the slope-press reinforcing scheme for earthquake resistance, i.e., filling block stone into the underwater section of the upstream dam to press the slope and filling stone materials into the above-water section to press the slope. It efficiently solves the reinforcement issues for earthquake resistance of the dam slope in the upper reaches of dam when reservoir is impounded. Its experience may be helpful to the similar profects.