水库大坝地震基础液化动力分析

摘要

The seismic liquefaction of dam body and base greatly influence the safety of the dam .In this paper , the most dangerous dam section of Shi Lianghe reservoir was chose to be analyzed .The liquefaction evaluation of silt , medium sand and coarse sand was made according to the results of the standard penetration tests in -situ and dynamic tri -axial tests indoor;the results of them were also compared.The conclusions were drew to the dam stability with the effective dynamic stress method:some sections of the dam would be liquefied under earthquake including the filling silt under upstream shallow water of the dam and part of sands under the dam foundation .The saturation line was effec-tively decreased by using drainage prism ,therefore,the initial effective stress was increased and the liquefaction zone was reduced .The dam could be partly cracked and upheaval , but it′s still stable as a whole.Stone materials could be used to press the slope .%基础液化对大坝长效安全运行构成严重威胁，时常导致边坡失稳。选取石梁河水库大坝典型断面进行地震危险性分析，开展现场标贯试验和室内动三轴试验，对坝体堆土、坝基粉质黏土、中砂和粗砂进行基础液化判别，对坝基可液化土进行了有效应力动力响应计算。结果表明，在8度地震作用下，上游库水位以下坝体堆土浅层轻微液化，坝基中砂层局部液化；大坝可能存在裂缝和局部隆起，但整体稳定，加强排水对减少基础液化切实可行。