镇安抽水蓄能电站弃渣坝材料大型三轴试验研究

Large Scale Triaxial Test Study on Waste Slag Dam Materials of Zhen’an Pumped Storage Power Station

根据镇安抽水蓄能电站弃渣坝地质条件和现场实际工况,通过对不同干密度土料开展土工试验,分析了坝体材料各力学参数特性。试验结果表明:随着围压增大,该坝弃渣料的峰值应力相应增大;在低应力情况下,弃渣料的体积缩小,在围压较高时,体积变化增大;弃渣料先出现剪缩,随后变为剪胀,剪胀随着侧压力的增大出现缩小现象,应力-应变关系曲线呈软化型,最终转变为剪缩型;保持围压条件不变,材料的峰值应力在干密度逐渐增大的情况下出现略微增大,但最大体变随着干密度增大出现较明显的减小情况;保持相同围压状态,邓肯-张模型参数对干密度的敏感性大小依次为Kb、k、m、c、Δφ、Rf、φ0、n。相关研究可为以后抽水蓄能电站的弃渣坝设计和后期防护奠定理论基础。

According to the geological conditions and actual working conditions of the waste slag dam of Zhen’an Pumped Storage Power Station,geotechnical tests were carried out on soil materials with different dry densities to analyze the characteristics of various mechanical parameters of the dam material.The test results show that as the confining pressure increases,the peak stress of the waste slag material increases accordingly.In the case of low stress,the volume of the waste slag material decreases.When the confining pressure is high,the volume change increases.First shear shrinkage and then dilatancy appears in the waste slag material,and the dilatancy shrinks with the increase of lateral pressure.The stress-strain relationship curve becomes softened,and finally is transformed into a shear shrinkage type.Keeping the confining pressure constant,we can find that the peak stress of the waste slag material increases slightly when the dry density gradually increases.However,the maximum volume of the waste slag material change appears to decrease significantly with the increase of dry density.Keeping the same confining pressure state,we can find that the sensitivity of Duncan-Chang model parameters to dry density is Kb,k,m,c,Δφ,Rf,φ0 and n in proper order.The relevant research can lay a theoretical foundation for the design and later protection of the abandoned slag dam of the pumped-storage power station in the future.