摘要
地下水库坝体在水压环境下的稳定性是废弃矿井抽水蓄能电站长期安全运行的关键。针对地下水库真实水压环境,自主设计、研制伺服轴-水压联合试验装置,分析环境水影响方式,阐明轴-水压联合作用结构演化过程,判断坝体理论强度变化趋势,开展不同水压力环境坝体力学试验,确定水压对坝体试件力学性能影响规律,探讨细观断口形貌特征与宏观破坏形态。结果表明:真实水压环境对坝体试件产生水化学与水压力影响,涵盖7个方面的增强与弱化作用;试件水环境由外界围压水、贯通孔隙水、封闭孔隙水3个部分组成,在试件饱和及加载过程中水介质交互与裂纹扩展相互影响,水压力越大渗入量与影响越大;真实水压环境改变试件损伤量与有效孔隙,进而影响侧向有效应力与试件强度;随着真实水压环境的水压力增大,应力-应变曲线具有明显的屈服波动、强度先减小后增大、轴向应变则持续降低,试验机对试件的耗能逐渐减少,但耗散能占比增速加快;水压力增大后断口形貌处裂纹核数量减少,主裂纹依次为沿晶断裂-穿晶断裂-剪切破坏,细微裂纹数量增大,试件破坏形态经历张拉-张剪-剪切转变,且破坏愈加复杂,伴随崩脆声响。研究成果可提高地下水库监测评估准确性,并为废弃矿井抽水蓄能电站建设提供理论与试验依据。
The stability of the underground reservoir dam body under water pressure conditions is crucial for the long-term safe operation of abandoned mine water storage power stations.Therefore,in response to the actual groundwater pressure environment,an independently designed and developed servo-shaft-water pressure joint test device was created,and mechanical tests on dam bodies under different water pressures were conducted.The affecting ways of the environmental water were analysed,the evolution process of the joint action structure between the shaft and water pressures was clarified,and the theoretical strength trend of the dam body was determined.Furthermore,the effect law of the water pressure on the mechanical performance of dam body specimens was ascertained,and the characteristics of microscopic fracture surfaces and macroscopic failure modes were explored.The results indicate that the real water pressure environment affects the dam body specimens through both hydrochemical and hydrostatic pressure influences,encompassing seven aspects of reinforcement and weakening effects.The specimen water environment consists of three parts:external confining water,penetrating pore water,and enclosed pore water.During specimen saturation and loading processes,the interaction of water media and crack propagation mutually influences each other,with a greater water pressure leading to increased infiltration and impact effects.The real water pressure environment alters the specimen damage and effective porosity,thereby affecting lateral effective stress and specimen strength.As the water pressure in the actual environment increases,the stress-strain curve exhibits a significant yield fluctuation,where the strength decreases first and then increases,while the axial strain continues to decrease.The energy consumption by the testing machine on the specimen gradually decreases,but the proportion of dissipated energy increases rapidly.After the increase in water pressure,the number of crack nuclei at the fracture surface decreases,with the main fractures occurring sequentially as transgranular fracture,intergranular fracture,and shear failure.The number of fine cracks increases,and the specimen failure pattern undergoes a transition from tension to shear to shear-shear,becoming increasingly complex,accompanied by brittle collapse sounds.The research outcomes can enhance the accuracy of underground reservoir monitoring and assessment,providing theoretical and experimental foundations for the construction of abandoned mine water storage power stations.
作者
吕鑫
何祥
杨科
方珏静
张寨男
LYU Xin;HE Xiang;YANG Ke;FANG Juejing;ZHANG Zhainan(State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines,Anhui University of Science and Technology,Huainan,Anhui 232001,China;Institute of Energy,Hefei Comprehensive National Science Center(Energy Laboratory of Anhui Province),Hefei,Anhui 230031,China;School of Civil,Environmental and Mining Engineering,The University of Adelaide,Adelaide 5005,Australia)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2024年第9期2214-2224,共11页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(52130402)
安徽省重点研究与开发计划项目(202104a07020009)
国家留学基金委员会资助项目(202208340045)。
关键词
采矿工程
废弃矿井
地下水库坝体试件
真实水压环境
破裂断口
水压破坏机制
mining engineering
abandoned mines
underground reservoir dam body specimen
real water pressure environment
fracture surface
hydraulic fracturing mechanism
