邓刚,陈辉,张茵琪,张延亿,张幸幸,侯伟亚.基于坝壳湿化过程数值模拟的心墙坝初蓄水力劈裂机理研究[J].中国水利水电科学研究院学报,2021,19(1):90-98
基于坝壳湿化过程数值模拟的心墙坝初蓄水力劈裂机理研究
Study on mechanism of hydraulic fracture of earth core embankment dam during first filling based on the numerical simulation of wetting deformation development with time of coarse aggregate
投稿时间:2020-07-23  
DOI:10.13244/j.cnki.jiwhr.20200144
中文关键词:  土质心墙土石坝  水力劈裂  湿化变形  时间过程  数值模拟
英文关键词:earth core embankment dam  hydraulic fracture  wetting deformation  timely development  numerical simulation
基金项目:国家重点研发计划课题(2017YFC0404803);中国水科院基本科研业务费专项(GE0145B562017,GE0145B102020);流域水循环模拟与调控国家重点实验室自主研究课题(SKL2020ZY09)
作者单位
邓刚 中国水利水电科学研究院 流域水循环模拟与调控国家重点实验室, 北京 100038 
陈辉 中国水利水电科学研究院 流域水循环模拟与调控国家重点实验室, 北京 100038 
张茵琪 中国水利水电科学研究院 流域水循环模拟与调控国家重点实验室, 北京 100038 
张延亿 中国水利水电科学研究院 流域水循环模拟与调控国家重点实验室, 北京 100038 
张幸幸 中国水利水电科学研究院 流域水循环模拟与调控国家重点实验室, 北京 100038 
侯伟亚 中国水利水电科学研究院 流域水循环模拟与调控国家重点实验室, 北京 100038 
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中文摘要:
      初次蓄水过程中的水力劈裂破坏是土质心墙土石坝面临的最主要安全问题之一。为探索这一难题,回顾了疑似水力劈裂事故及暨有研究尚不能回答的问题,探讨了水力劈裂所需的必备应力条件和可能原因。分析了既有浸水湿化变形试验并建议了采用时间对数演进模式、单位时间湿化体变和湿化剪应变分别取决于围压和剪应力水平的湿化变形时间过程计算模型,并应用于模型坝数值模拟,再现了初蓄过程水力劈裂破坏所需应力条件,得到了顺岸坡方向上后期变形增量空间分布导致心墙拉伸和水力劈裂破坏的机理。最后提出了确保坝壳压实度、控制后期浸水后变形,保证心墙与坝壳后期变形量值和速率协调为核心的水力劈裂防控方法建议。
英文摘要:
      The hydraulic fracture during first filling is one of the main safety issues of earth core embankment dams. The phenomena and unsolved problems in research of suspected hydraulic fracture accident are reviewed in the paper. The stress conditions needed for hydraulic fracture damage, along with the possible reason are analyzed based on case study and theoretical analysis. The wetting deformation experiments of rockfill are also reviewed. A computation model to analyze the timely development of wetting deformation is proposed, in which a logarithm of time is linearity with wetting deformation. The computation method for wetting volumetric strain and shear strain in unit time, which depends on confining pressure and shear stress respectively, is included in the model. The wetting deformation model is applied to one hypothetical dam. The stress condition needed for hydraulic fracture is reappeared in the simulation. A new mechanism of hydraulic fracture is suggested, that it is the differential displacement along bank slope between earth core and rockfill shell because of spatial distribution of long term deformation increment after impounding which leads to hydraulic fracture. Suggestions to avoid hydraulic fracture for better safety assurance is put forward,including insuring the compaction density of rockfill and controlling of wetting deformation. The deformation value and rate of earth core and rockfill shell should be coordinated to ensure the dam safety.
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