软弱泥化夹层高压渗透失稳孕育演化细观机理研究

Clay gouged intercalation is weak geological structure. It is very common in hydropower engineering and other geotechnical engineering which is the key factor in seepage failure causing serious accidents in some projects, such as dam foundation failure, slope instability and tunnel leakage. However, its seepage failure mechanism is not been studied adequately. In this work, the permeability properties, seepage failure modes and failure process of clay gouged intercalation under high water pressure are researched to reveal the meso-mechanism, gestation and evolution law of seepage failure. First of all, the material composition, grain composition, meso structure and physical and mechanical properties of clay gouged intercalations are studied according to scene investigation and test in laboratory. Secondly, based on seepage deformation tests of samples, the permeability properties and seepage failure modes are studied to reveal its seepage failure mechanism and impact factors. On these bases, the estation and evolution process of seepage failure are revealed by tracer technique, observation and record in test period. Finally, the seepage stability analysis method is put forward to reduce the risks of seepage failure in weak clay gouged intercalation. Meanwhile, the proposed method will be constantly tested and corrected in engineering application. The rational recommendations in this work will be made for the design and construction in hydroelectricity engineering, geotechnical engineering and foundation engineering such as high dam, high pressure shaft, embankment dam and levee, and providing useful scientific evidence and analysis method for seepage control and disaster reduction.

软弱泥化夹层是水利水电工程中常见的工程地质问题，在工程渗透失稳中起关键作用。本项目研究高水头作用下软弱泥化夹层的渗透特性、破坏模式及失稳过程，揭示其渗透失稳的细观机理和孕育演化规律。首先采用现场调查、室内试验等手段，获得软弱泥化夹层的物质组成、颗粒级配、细观结构及内部形态特征及物理力学性质。进而采用室内渗透变形试验，研究不同条件下软弱泥化夹层的渗透特性及破坏特征，揭示其渗透破坏机理、控制性影响因素及影响规律。通过试验过程示踪和观察记录，揭示软弱泥化夹层渗透失稳的孕育发展过程和演化规律。在此基础上，提出高水头作用下裂隙岩体软弱泥化夹层的渗透稳定性分析评价方法，推广应用到实际工程中并逐步检验、修正和完善。研究成果可为高坝、高压管道及堤防等工程的安全评价和防渗减灾控制提供科学依据和分析手段。

本研究针对软弱泥化夹层渗透稳定性极差的工程难题，通过工程特性研究、室内试验及理论分析方法，对软弱泥化夹层的渗透破坏特性、破坏机理、演化过程等展开了系统研究，对高水头作用下裂隙岩体软弱带的渗透特性、渗透破坏失稳模式及孕育演化过程有了更深刻的认识。通过现场复杂的试样制样过程和设备改进，获得了可靠的试验数据，并针对目前无合适评价方法的现实情况，提出了软弱泥化夹层渗透稳定性评价方法。研究成果为高水头电站渗控设计和工程处理措施制定提供了依据，提升高水头电站的设计水平和工程安全。对水工岩石力学及深部岩石力学理论的发展具有重要推动作用和现实科学意义，同时对西部常规高水头电站、东部抽水蓄能电站、堤防等工程的优化设计与施工、安全评价及防护，减少和防止因渗透破坏引起的工程事故和地质灾害等具有重要工程应用价值。