Research On Seepage And Deformation Of Debris Flows Silt Trap Dam Foundation By Different Rainfall Frequencies

Recent years, in southwestern of China, occurred several large or smallearthquakes, Wenchuan earthquake was a heavy blow to the country and the peoplewhich happened on May12,2008. It made69,227people lost their lives,374,643people injure and17,923missing, economic losses amounting to845.2billion, thosehuge and distressing number alarm us all the time. However，just on April20,2013,Lushan County, Ya’an City, Sichuan Province, occurred earthquake measured at7.0Ms.Debris flow as a secondary disasters after the earthquake always happened with theheavy rainfall, threatens the lives and property of the people of disaster areas. Debrisflows filt trap dam as a governance measure is always used to govern debrisflows,while,during the process of construction and operation, dam foundation seepagedeformation will cause the dam failure and resulting in greater losses on downstream.But, the research on the seepage and seepage deformation of debris flows filt trap damfoundation is rare.Based on the above background, the paper combines theoretical study andnumerical analysis to research the seepage and seepage deformation of the damfoundation when mudslides silt up behind dam. research and results are as follows:(1) The paper researched the seepage principle of the dam foundation, andcombined rainfall and the height of debris flows silted, used multi-layer soil percolationtheory to study the dam foundation seepage and seepage deformation, researched therange of poermeability coefficient of debris flows and dam foundation. Summarized thetype of dam foundation seepage deformation and the method for distinguishing seepagedeformation.(2) Used GeoStudio to simulate and analyze the seepage and seepage deformationof the dam foundation under different rainfall conditions, reaearch the influence of thepermeability coefficient of debris flow behind dam to the seepage and seepagedeformation of the dam foundation. Get the results about seepage velocity, pore waterpressure and the hydraulic gradient of the different locations in front of the dam.(3) Take the prevention engineering of Zoumaling debris flow as an example, useand verify the result of the percolation theory and numerical analysis by comparisingand analysising the result of the numerical simulation.Finally, investigated the rangemay occur dam foundation seepage deformation by comparising the hydraulic gradient of the different locations in front of the dam with the critical hydraulic gradient.Proposed the treatment methods of the seepage deformation of Zoumaling debris flowdam foundation, and verified the reliability of the method of treating by the numericalsimulation, in order to actually play a guiding role in future projects.