| Piping is one of the major causes of failures in dams,embankments and other water conservancy facilities.The occurrence and development of piping is the process of the coupling of soil particle erosion,seepage field redistribution and the changes of stress state.To reveal the regularity of the flow development of particle erosion,seepage and stress interaction in the process of piping,based on some existing theories.The erosion-infiltration-stress tests of the non-viscous granular soils under upward seepage conditions have been carried out,the erosion-seepage-stress coupling mechanism of the soil piping under the influence of stress state,particle gradation and dry density has been explored.The research results can provide reference for the prevention and control of seepage damage of hydraulic engineering.The main content of this article and its important results include:⑴ A piping erosion-seepage-stress coupled test system was developed.Improved pressure control system in a bulk earth pipe-erosion test apparatus,use weights to increase the axial pressure replace to cylinder pressure.Improved the confining pressure device to increase or decrease in real time.It can effectively simulate the development process of the upwelling failure of the upward seepage in the state of complex stress⑵ Using the self coupled erosion-seepage-stress test system,Respectively to carry out the stress state,grain size distribution,under the influence of density,grain caused soil erosion-seepage-stress research,based on the test results,analyzes the seepage flow and hydraulic gradient in the process of piping erosion change rule,reveals the particle erosion law of stress state,grain size distribution,granular soil under the condition of compactness.Further analysis of the accumulated sand quantity and sample volume variation in the process of piping erosion change rule,the stress state,grain size distribution,obtained The effects of stress state,particle size distribution and particle size on soil erosion and deformation.⑶ Based on The grain soil erosion-seepage-stress test results,monitoring the different of fine particle loss for real-time and the fine particle loss of the confining pressure value when the shear failure occurs,through the conversion formula.Obtained the internal friction angle of soil,analysis of piping erosion test in the process of soil shear strength with the effect of the fine particle erosion,reveals the stress state and grain size distribution,density under the condition of grain soil particle erosion effect on soil strength.⑷ Based on grain soil particle erosion of the soil strength change rule,by assuming the sample stress path along with the change of fine particle erosion has carried out the grain caused soil erosion test,further reveals the evolution of soil mass stress state and the interaction between particles erosion conditions of the law of piping development. |
