Study On Slope Stability Under Seepage Action

Earth slope stability under transient seepage action is a complex issues which both involves in hydraulics and soil mechanics. Unsteady seepage generated by reservoir water level rise or rapid drawdown goes against the slope stability of dams and embankments.For the slopes with unsteady seepage as, there is important theoretic and practical value to assessment the stability combine with the complex groundwater flow pattern in the slopesTheoretical analysis method, physical model test and numerical simulation method were used to analyze the change law of the grounder flow field and the fluency on the earth slope stability. First of all, the basic theory has been systematic analyzed, then the physical process of the slope which constructed by material such as silt, fined sand, and clay in the transient seepage through the sandbox experiment has been observed, the slid phenomena of the slope has been inspect. The dynamic response of unsaturated seepage flow field stimulated by the rapid drawdown velocity of reservoir water level has been mainly studied, and the effect of direction of the seepage and seepage force on slope stability has been studied.Base on the test results of the sandbox, through the distribution of head, seepage gradient and the internal relations between these property and time variation, the unsaturated seepage law caused by recession flow index k/μv has been mainly studied, and the calculation formula of the highest point of the phreatic line has been further perfected.The analysis shows that, the seepage direction is the key of slope stability, the equipotential lines are parallel to the slope when the reservoir water level rapid drawdown, this moment, the seepage direct to the upstream slope. The slope failure when the seepage force and seepage gradient in the upstream slope at the peak. So, we suggest that the slope stability should combine the seepage action.