Numerical Assessment of Seepage Control Effects of Underground Powerhouse

For performance assessment and optimization design of the seepage control system in the Yagen underground. powerhouse, a numerical method combining a substructure technique, the variational inequality formulation of Signorini's type and an adaptive penalized Heaviside function (short for SVA method) was adopted. Numerical results of seepage flow behavior in the underground powerhouse area of the Yagen. Hydropower Station demonstrate that:. the seepage control effects of the layout are very outstanding, and the designed scheme is generally proper and effective;. the upper part of the drainage system has little effects in controlling leakage from reservoir, and hence the spacing of the drainage hole arrays at higher elevations can be properly enlarged;. the auxiliary drainage hole arrays play an important role in reducing leakage amounts into the underground caverns and pore water pressure in the surrounding rocks, so they are essential for the long-term safe operation of the underground powerhouse.