Abstract：Conventional injection experiment was conducted to investigate the hydraulic behavior of a rock mass. With the development of hydraulic engineering，conventional injection experiment can not satisfy the need for estimating hydromechanical character of rock mass or providing enough information to engineering design and seepage control. High-pressure injection experiments have been carried out in many hydropower engineering projects recently. In order to analyze the seepage characters of rock mass in high pressure injection experiment，some basic presumptions and theories considering effects of laminar flow，turbulence，erosion，silting，cracking，were established；and corresponding finite element method program WS3D was developed. With those presumptions and theories，the high pressure injection experiment of Huizhou pumped storage power station in Guangdong Province was simulated by continuum method and Oda tensor method coupled with stress field. Curves of water pressure head versus flow quantities(P-Q curves) were achieved by numerical method. The result has a good agreement with that of high-pressure injection experiment，and the phenomenon and results in the simulation process were analyzed. Conclusions were drawn that P-Q curve is the syntheses of those effects and the type of P-Q curve is determined by the combination of those effects.
