钻孔高压压水试验的数值模拟

NUMERICAL SIMULATION OF HIGH-PRESSURE INJECTION EXPERIMENT

为了从理论上进一步讨论高压水作用下岩体的渗透特性,建立考虑紊流、层流、扩张、劈裂、冲蚀和淤堵现象的应力场与渗流场耦合的连续介质模型和应力场耦合Oda渗透张量模型,并编制相应的有限元计算程序WS3D。采用该程序对惠州抽水蓄能电站的钻孔压水试验进行数值模拟,得到压力水头P与水流量Q的关系曲线(P-Q曲线)与高压压水资料吻合较好。同时,根据数值模拟中的现象和结果进行分析可知,在高压压水试验中,层流、紊流、扩张、劈裂、冲蚀、淤堵现象中的一种或几种现象共同作用决定P-Q曲线的类型。

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.