摘要
本文在实验室中采用定常压力差法在围压10—20MPP、注水压力为2.5—12.SMPS条件下对新丰江水库区花岗岩及刘家峡水库区变质岩进行了渗透实验,观测到了岩石渗透率随围压、注水压力及时间变化的结果,并且得到了渗透率随时间衰减的经验关系l。(t)=k。XEXP(一、t)。实验结果表明:完整岩石、自然裂而中含填充物岩石、自然裂面岩石的渗透率依次增大两个数量级。在实验中,恒定注水压力时渗透率明显地随着围压的增大而减小,当国压变化发生循环时,渗透率产生了不可恢复的减小;当恒定因压时,渗透率随着注水压力的变化取决于流体水对裂面的冲刷、溶解及沉淀堵塞作用而不可预测。最后根据该实验结果讨论了水库地震中水沿断裂系统渗透过程中渗透水的前锋形成高孔隙压力而触发地震的机制。
In laboratory, using the constant pressure difference method rock permeability experiments have been carried out on granite in Xinfengjiang Reservoir Area and on metamorphic rock in Liujiaxia Reservoir Area, under an ambient pressure of 10-20 MPa and injection pressure of 2.5-12.5 MPa. The observed results show variations of rock permeability with ambient pressure, injection pressure and time, and the empiric relation of permeability attenuating with time K(t)=K0×ExP(-τt) is obtained. The experimental results indicate thatpermeabilities of intact rock, naturally cracked rock with fillings and naturally cracked rock enhance in turn two orders. In laboratory the permeability decreases abviously with the increasing ambient pressure under a constant injection pressure, whereas it goes to a decrement that can't recover when circulative variation of ambient pressure occurs) but its variation with injection pressure can't be predicted under a constant ambient pressure due to liquid water washing the parted planes, dissolution and sediment block function. Lastly, based on the experimental results the mechanism is discussed, which triggers an earthquake with high pore pressure formed by front of permeable water in the process of it permeating along fault system during a reservoir earthquake.
出处
《地震研究》
CSCD
北大核心
1990年第3期319-328,共10页
Journal of Seismological Research
基金
This project is aided financially by Earthquake Science Foundation.
关键词
岩石
渗透率
注水
压力
水库
地震
Rock permeability, Injection pressure, Xinfengjiang Reservoir, Liujiaxia Reservoir
