金沙江某水电站上下坝址岩体卸荷差异研究

油水乳化渗流是三元复合驱和热力采油过程中常见的现象，地层介质的微观 孔隙结构特征对乳状液流动有着重要影响. 现有描述乳状液渗流的理论模型都属于确定性方 法，只能反映出介质孔隙结构的体积平均效果. 当介质内部微观非均质性相比其尺寸不能被 忽略时，采用确定性方法描述会与实验结果存在偏差. 基于连续时间随机游走理论建立 了描述乳状液渗流的随机理论模型. 该模型引入反映液滴微观运动特征的跃迁时间和跃迁位 移两个概率分布函数来反映多孔介质微观非均质特征. 研究结果表明该模型能很好地刻画 实验曲线中出现的与介质尺度相关的拖尾现象，可作为更一般的过滤模型.

UNLOADING OF THE ROCKMASS |AT THE UP AND DOWNTREAM DAMS |OF HYDROPOWER STATION IN JINSHA RIVER

The process of stream trenching and slope formation cause a continuous change in  the stress field  of the river bank slopes. The superficial rockmass is unloaded in the change of stress field. The depth of unloading should be indifferent in the same area. An investigation is carried on the stress field at  a hydropower station in southwest China. The station has two dams.  The up and downtream dams have a distance  of 1.4km.  The investigation detected that unloading depths of the rockmasses at the two dam sites have wider differences. At the upstream dam site, the unloadin depth is more than 20m, and its extreme depth can reach to  90 m. At the downstream dam site, the unloading depthis only 5~20m. Field survey and numerical simulation indicate that orientation of the rock formation is the key factor for the difference in the unloading depths at the up and downstream dams.  Trends of rock formation and river bank slopes at the upstream dam are paralleled.  The rockmass of steep dip angle is easy to be cracked.  The weathering is invaded.  The depth of the rockmass unloading is deep.  At the downstram dam,  the trends of the rock formation and river bank slopes are nearly are perpendicular.  The strength of the rockmass is greater than the bedding planes.  The structural surfaces that parallel  to the river bank slopes  are less. Therefore, the unloading depth of rockmass is within 20m.