Advances in the research on saturated seepage flowin low permeability rock masses

Groundwater flow in low permeability media can affeect the evolution of certain hydrological and geochemical systems and can impact the accumulations for petroleum and ores too.Such low permeability media are also important in the fields of waste disposal,engineering safety and environment changes.Although the Darcy's law is usually used as a fundamental as sumption in the studies of seepage flow theory for long period,its applicability has not been well tested in the range of very low pressure gradient in conforming with reality.It is more difficult to analyze the flow in low permeability media due to the complexity of hydrogeological conditions and the difficulties of measuring hydraulic head and sampling pore fluids.This paper reviews and summarizes studies on saturated seepage flow in low permeability media and discusses non-Darcy flow,coupled seep-age flow under multi factors,as well as two important nonhydraulic flow phenomena like osmosis and ultrafiltration.The problems of affecting and hindering analysis are discussed and some suggestions are also proposed for studies.