侧向应力对裂隙渗透性的影响

Effect of lateral stress on rock fracture permeability

目前不同试验者得出的侧向应力对裂隙渗透性影响的结果存在矛盾,其根本原因在于侧向应力对裂隙有多方面的影响。侧向应力引起裂隙开度增加、壁面磨损、充填物压缩。这些对裂隙渗透性有不同的影响。根据裂隙是否存充填物,建立了相应的三维应力对裂隙渗透性影响的表达式。当不存在充填物时,裂隙渗透性与侧向应力呈指数关系,当存在较多充填物时呈负指数关系。把两种情况写成统一的指数形式,认为裂隙存在少量充填或者裂隙壁面磨损时也是适合的。利用已有的试验成果对结果进行了验证,表明本文建立的表达式与试验结果符合得比较好。

There are contradiction conclusions from different experimenter of the influence of lateral stress on rock fracture permeability.The reason for this is that the lateral stress has multi-aspect influences on a fracture.The lateral stress may cause crack opening increase,fracture wall attrition and filing compression.All of these have different influences on the fracture permeability.Expression of the influences of three-dimensional stress on the fracture permeability has been established according to whether the filing material exists.The fracture permeability has an exponential relation with the lateral stress when filing material does not exist,and it has a negative exponential relation when there is plenty of filing material.We unify those two cases in the form of an exponential form,and consider that the exponential form is also suitable when a little filing material or the fracture wall attrition exists.Other experimenter＇s test results have been used to verify our conclusions,and reasonable fitting is obtained.