大理岩裂隙渗流的时间效应试验研究

Experimental Study on Time Effect of Seepage Properties of Marble Fracture

应用自行研制的辐射型渗流试验装置对含单个张裂隙粗晶大理岩进行不同法向应力作用下的渗流试验,分析法向蠕变对渗流特征与法向应力和水头大小关系的影响。结果表明:在恒定法向应力作用下,裂隙蠕变闭合量与时间呈对数函数关系,随时间增加而增大,呈现出明显的初始蠕变阶段特征;降水头阶段和升水头阶段渗流量均与水头差呈线性关系,岩石裂隙法向蠕变导致恒定法向应力下岩石裂隙渗流能力随时间增加而降低,降水头阶段与升水头阶段相同水头差处流量差值随水头差的增加而增大;在相同水头差作用下,降水头阶段和升水头阶段渗流量均与法向应力呈负指数函数关系,降水头阶段与升水头阶段相同法向应力处渗流量差值随法向应力增加而降低,其原因为裂隙蠕变闭合量与法向应力呈正线性关系。研究结果对岩体裂隙渗流工程实践具有一定参考意义。

Single fracture seepage tests under different normal stress were conducted by self-developed radial flow device for coarse-grained marbles with single tensile fracture,and the effect of the normal creep of rock joint on relationships between flow rate and normal stress,inlet water head were analyzed respectively. The results show that the fracture creep closure showing the characteristics of initial creep stage obviously increases and has an logarithmic relation with time under a constant normal stress; there is a positive linear relationship between flow rate and head difference in either head-decreasing stage or head-increasing stage; the normal creep of rock fracture led to conductive capacity of rock fracture decreasing with the increase of time under the constant normal stress,therefore,the flow rate difference between head-decreasing stage and head-increasing stage under the same water head increases with head difference; flow rate of fracture follows a negative exponential function with the normal stress in the head-decreasing stage and head-increasing stage under the same head difference; the flow rate difference between the head-decreasing stage and head-increasing stage under the same normal stress decreases with the normal stress,the reason is that fracture creep closure has a positive linear relationship with normal stress. The research results have some referencing value for the engineering application in rock fracture seepage.