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Abstract The piecewise seepage characteristics of closed tensile fracture and loading history effect were investigated at room temperature using cylindrical rock samples of coarse-grained marble，sandstone，limestone and fine-grained marble with self-developed radial flow system. The results show that fracture seepage can be divided into three phases of islands flow，transitional flow，and groove flow according to different contact states and watershed distributions. Flowrate per head follows an exponential function with the normal stress，and it will be significantly lower in the subsequent loading process at the same normal stress. The relationship between flowrate per head and mechanical aperture was well simulated by the power function，in which the range of index is 1.93–2.60，so that sub-cubic law could be used to describe seepage in contacted rough rock fracture；flowrate per head is significantly lower at same mechanical aperture in subsequent loading process. Moreover，there is a piecewise linear relationship between equivalent hydraulic aperture and mechanical aperture，therefore，the modified cubic law can be established in each appropriate phase. The results have some theoretical significance for calculation of rock fracture seepage.
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Received: 16 January 2011
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2012, Vol. 31 
