Model experimental study on the seepage of overburden soil layers above fractured rockmass due to coal-mining

Concrete blocks with fissures of different sizes are adopted to simulate mining fractured rock mass,and the clay,silt,coarse sand and gravel are used to compose 21 kinds of soil samples with different particle size distributions.Then,the types and mechanisms of the seepage deformation and failure of the unconsolidated soil layers across the caving zone and water flowing fractured zone within overburden,and the relationship between the critical percolation gradient of unconsolidated soil layers w...