DETERMINATION OF THE PERMEABILITY ON EFFECTIVE STRESS DEPENDENCE IN GEOMATERIALS BY THE DATA OF LAB EXPERIMENTS ON GAS SEEPAGE IN DISC SPECIMENS
The technology of making any-shape specimens of an artificial geomaterial (sand and cryogel as a binder) is developed and implemented. From the standard test data of cylindrical specimens, permeability 100-110 mD and deformation characteristics (Young modulus 0.7-0.8 GPa, Poisson ratio 0.21-0.23) of this material are determined. The laboratory bench is designed and manufactured for studying mass exchange processes in disc specimens with central hole in conditions of nonuniform stress state. By the seepage test data of discs subjected to radial quasistatic loading applied over the whole lateral surface, the dependence of permeability on the effective stress S is found. The approximation of this dependence by the decreasing exponential function of S produces the value of the exponent coefficient а=0.029 MPa-1, which is an order of magnitude greater than the geomaterial compressibility conventionally assumed as the estimate of а.