Abstract: It is of great significance to study the effect of repeated fluctuation of reservoir water level on the stability of slope. Considering the problem of water-rock interaction, uniaxial and triaxial compression tests were conducted on argillaceous sandstone at different dry-wet cycles, respectively. The results show that the deterioration degrees from high to low are as followed: peak strength, cohesion and internal friction angle. Meanwhile, the deterioration degrees of mechanical parameters increase with increasing the times of dry-wet cycles. In combination with Drucker-Prager criterion (D-P criterion) that widely used in geotechnical plastic mechanics, a new D-P yield criterion is put forward for argillaceous sandstone under different confining pressures and dry-wet cycles. By comparing the experimental value with the theoretical peak value calculated by the modified D-P yield criterion, the error is found less than 10 percent. Hence, the D-P yield criterion is feasible for argillaceous sandstone under dry-wet cycles in practical applications. This study provides a theoretical basis for yield strength of rock under the arbitrary confining pressure in practical engineering.

Key words: dry-wet cycle, triaxial compression, Drucker-Prager criteria, peak strength, argillaceous sandstone