The shear strength deterioration of bedding planes between different rock types induced by cyclic loading is vital to reasonably evaluate the stability of soft and hard interbedded bedding rock slopes under earthquake. In this study, experimental investigations on shear strength weakening of DDJM under cyclic loading were conducted by taking the interface between siltstone and mudstone as research objects. Similar material samples of DDJM and DIJM with typical surface morphology were fabricated. Cyclic shear tests were conducted on these samples considering the effects of normal stress, joint surface morphology, shear displacement amplitude and shear rate. The results indicate that the shear stress vs. shear displacement curves under each shear cycle and the peak shear strength vs. cyclic number curves of the studied DDJM are between those of DIJM with siltstone and mudstone, while closer to those of DIJM with mudstone. The peak shear strengths of DDJMs exhibit an initial rapid decline followed by a gradual decrease with the cyclic number. The normal stress, joint surface morphology, shear displacement amplitude and shear rate collectively influence the shear strength deterioration of DDJM under cyclic shear loading.

Discontinuities with different joint wall material,Discontinuities with identical joint wall material,Cyclic shear test,Shear strength deterioration,Joint surface morphology,Shear displacement amplitude,Shear rate,Normal stress