ABSTRACT
In order to overcome the inadequate size of laboratory specimens and namely to take into account the influence of blocks, six non conventional in situ shear tests were carried out on specimens of 0.3 m3 in volume.The testing procedure ensures that the shear plane is free to develop inside the specimen and to negotiate in a tortuous way along the block/matrix boundaries; thus differing from the ISRM Suggested Method for In Situ Shear Tests (ISRM, 2007). This aspect has a very important role in shear tests performed on bimrocks: the main consequence for the presence of blocks, in fact, is an increase in tortuosity of the shear plane that causes the increase in shear strength.
