Experimental study on compressive strength and fracture characteristics of sandstone containing double circular cavities

A large number of micro cracks,holes and other defects appear in the rock material because of the complex- ity of its natural formation process. In order to study the interaction mechanism between the cavities and the effect of the cavities on the mechanical behavior of rock,the uniaxial compression tests were conducted on the sandstone sam- ples with the different geometric arrangements of holes and the diameters of the side holes to obtain their strength,de- formation and fracture evolution laws. The result demonstrates that both the peak strength and elastic modulus of the samples show the trend of first decrease then increase with the increase of the angle. The minimum and maximum val- ues reach at α = 30° and α = 90°;the peak strength and elastic modulus show a gradually decrease with the increase of the diameter of the side hole. The damage form of the sandstone containing double circular cavities is affected by the angle and the side hole diameter,mainly in the three aspects of crack initiation forms of the samples,the fracturing be- havior of the central hole and the coalescence mode of the double circular cavities. The interaction between the central hole and the side hole gradually increases and then gradually decreases with the increase of the angle,the increase of the diameter of the side hole can also enhance the interaction between the central hole and the side hole,and this has been confirmed in the void coalescence.