Mechanism:

The mechanism by which split power works is shown in Fig. Cracks initiate from an inner surface of the hole where split power material is poured, being caused by tensile stress at a right angle with the compressive stress which occurs by the expansive stress of split power. The expansive stress of Split power continues even after the appearance of cracks, the cracks propagate and also new cracks initiate during the process. Usually, for a single hole, 2-4 cracks initiate and propagate. When a free surface exists, the crack, as shown in Fig. 2, is pushed apart mainly by the shear stress, and a secondary crack also arises from the bottom of the hole running toward the free surface.

Multiple holes are drilled adjacent to each other into the surface that is to be splited and split power is poured in those holes, when expands, the cracks from the hole propagate to connect with the neighboring holes