To investigate the effects of hole depths as well as the intervals of slurry grouting into outer holes and inner holes on the static crushing effect of thick concrete slabs, static crushing tests of seven thick concrete slab specimens were carried out. Boreholes were drilled perpendicular to the top surface of the thick concrete slab, and the longitudinal reinforcements on the upper part of the thick slab were cut off in two directions along the hole connecting line and its extension before crushing. Results showed that when the hole depth was less than 70% of the slab thickness, the cracks caused by the hardening and expansion of the slurry could not extend down to the bottom of the slab. When the hole depth increased from 70% to 90% of the slab thickness, the crushing effect was gradually improved, but the size of the minimum short edge and the size of the maximum long edge of the blocks after crushing were similar. When the hole depth was 80% of the slab thickness, the number of the blocks generated after crushing was the most. The slurry was first grouted into the outer holes and then into the inner holes after a certain time of hardening and expansion. Compared with the method of grouting all the boreholes at the same time, the crushing effect was improved, and the improvement in the external area was more obvious than that in the internal area. Besides, the number, the size of the minimum short edge, and the size of the maximum long edge of the blocks after crushing were similar. Based on the test results, the following suggestions are given: when crushing thick concrete slabs, the hole depth should be 80% of the slab thickness; it is better to first grout the slurry into the outer holes, and then the inner holes after the hardening and expansion of the slurry.