To prevent the problem of noise and vibration which occurs in rock excavation work using explosives or machinery, a hydraulic frature machine has been made on a trial basis. The machine was able to add a concentrated load in the pressure hole by a wedge in four directions perpendiularly for obtaining an effective fracture. Cement mortar was used as a homogeneous specimen, the fracture experiment was carried out using two types of machines. Then, the effective distance between the pressure hole and the empty hole was investigated by a field test. The effect of the wedge was investigated by an experiment. Using the results of the experiment, mechanical behavior around the pressure hole and the development of the cracks were simulated by using "Crack Analysis Method". Then, the results were compared with the results of the field tests and discussed.
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