DEEP SOFTROCK GEOSTRESS TEST METHOD AND DEVICE BASED ON FLOW STRESS RECOVERY PRINCIPLE

摘要

A deep softrock geostress test method and device. The test device comprises a connecting rod (3), and two three-directional pressure boxes (1, 2) adjacently fixed on the connecting rod (3); the three-directional pressure boxes (1, 2) are provided with three mutually perpendicular working faces, the direction cosine between any two working faces of the two three-directional pressure boxes (1, 2) not equaling to 1; a normal pressure stress test device is installed on each working face of the two three-directional pressure boxes (1, 2); and the device is connected to a readout unit (5) outside a drilled hole via a data wire. The geostress measuring method comprises: drilling a hole and conveying the two three-directional pressure boxes (1, 2) to a test site; grouting the drilled hole and sealing the drilled hole after being fully grouted; and after the slurry is solidified and the data is stable, substituting the six pressure data measured by the two three-directional pressure boxes (1, 2) into a geostress test principle formula, so as to obtain the geostress at the test site. The present method can directly observe the stress value inside a surrounding rock, and can acquire the observation data over an extended period of time, thus facilitating study on the stability of the surrounding rock and the geostress of a softrock in the depth of a coal mine.