Deep softrock geostress test method and device based on flow stress recovery principle

摘要

Abstract The invention discloses a method and a device for testing a geo-stress of a deep soft rock. The device comprises a connecting rod; two three-direction pressure boxes are adjacently fixed on the connecting rod; the three-direction pressure box is provided with three vertical working surfaces; a direction cosine of any two working surfaces among the two three-direction pressure boxes is not 1; a device for measuring a normal pressure stress is mounted on each working surface of the two three-direction pressure boxes; and the device is connected with a reading instrument outside a drilling hole through a data wire. The geo-stress testing method comprises the following steps of: sending the two three-direction pressure boxes to a test point after drilling; grouting the drilling hole and sealing the drilling hole after the drilling hole is entirely filled; and after grout is solidified, and substituting six pressure data measured by the two three-direction pressure boxes into a geo-stress testing principle formula after the data is stable, so asto obtain the geo-stress at the test position. With the adoption of the method, a stress value inside surrounding rocks can be directly observed, and observation data can be obtained for a long time. Therefore, the method and device provided by the invention are good for research on the geo-stress of soft rocks in a deep coal mine and the stability of a surrounding rock.