Development of a pressure coring system for the investigation of deep underground exploration

To provide a more accurate evaluation of the scale of deep underground resources, a new pressure coring system was carefully developed and its strength and safety of the engineering were verified by theoretical analyses and numerical simulation. The designed pressure coring system can obtain cores with length of 3 m and diameter of 50 mm at 70 MPa. The results of the ball-drop operation experiment demonstrate that differential motion assembly can effectively cut a safety pin by applying a tensile force of 4852 N, and it can lift the core tube through the center pole to complete a series of mechanical actions to seal the pressure. Additionally, by maintaining pressures at 70 MPa for 30 min, the pressure sealing capacity of the system was proven. Furthermore, a core sample with a diameter of 50 mm was obtained through a core drilling experiment and the coring performance of the pressure coring system was verified. This study can not only enrich the existing onshore coring technology but also provide a theoretical guide and design criteria for the development of similar pressure coring systems to meet the demand for deeper underground exploration