Author: Kovalev Dmitry Borisovich
Company: Moscow Polytechnic University; Department of “Techniques and technologies of mining and oil and gas production”
Country: Russian Federation
When constructing vertical shafts in difficult mining and geological conditions, it is often necessary to use special construction methods, in particular, the method of artificial freezing of rocks. To perform artificial freezing, special pipes with a threaded connection are used. However, when boring a hole through frozen rock, various emergencies can occur, caused by drilling and blasting operations or measuring the geomechanical state of the rock mass. The proposed design of the compensator will help to reduce the stress field during the explosion and ensure trouble-free borehole sinking. The compensator prevents the pipe from skewing and the development of cracks when the pipe breaks at the junction. The length of the expansion joint body is determined from the height of the threaded connection and the diameter of the freezing pipe. The seal is made of EPDM elastomer with full water resistance. The elastomer ring is pressed in with 6 circular fixing nozzles when installing the pipe. The compensator can withstand temperatures up to -35C, brine discharge pressure up to 120 kgf / cm2, axial displacement up to 30 mm at a depth of more than 400 m.
This design provides shielding of the threaded connection from the direct shock wave during blasting operations.