Views: 1 Author: Site Editor Publish Time: 2020-10-27 Origin: Site
Trenchless directional drilling construction process-2
Pre-enlarging
After completing the pilot hole work, start the pre-expansion. According to the actual situation of the project and the technical requirements of the horizontal directional drilling crossing construction, the pipeline expansion is carried out in four stages. The reamers of φ200, φ300, φ400, φ500, and φ600 are selected in turn. The diameter of the pre-expanded hole is 1.5 times the diameter of the through pipe. After the optical cable pipeline traverses through the guide hole, it is directly towed with φ500 hole cleaner+rotary joint+returning head+φ457 steel pipe.
