The Stress Analysis of Drilling Rod in Horizontal Directional Drilling during Trenchless Construction of Underground Pipelines

Due to its advantages, trenchless technology has been widely used all over the world during construction of underground pipelines, and horizontal directional drilling is the most popular trenchless technology. Because a drilling rod is subjected to the most complicated stress and the harshest working condition among all components in a horizontal directional drilling system, this paper lays emphasis on stress analysis of drilling rods. The finite element method and the computer software ANSYS are used to calculate the stress in the drilling rod. Also, the effects of torsional moment on the stress value and distribution are analyzed as well. The results of the above analyses give the location of the maximum Von Mises stress along the rod and indicate the relationship between maximum stress and the curvature radius of drilling rod. Generally speaking, the maximum stress usually occurs near the joints of the drilling rod, the rod stress decreases with an increase in curvature radius, and an increase in the torsional moment on the drilling rod can significantly increase the rod stress.