How to calculate the diameter of trenchless porous pipeline

According to the pipe diameter calculation formula, d = ((4v)/(π u)) 1/2. According to relevant data, trenchless refers to the laying and replacement by using various geotechnical drilling equipment and technical means under the condition of excavation of a very small part of the surface (generally referring to excavation of a small area at the entrance) by means of guiding and directional drilling.