Managing Large Soil Particles in HDD
Soil particles in HDD range from fine silts and clays to large boulders over 12 inches in diameter. Particles larger than 3 inches present high risks, as they can be nearly impossible to remove from the borehole due to the limitations in drilling mud's carrying capacity. When significant quantities of large particles like cobbles and boulders are present, it is essential to either avoid these areas or use strategies like conductor pipes to isolate the drilling path. Geotechnical reports that reveal such conditions may lead to decisions to alter the drilling path or even reconsider the feasibility of the HDD project altogether.