Horizontal directional drilling technology

Horizontal directional drilling technology
Using horizontal directional drilling crossing technology in pipeline crossing construction, digging the ground, can through the highway, railway, river, or even can pass under the buildings, is a kind of can safely and effectively for the construction method of environmental protection. Especially in environmental protection, municipal pipeline network reconstruction project and large pipeline crossing river engineering more show its unique advantage.
The working process of the horizontal directional drilling crossing technology is guide through the computer control and detection, to drill a pilot hole, the same as the design curve then guide hole enlargement, pull the product pipeline back to expand the pilot hole, with the construction process of pipeline crossing.Horizontal directional drilling and trenchless technology has been widely used in foreign countries, and also gradually spread in the country.1 horizontal directional drilling crossing construction technology for pipeline crossing using horizontal directional drilling construction, generally divided into two steps: the first step is to accurately as possible in accordance with the design curve of drill a pilot hole;The second step is to guide hole reaming, and the product line (typically, MPP, PVC pipes, PE cable casing, pipe, pipe, etc.) along the guide hole back to expand the pilot hole, the pipeline crossing work done.1.1 guide hole guide hole drilling is the key of the directional drilling, guide device adopt wireless or wired positioning system to determine the control to the scheme, mud and driller must pay attention to each link, the careful analysis of various parameters, cooperate with each other accords with a requirement to drill a pilot hole, drill pilot hole to contrast analysis of geological data and instrument parameters into a hole at any time, and always be each drill pipe guide hole record (thrust size, guide hole size, torque, etc.) to the difficulty of the operator to pay close attention to the change of pump pressure, torque, thrust.1.2 preliminary reaming after the completion of the guide hole, the drilling to expand to the appropriate diameter for finished product pipeline installation, this process is called reaming, usually, on the other side drill reamer is connected to the pipe, and then by the drill rotating dragged back into the guide hole, the guide hole enlargement, to a large number of mud pump into the hole at the same time, to ensure the integrity of drilling and not collapsed, and will be cutting the cuttings back to the ground.Guide hole completion, to unload in time after bit unearthed, fitted with a reamer for reaming.According to the geological condition and pipe diameter grading reaming, finally aperture D = 1.2 1.3 Dn (Dn for pipeline diameter).Reaming, adjust appropriately according to the design requirements when the mud displacement control back to the drag speed, smooth bore hole reaming in accordance with the design parameters, the operator to pay close attention to the pump pressure, the change of the torque and drag back, it is strictly prohibited to suppress pump, suppress drill, forced back to enlarge.Analysis, after the completion of reaming hole formation, again with a reamer hole cleaning when necessary.1.3 back to drag pipes bore hole has been completed, the finished pipe into the borehole.Piping prefabrication should be completed in the side opposite the rig.Reamer drill pipe at the other end is connected at one end by rotary joints from finished product line.Rotary joint can avoid product pipeline with reamer rotating, so as to ensure its smooth into the hole.Dragged back completed by drilling, this process also requires a lot of mud to cooperate, to drag process should be continued until the reamer and finished product pipeline from one side drill ground.2 the characteristics of the horizontal directional drilling construction 1) directional drilling crossing construction has not blocking traffic, won’t destroy green land, vegetation, will not affect people’s normal life and work order, solve the traditional excavation construction interference impact on the residents’ life.