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Safe Operation Rules for Horizontal Directional Drilling Rig

June 28, 2019

This standard specifies the general requirements for horizontal directional drilling operations, operating conditions, safety preparation before operation, and safe operation during and after operation. This standard is suitable for GT series horizontal directional drilling rigs.


  1. General requirements

1.1 The operator should be specially trained to familiarize with and master the performance, construction, use and maintenance methods of the horizontal directional drilling rig and associated equipment.

1.2 During the construction process, operators should wear insulated shoes and wear safety equipment such as safety helmets and insulating gloves. The positioning detection operator should wear a warning suit.

1.3 The size of the back-drilling hole smuggling is 1.2—1.5 times the diameter of the pipe to be piped. According to the soil condition, a suitable drilling fluid should be prepared.

1.4 A fence should be placed around the horizontal directional drilling machine. When the horizontal directional drilling rig is in use, when an emergency situation occurs, emergency treatment should be carried out in accordance with the relevant provisions of the operating procedures.

1.5 For projects crossing railways and highways, the relevant competent authorities should be contacted before construction. The construction of the vehicles should be considered and warning signs should be set up.

1.6 When the drill pipe is disassembled, the threaded oil should be applied to the threaded part of the drill pipe. After completion, maintenance should be carried out in accordance with the maintenance manual.


  1. Working conditions

2.1 There must be enough working space at both ends of the pipeline to be laid. When the ground pressure is less than the ground pressure, measures should be taken.

2.2 When working in foundation pits or cofferdams, the foundation pits or cofferdams should be supported and equipped with adequate drainage.

2.3 There should be adequate lighting at night construction.


  1. Safety preparation before work

3.1 It is necessary to survey various underground pipelines and facilities within the range of at least 100m outside the length of the pipeline in the horizontal direction of the laying pipeline and at least 300m on both sides of the vertical pipeline, such as sewage pipes, water pipes, high-voltage cables, communication cables, optical cables, and gas. Pipeline and civil air defense projects. The data of these underground pipelines and facilities can be confirmed on-site with the pipeline unit according to the archives of the relevant departments and the original signs on the site, and further verified and verified by the instrument. If necessary, the excavation verification should be performed on the part. Mark the location and orientation of all underground pipelines and facilities on the construction profile and plan, and mark them on the ground.

3.2 The geological data should be consulted to understand the types of stratum soil. The soil layer’s interstitiality, water content, water permeability, groundwater level, bedrock depth, sand and gravel are measured, and the survey results are marked on the construction section. When crossing a river, you need to understand the topography and shape of the river, the urgency of the water flow, and the shape of the bottom of the river bed.

3.3 When designing the guide hole, the utility should be avoided, and the safety distance to the original pipeline and the minimum bending radius of the drill pipe during the construction of the drill guide hole and the back-drill hole should be fully considered to ensure the safety of the construction.

3.4 Check the hydraulic system according to the instructions in the instruction manual. The hydraulic hose should not be damaged. Check if the wire ends of the electrical circuit are loose and the electrical components are damaged. Check if the various registration forms are displayed properly. Check if the emergency stop switch is working properly. Check if the transfer case is rotating normally.


  1. Safe operation in the work

4.1 No one should touch the drill pipe while the drill pipe is rotating. When the propulsion or rotational pressure is abrupt during the drilling process, the analysis should be stopped immediately and the cause identified. When there is no signal, the signal is unchanged, the signal is abrupt, the water and gas are not smooth, etc., the analysis should be stopped immediately and the cause should be identified.

4.2 Generally, the bit positioning is measured once every 1 meter distance.

4.3 When the drill is required, it should swing symmetrically at a small angle. When the drill pipe is loose during the propulsion process, it should be rotated several times before continuing to swing. When the drill bit is close to the discharge pipe, it should be slowly propelled and gradually reduce the displacement of water and gas.

4.4 During the back-drilling process, ensure that there is an appropriate amount of drilling fluid in the hole.

4.5 In the event of anomalies in the process of back-drilling and reaming, such as stuck drills, blockage of water and gas pipelines, sudden changes in rotation and back-drag pressure, changes in the ground and structures, immediately stop the inspection and analysis, and if necessary, excavate and inspect.

4.6 During the reaming and pipe laying process, the host operator cannot operate the horizontal directional drilling rig without obtaining an operation command.


  1. After drilling the guide hole, clean the drill bit and the probe in time, and take out the battery inside the probe.


  1. Operation of the machine during construction

6.1 Preparation before construction

6.1.1 Put the machine in the right position.

6.1.2 The water delivery pipe of the mud preparation system is connected to the mud pump interface at the rear of the machine.

6.1.3 Start the patrol of the machine, look around the machine or see if there are loose bolts, garbage accumulation, oil or coolant leaking, damaged or worn parts. Check hydraulic fluid, engine oil, coolant and diesel.

6.1.4 Fill the mud tank with clean water and mix the bentonite. (depending on geological conditions)

6.2 Drilling process steps

6.2.1 Installation of each drill pipe in place and guiding drill bit;

  1. Retract the power head to the end.
  2. Put the drill pipe up (Note: If it is manual, it should be raised by two or more people on the track), the front end of the swing clamp position, the rear end of the power head short circuit thread.
  3. Manipulating the control handle causes the power head to rotate forward and slowly move the power head forward. Until the drill rod rotates, it means that the power head reducer rod has been combined with the drill rod.
  4. Continue to rotate and advance the power head until the first drill rod passes completely through the clamp.
  5. Install the pilot bit onto the drill pipe.
  6. Open the mud pump and observe the drill after the mud is sprayed out.
  7. After drilling into the tail of the first drill pipe and reaching the jaw of the swing clamp, the swing clamp is operated to clamp the tail of the drill pipe.
  8. Close the mud pump and operate the power head to rotate in the opposite direction until the power head reducer rod is completely unscrewed.
  9. Retract the power head to the end.

6.2.2 Subsequent drilling process

  1. Repeat steps b through i.
  2. Rotate and propel the power head. Dip the oil on the thread at the head of the drill pipe. When the head of the drill pipe approaches the tail of the previous drill pipe, the propulsion speed should be slowed down. After the two drill pipe threads have begun to combine, stop propelling and continue to rotate. The ring stops the rotation when the thread is firmly bonded but does not completely engage, and then loosens the retaining clamp.
  3. Open the mud pump and continue drilling.

6.2.3 Back to the hole reaming process steps

  1. After the guide hole is completed, the reaming operation is started after the reaming head, the rotary joint and the connecting rod are attached to the unloading point.
  2. Open the mud pump, the power head is turning forward and dragging the force head.
  3. When the two drill pipe joints reach the middle position of the two clamps, the drag back is stopped.
  4. Operate the fixed clamp to clamp the drill rod.
  5. Turn off the mud pump. Operate the swing clamp to clamp and loosen the drill rod.
  6. Loosen the fixed clamp and the power head rotates in the opposite direction until the drill pipe thread is completely loosened and then pulled back a little further.
  7. The fixed clamp clamps the head of the main drill pipe, and the power head rotates in reverse for about one turn, so that the power head reducer and the drill pipe can be loosened.
  8. Loosen the retaining clamp.
  9. The counter-rotating power head completely loosens the power head reducing rod and the drill rod, removes the drill rod, and retracts the power head to the end.
  10. The power head is propelled until the power head reducing rod is stopped near the tail of the drill rod clamped by the swinging clamp and the threaded oil is applied to the power head reducing rod. Operate the power head forward and slowly push the force head to join the threads. Release the pendulum clamp when the threads are not fully engaged.
  11. Open the mud pump, the power head is turning forward and dragging the force head.


Note: The non-excavation operation requires professional knowledge and training to operate. The above description is only a brief introduction to the drilling and returning steps during construction. The specific construction steps and plans shall be determined according to the specific conditions of the construction. It is strictly forbidden to operate without trained non-professionals. Otherwise, the consequences are at your own risk.

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    Wuhan Yichao Technology Equipment Co., Ltd. is a professional supplier of horizontal directional drilling rigs. We are XCMG authorized distributor and has nearly 10 years of trenchless pipeline experience.


    Email: m13517277987@163.com

    Tel: 0086-18162684887

    Wechat/WhatsApp: 0086-18162684887/0086-13517277987

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