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XCMG horizontal directional drilling multi pipeline construction — power pipeline crossing river!

July 16, 2020

XCMG horizontal directional drilling multi pipeline construction — power pipeline crossing river!

1.Project overview

directional drilling cross river

directional drilling cross river

The project is a high-pressure capacity expansion project of Shanghai Hutai Road. The directional drilling is used to cross the river with a span of 144m, and 21 pipelines with a diameter of Φ 200 mm are laid. The final reaming diameter is 1250mm.

 

Due to the existence of bridge piles in the river crossing the project, the pipeline crossing track needs to pass through the gap between the two bridge piles, so the space is limited, so it is not suitable to use multiple boreholes to lay pipelines, so the construction method of one hole 21 pipes is adopted.

2.Geological information

The stratum of crossing construction mainly consists of backfill layer, clay layer and silt. There are asphalt and cement subgrade left in the old Shanghai period 2 meters below the surface.

3.HDD machine model selection

one hole 21 pipes trenchless crossing

one hole 21 pipes trenchless crossing

 

XCMG XZ450 horizontal directional drilling rig is used for construction on site, and Golden Land GL700 wireless guidance instrument is selected as guidance instrument.

 

XCMG XZ450 horizontal directional drilling machine product highlights

Closed energy-saving circuit, hydraulic pilot control, load sensitive control and other advanced control technologies are adopted to save energy, reduce consumption and operate flexibly and comfortably.

The gear rack push-pull ensures stable and reliable transmission, and the spindle of the power head floats to improve the service life of the drill pipe thread.

The power amplifier head is selected to realize the function of doubling the pull back force of the power head to meet the special construction requirements.

The overall size of the fuselage is small, meeting the requirements of container transportation.

The wire controlled walking system ensures the safety of walking.

4.Accessories specification

Golden Land GL700 wireless guidance instrument

Golden Land GL700 wireless guidance instrument

Golden Land GL700 guidance

Golden Land GL700 guidance

Drill Rods
Drill rods safety torque radius  curvature weight
89*4500 mm 24 kN·m 80 m 95 kg
Guide drill Back reamer
Name Specification  name Specification
Inclined plate guide bit 89 Fluted reamer Φ600~Φ1250

 

5.Construction technology

XCMG XZ450 highlights

XCMG XZ450 highlights

inclined plate guiding bit supplier

inclined plate guiding bit supplier

Guidance: the maximum buried depth is 14m, positioning with wireless guiding instrument and drilling with ordinary inclined plate guiding bit.

Reaming: to meet the pull back of 21 Φ 200 mm PE pipes, the final hole is Φ 1250mm.

Pull back: 21 pipelines are towed back in groups, and the method of 8 + 5 + 5 + 3(When the first 8-hole pipe group is backstopped, the drill pipe connection and the pipe group can be backstopped together, so that after the completion of the backstopping, the drill pipe will naturally be in the underground hole, and the second 5-hole pipe group can be continued to be carried back, and so on. In this way, after the 8-hole pipe group is backstopped, the drill pipe does not need to be pushed out from the original hole, and then the remaining pipe group is backed back) is adopted. After the completion of a group of pullback, the drill pipe is pushed along the original hole from the soil entry point to the excavation point, and then the remaining pipeline is pulled back.

6.Case summary

(1) when the number of small diameter pipelines exceeds a certain number, it will also produce larger drag back resistance. The method of group backhauling can effectively improve the construction safety.

(2) It is suggested that the number of pipelines in each group should be reduced in order to improve the success rate of pull back.

(3) When pushing the drill pipe along the original hole, it is recommended to use a smooth guide head to avoid damaging the original hole wall and reduce the pushing resistance. It is strictly forbidden to use the reamer to push the drill pipe.

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