Key points of large diameter and short distance crossing of XCMG horizontal directional drilling rig
The main pipeline of Shangqiu central heating project adopts steel pipe and peripheral equipment.Φ1220*14mmΦ with 1370 * 17mm HDPE protective sleeve
In order to reduce the impact on road traffic during construction, Trenchless Directional Drilling is used in some sections. The geological conditions of the crossing area are mainly silt and silty clay. The crossing distance of this section is 400m, and the crossing obstacles are rivers and roads.
According to the pipeline specifications, formation conditions, construction distance and other factors, the use of 300 tons of horizontal directional drilling rig can meet the construction requirements. After investigation, XCMG xz3000 horizontal directional drilling rig was selected for construction.
|Drill Rods||Safe torque||Radius of curvature||weight|
|140*9600 mm||120 kN·m||110 m||425 kg|
|Guided drilling tool||Reamer|
|Inclined plate guide bit||140||Extruding reamer||Φ600mm~Φ1800mm|
Whole suspension is adopted when the pipeline is pulled back
Guidance: the construction depth is less than 15m, wireless guidance instrument can be used. The construction stratum is mainly composed of silt and silty clay, which is easy to drill and form holes. The inclined plate guided bit is used for drilling.
Reaming: in the reaming stage, the extruding reamer is used to expand the hole by stages. The span of each stage of reaming can be appropriately extended to 200 mm, and the final hole diameter is 1800mm.
Pull back: the pipe is suspended to prevent friction between the pipeline and the ground, and enter the borehole at a reasonable angle to reduce the drag back resistance.
Pipeline pull back succeeded
Guide construction should be carried out in strict accordance with the allowable bending radius of the pipeline to ensure that the bending state of the pipe in the hole is close to that of the drilling hole, so as to reduce the drag back resistance.
As far as possible, reduce the angle of soil entry and exit, especially the angle of excavation. If the excavation angle is too large, in order to ensure that the pipeline enters the hole at a reasonable angle, the lifting height of the pipeline or the excavation depth of the guide ditch will be increased.
A large amount of mud will be discharged from the hole in the process of pipeline pullback, so it is necessary to do a good job of mud collection to prevent environmental pollution.
Do a good job in the construction accident treatment plan, in order to facilitate the emergency rescue quickly after the accident, the earlier the rescue, the greater the possibility of success.