1.1 Directional drilling crossing construction will not hinder traffic, will not damage green space and vegetation, will not affect the normal life and work order of shops, hospitals, schools and residents, and solves the interference of traditional excavation construction on residents' lives, and the damage and adverse effects on traffic, environment and the foundation of surrounding buildings.

1.2 Modern crossing equipment has high crossing accuracy, easy to adjust the laying direction and burial depth, and the arc laying distance of pipelines is long, which can fully meet the design requirements of burial depth, and can make pipelines bypass underground obstacles.

1.3 The buried depth of urban pipelines is generally less than three meters. When crossing rivers, the buried depth is generally 9-18 meters under the riverbed. Therefore, horizontal directional drilling rigs are used for crossing, which has no impact on the surrounding environment, does not damage the landform and environment, and meets various environmental protection requirements.

1.4 When using horizontal directional drilling rigs for crossing construction, there is no water or underwater operation, which does not affect the navigation of rivers, does not damage the embankments and riverbed structures on both sides of rivers, and the construction is not restricted by seasons. It has the characteristics of short construction period, small number of personnel, high success rate, safe and reliable construction, etc.

1.5 Compared with other construction methods, the speed of entering and exiting the site is fast, the construction site can be flexibly adjusted, especially in urban construction, it can fully demonstrate its superiority, and the construction area is small, the project cost is low, and the construction speed is fast.

1.6 When crossing a large river, since the pipeline is buried 9-18 meters below the stratum, there is little oxygen and other corrosive substances inside the stratum, so it plays a natural anti-corrosion and heat preservation function, which can ensure that the pipeline runs longer.

1.7 Pre-expansion is to expand the hole back to the expected diameter step by step according to 1.3~1.5 times the diameter of the pipe size when the geological conditions and underground pipeline detection or survey are clear.