Rotary drilling rig construction method has the following advantages:
1. Broad adaptability
In hard soils, due to the limited weight of traditional drilling rigs, it is impossible to apply greater feed pressure to the drill bit, while rotary drilling rigs use power head devices and pressurization devices, the feed force of the power head and the drill pipe The self-weight and drilling ability are significantly enhanced, and its geotechnical drillability is: construction of soil and I-IV geology, and some of the V geology can also be constructed by rotary drilling rig construction method.
According to statistics, in the same formation, the hole-forming speed of rotary drilling rigs is 5 to 10 times that of traditional rigs.
2.Good environmental protection
At present, the traditional domestic drilling rigs mostly adopt the form of extended drill pipe and slag bucket slag. In the drilling process, mud circulation is used. The mud plays the role of lubrication, hole wall support, replacement and carrying of slag. Each unit volume of soil becomes more than five times the volume of mud to complete the drilling cycle. At the same time, more than twice the amount of slag is transported. This not only consumes a lot of energy, but also expands the contaminated area of the mud. Processing difficulty increases. The rotary drilling rig construction method uses a power head device and a pressurizing mechanism. Its working principle is to use a rotary drilling rig drill bit or a rotary bucket to directly dig the slag such as soil or gravel using a powerful torque, and then quickly lift out the hole. Dry mud construction can be achieved without the need for mud support. Even when mud protection is required in special formations, mud only supports the hole wall. The mud content during drilling is quite low. According to statistics, the amount of mud used in drilling is very low. It is only 1/10 to 1/2 of the soil volume, and the mud content of the slag for transportation is lower, so the pollution source is greatly reduced, the construction environment is improved, and the construction cost is reduced.
3. Improve the bearing capacity of cast-in-situ piles
Due to the special hole-forming technology of the rotary drilling rig, it only needs static pressure mud as the wall protection. The mud used is generally prepared with bentonite, pyrogenic alkali, cellulose, etc., and no thick mud skin will be formed on the hole wall. In addition, due to repeated reciprocating up and down of the rotary drilling rig drill bit, the hole wall has a high roughness and it is difficult to reduce the diameter. Compared with the traditional bored pile, the bearing capacity of the rotary bored pile is improved.