There are many kinds of drilling rigs for engineering exploration, such as core drilling rigs. According to the purpose of engineering investigation, the physical and mechanical properties of the rock and sand, as well as the drilling diameter, hole depth and drilling technology, the drilling rigs used are also different. In view of the fact that engineering drilling generally has strict requirements on sampling, it is required to take out undisturbed samples of sand or rock layers as the foundation of the project, and to avoid contamination of flushing fluid as much as possible, and to conduct directional coring when necessary, therefore, the drilling rig used must have the following characteristics.

1. Multi-function, widely used

There are many types of strata in our country, and the purpose of engineering investigation is different. Although the drilling is not deep, the complexity of drilling technology is no less than that of deep hole core drilling. For this reason, the drilling rig must have the characteristics of multi-function. At present, many engineering drilling rig products at home and abroad have various drilling functions such as rotation, impact, vibration, static pressure, etc. Some also have composite drilling functions such as impact rotary pipe drilling and rotary vibration eye pipe drilling. It is especially worthy of attention that hydraulic vibrator is attached with the drilling rig, which is very effective for drilling into sandy pebble formation. The vibrator uses a pair of eccentric wheels to rotate at a high speed in the opposite direction to generate centrifugal force, so that the vibrator can vibrate in the vertical direction, thereby generating an exciting force. By changing the rotation direction of the liquid motor and adjusting the hammering mechanism of the vibrator, the vibrator can be vibrated, hit up and hit down in both directions, which can be used for sinking the casing and pulling the casing.

2, large capacity, large reserve coefficient.

The medium-deep core drilling rig often takes the lifting capacity as the basic parameter of the drilling capacity of the drilling rig, while the engineering drilling rig is not. Because the drilling is shallow, the weight of the drilling tool is not enough, and the power is mainly used to overcome the huge resistance of the rotating soil layer and gravel layer. Such as rotary casing and pipe drilling method and the promising long spiral drilling method, both require a large torque. Therefore, the power of the engineering drilling rig with a hole depth of 30 to 50 meters is far greater than that of the core drilling rig with the same drilling depth capacity. It is understood that most of the drilling rigs used for engineering investigation in Hong Kong still use vertical shaft drilling rigs; one of the reasons is that they have a large capacity and are easy to deal with complex formations. Another special reason is that the area requires each hole to be drilled 5 meters below the bedrock to finish the hole. The bedrock here is all granite of grade 8~10, and most of them need diamond core drilling. Therefore, the CS-3 drilling rig with high and low grade (40~1000 r/min) and large through hole vertical shaft structure is very suitable for the engineering investigation and construction in this area.

3. Vehicle-mounted, with mast drill frame

Due to the shallow drilling, short construction period, frequent drilling rig movement, and flat urban construction roads, engineering drilling rigs have a variety of vehicle loading methods. The most common is a two-wheeled trailer mounted, such as G-ZA and GJD-50-type drilling rig; capacity is larger, can be used for drilling wells engineering drilling rig mounted on the car, such as G-2 and G-3-type drilling rig; also useful crawler mounted or mounted on a four-wheel tractor. These car loading methods have their own advantages and disadvantages. The car loading method is convenient for long-distance transportation. However, it is difficult to turn corners and move holes when the construction site is narrow and small. The melon belt car cannot be driven in the urban area. The four-wheel tractor is small and flexible, and can move on the construction site as well as on the road. It is a better car loading method. However, due to the lack of traction power, it is difficult to pull by manpower on the uneven construction site, which often causes the time to move the drilling rig to exceed the drilling time. Therefore, for the two-wheeled drilling rig with corresponding capacity, it is better to design the power self-mechanism.

Because the drilling is not deep and the drilling tools are not heavy, most of the drilling rigs are equipped with light mast drilling frames with a height of about 6 to 8 meters. Lie back on the rig for easy transportation. The landing of the mast depends on the special landing cylinder or the wire rope system of the winch.

4, high degree of mechanization, more ancillary equipment

In general engineering, the drilling footage is fast, sampling is good, the number of lifting drilling tools is large, and manual labor is frequent. Therefore, a pipe screwing machine, a shackle machine, a clamper, a pipe swinging device and a manipulator should be set up to reduce the number of operators and reduce manual labor. Sampling is an important part of engineering drilling, which directly affects the quality of the project. At present, sampling is generally carried out by pressing in and impact in our country. The method is simple and the sampling drilling tool is single. Sometimes, soil samples have to be knocked from the sampler manually, which greatly increases the auxiliary time. Therefore, the rig shall be accompanied by various borrow tools.

5, with a variety of testing methods

Engineering geological drilling in addition to sampling, but also a variety of tests, such as commonly used standard penetration test, dynamic penetration, static penetration, and so on. The standard penetration test is to use the elevator to lift the piercing heart and sleep again. After pulling to a certain height, the automatic decoupling device makes the heavy hammer fall freely to calculate the number of hammers penetrating into a certain depth. Many engineering drilling rigs can carry out static penetration test. As long as the drilling rig with hydraulic feed has ground anchor device and is equipped with side test instrument (resistance strain gauge or penetration automatic recorder), side test can be carried out. Some drilling rigs can carry out pressuretest, lateral well, lateral wave, etc.