2. Key points of the application of hydraulic rock drilling jumbos in tunnel construction 

2.1 Model selection of hydraulic rock drilling rigs

Hydraulic rock drilling rigs have undergone changes in different periods, from semi-hydraulic to fully computerized and fully intelligent. In the 1960s, only the trolley boom of the semi-hydraulic rock drilling rigs used this technology, and the rock drills still followed the pneumatic technology. In the mid-1970s, the fully hydraulic rock drilling rigs were launched on the market, and the rock drills applied hydraulic technology.

The selection of tunnel construction equipment requires a comprehensive consideration of the single-hole excavation length, cross-sectional area, soil state, etc., and also needs to meet the requirements of the construction method. Generally, for medium and large-section tunnels with a single-hole excavation length of more than three kilometers and relatively stable surrounding rock conditions, hydraulic rock drilling rigs will be selected for blasting drilling. If the single-hole excavation length is less than three kilometers, but the project needs to speed up the progress, hydraulic rock drilling rigs can also be used.

2.2 Analysis and control of tunnel over-excavation

The external insertion angle of the drilling rig drilling hole is larger than that of the pneumatic rock drill, which makes the surrounding holes deeper, which is the main factor causing the over-excavation to increase. This situation is due to the structure of the drilling rig, and it is difficult to avoid over-excavation at the technical level.

In addition, if the rock quality is poor in the construction section and the surrounding rock is damaged, after blasting, the blast hole traces are small, and the surface of the rock mass will fall off after blasting, resulting in over-excavation. The surrounding rock conditions of the tunnel cannot be stable, and this kind of over-excavation is inevitable, which needs to be analyzed and considered according to different surrounding rock conditions. Generally speaking, the more variable the surrounding rock conditions are, the more over-excavation will occur.

In addition to the above, human factors can also cause over-excavation. When marking the line, the surveyor may expand the excavation contour line outward by 5 to 10 cm out of the concept of "better to exceed than to lack", which greatly reduces the drilling rig's hole opening accuracy and ultimately causes the expansion of over-excavation; and the operator of the drilling rig does not control the external insertion angle accurately enough, which will also cause over-excavation during operation. There are many similar situations. Therefore, during construction, it is necessary to improve the management level, improve the technical level and professional quality of construction workers, strictly abide by reasonable construction guidelines, and reduce the over-excavation caused by human factors.

In order to achieve the improvement of blasting results and reduce the over-excavation phenomenon, it is necessary to deeply study and improve the blasting technology associated with the hydraulic drilling rig.

2.3 Analyze the focus of the hydraulic drilling rig from an economic perspective. From the perspective of the budget, the purchase amount, repair and maintenance costs and technical indicators of the hydraulic drilling rig should be collected and sorted out before construction, so as to facilitate the determination of the mechanical unit cost of the drilling rig and complete the economic analysis work.

The consumption of spare parts, drilling tools, water and electricity and other materials used in the construction of hydraulic drilling rigs should be counted in detail, and the classification and statistics should be strictly based on the surrounding rock type and excavation method, and the tunnel excavation quota should be compiled. Carrying out these basic work can help enterprises calculate costs and timely compile and revise industry construction quotas, which is of great significance.

Statistics on the progress of tunnel excavation by hydraulic drilling rigs and analyze cycle time. The construction of tunnels brings together production resources such as personnel, materials, equipment and construction technology in a certain time and space, which together affect the construction efficiency of tunnels. Engineering economic analysis should not only carefully analyze the time and rate required for the excavation operation of the rock drilling rig, but also study the tunnel construction efficiency generated by the comprehensive effect of different processes.

The economic analysis of the supporting technology of the rock drilling rig operation is equally important. First of all, it is necessary to clarify the resource allocation under the supporting conditions, ensure the construction quality and safety under the premise of ensuring labor protection, ensure the optimization of resource allocation, further reduce the economic gap between hydraulic rock drilling rigs and pneumatic rock drilling rigs in excavation supporting technology, and reflect the advantages of hydraulic rock drilling rigs.

3. How to give full play to the technical advantages of hydraulic rock drilling rigs

The technical advantages and technological advancement of hydraulic rock drilling rigs are objective, and it is necessary to better give play to their technical advantages. Pay attention to the following three points.

3.1 Hydraulic rock drilling rigs and pneumatic rock drills each have their own advantages. It is very important to reasonably allocate the supporting equipment of tunnel construction machinery. Only reasonable configuration can fully demonstrate performance and efficiency, and obtain the maximum economic benefits at a certain investment. In fact, hydraulic rock drills and pneumatic rock drills have different advantages in tunnel construction, and they also have corresponding use premises and requirements in different tunnel types. Not introducing hydraulic rock drills will cause some losses in terms of technology, and using all hydraulic rock drills meets domestic construction needs.

3.2 Reasonable preparation of economic indicators

Many construction units have a negative attitude towards the application of hydraulic rock drills due to economic benefits. If we blindly maintain the previous economic indicators, it will not help the application of hydraulic rock drills. The original quota is only suitable for new single-track and double-track tunnels and renovation and expansion projects not exceeding 6 kilometers, but there is a lack of quotas for tunnels exceeding 6 kilometers. Therefore, with the modernization of tunnel construction equipment today, the formulation of relevant content also needs to change.

3.3 Enhance the awareness of equipment use and management

From the technical and management aspects, when using and maintaining hydraulic rock drilling trolleys, we should also pay attention to these aspects: formulate reasonable and scientific mechanical unit costs; increase revenue and reduce expenditure from multiple angles to reduce construction costs; ensure correct and normal maintenance and maintenance to ensure the use status; ensure timely and correct procurement of accessories and timely supply; strengthen the professional skills and professional quality training of operators to ensure construction quality; integrate the drilling and blasting work of the trolley to speed up construction efficiency.