What are the factors affecting tunnel construction?
In recent years, due to the acceleration of the internationalization process, the transportation industry has developed rapidly. Road construction is not only related to people’s livelihood, but also an important pillar to promote national economic growth. In order to promote regional economic development, many regions have overcome geographical restrictions to build highways, and tunnel engineering is an important construction link. Tunnel projects are often located in areas with very complex geographic environments, including geological conditions and topography, etc., which require tunnel engineering construction technology. As a large-scale project, tunnel engineering not only has many and complex construction techniques, but also has high requirements for professional technology. In particular, there are many influencing factors in the tunnel engineering environment, which will inevitably cause various quality problems in tunnel construction. In order to ensure the construction quality, it is very necessary to formulate supervision measures according to the actual needs of the tunnel project.
Features of tunnel construction
Concealment
Tunnel engineering is a concealed project, and the construction of tunnel engineering must also have the characteristics of concealment. During construction, there is often only one visible side, and other constructions are concealed, which will inevitably have many unforeseen conditions. Even if there are hidden dangers left during construction, it is difficult to find out in time and make judgments.
Dynamic
The environment where the tunnel project is located is often complex and changeable. During the construction, this change will inevitably produce various accidental factors, which will cause the construction design to be inconsistent with the construction site. This means that to design a tunnel project, it is necessary not only to conduct site surveys, but also to fully understand the local surrounding rock conditions, so that the tunnel lining trolley is dynamic, so that the initial design is convenient when the construction site conditions change. to modify.
Risk
The area where tunnel construction is located is often in harsh environmental conditions, and most of the construction is carried out in caves or underground. Even if the operation is carried out in the same environmental space, the technical requirements of each operation link will be different, including tunnel lining technology, support technology and ventilation technology, etc., which must be selected according to the actual needs of the construction to ensure that each construction The links are closely connected, which will inevitably make the construction environment cramped, and different construction technologies will interfere with each other, which will inevitably have risk factors. In particular, the geological conditions of the tunnel construction area are changeable, and the lack of stability will inevitably have risks, making the tunnel construction dangerous accidents at any time.
Influencing factors existing in tunnel construction
Human Factors
In tunnel construction, people are the most active factor and also the factor lacking stability. To effectively control the tunnel construction, it is necessary to analyze in detail the potential safety hazards in each link of the construction, and formulate targeted control measures to play a management role in the construction. The staff involved in the construction activities should control the basic work in the construction, and analyze various intervention forms based on this. As the constructors in the construction proceed from their personal interests and ignore the responsibilities they should perform in the work, there will be problems in the adjustment of construction management procedures, which will inevitably affect the quality of tunnel construction.
Hard factor
The rigid factors that affect tunnel construction include material factors and equipment factors throughout the entire tunnel construction process. An important measure of the quality of tunnel construction is the material. To ensure that construction materials comply with relevant regulations, it is necessary to consider various factors that affect material quality. These factors are often important influencing factors leading to material problems, as well as basic factors affecting the quality of tunnel engineering. In tunnel construction, construction equipment is indispensable and the main object of construction safety management. To control and manage construction equipment, it is necessary for construction personnel to pay attention to equipment inspection. However, because the construction personnel neglect the daily maintenance of the equipment, it will inevitably have a negative impact on the construction of the tunnel project.
Technical control measures
During tunnel construction, scientific and reasonable technical control measures are the key to ensuring construction quality. However, when entering specific operations, it will be affected by a variety of factors, making it difficult for technical control measures to function. This is usually reflected in changes in construction procedures or adjustments to construction procedures, which will inevitably cause adverse effects on subsequent construction . To do a good job of technical control in tunnel construction, it is necessary to analyze various influencing factors and propose scientific and effective intervention measures to make technical control time-effective.
Key points of supervision and control of tunnel construction
Supervision and control of excavation site
Tunnel construction will have problems with over-excavation and under-excavation at the excavation site. Supervisors should conduct excavation quality inspections in accordance with the content specified in the relevant technical specifications. For under-excavation, if the rock formation is complete, the strength and structure of the lining will not be disturbed. When the compressive strength of the rock exceeds 30 MPa, the under-excavation amplitude in individual places should be defined within 0.1 square meters, and the uplift should not exceed 5 meters. . Including the position of the vault of the tunnel less than 1 meter and the corners of the walls must not be under-excavated to avoid dangerous accidents. The over-excavation phenomenon has been clearly stipulated in the tunnel engineering construction technical specifications. Due to the different geological rings of the surrounding rock, there will be different requirements for over-excavation.
Supervision and Control of Anchor Shotcrete Support
In tunnel construction, the bolting and shotcrete support cannot be ignored. In the process of acceptance of the tunnel project, the supervisor shall formulate the acceptance method according to the actual situation of the tunnel construction and notify the construction party in advance. Acceptance is required for every construction link in tunnel construction, and follow-up work can only be carried out after the acceptance is qualified. In the acceptance of the construction quality of anchor rods, attention should be paid to checking the angled anchor rods. In the acceptance of grouting construction, the supervisor must attach great importance to this process, because this process is not only technically difficult, but also has strict requirements on the grouting procedure.
Supervision and control of shotcrete
If there are omissions in the process of spraying concrete during tunnel construction, not only cracks will occur, but even water seepage will occur, which will cause adverse effects on the construction. The supervisor shall strictly control the sprayed concrete construction and require the construction personnel to adopt advanced technical measures to ensure the quality of the tunnel project.
Supervision and control of invert
In tunnel construction, the invert is an important construction part, which is related to the stability of the entire tunnel. If there are quality problems in the invert construction, it will affect the stability of the superstructure, especially the junction between the wall corner and the invert. It needs to be cleaned up before entering the construction process to avoid impurity in this part. The arch is not strong and produces uneven settlement.
In summary, there are high requirements for construction technology in tunnel construction, mainly because tunnel construction is a hidden project, and it is difficult to find hidden quality problems. This requires the analysis of the possible influencing factors in the tunnel construction, the exploration of technical methods, and the adoption of supervision and control measures that conform to the actual construction to avoid quality problems during the construction and ensure the smooth construction of the tunnel construction.
