Jilian expressway Project-Key Project
Yong Lian tunnel
The total length of Yong Lian Tunnel is 5.108km, and the surrounding rock condition of the tunnel is extremely poor, with the surrounding rock ratio of Grade V and above as high as 70%. The geological conditions are particularly complex, and water inrush and mud outburst disasters occur frequently; The construction is extremely difficult, the landslides are frequent, the initial deformation is large (about 30cm/ day at most), and the safety risk is extremely high. Known as "rare tunnel in China, the first difficult tunnel in Jiangxi". At 9: 28 on May 6, 20 14, the left tunnel of Yong Lian Tunnel was officially connected.
Ao cheng he shui he bridge
The Heshui River Bridge in Aocheng consists of an approach bridge, an auxiliary hole and a main bridge, with a total length of 423 meters. Because the approach bridge spans the busy Yongdun Highway, the pile foundation is located on the cliff, and the other pier-free columns are all thin-walled hollow piers with a maximum height of about 50 meters. The main bridge has as many as 48 suspended concrete blocks, which is extremely difficult to construct.
Keeling expressway Project-Features
technology application
Builders in expressway, Jilin, divided the road construction into specific tasks with complicated procedures, formulated 60 standard construction methods and techniques, and implemented strict standard construction specifications and requirements in each link. Highway A5 is marked with beam-making yard, and beam-making is carried out in strict accordance with the construction methods and techniques formulated by the Project Office. Three methods are adopted: bellows positioning jig, flange plate jig and web plate jig. In terms of technology, three technologies, automatic spraying and curing technology, high-frequency vibrating concrete technology and intelligent tensioning technology, were introduced, and the beam and slab production changed from "small workshop processing" to "factory production". In addition, the project department 1 1 large, medium and small bridges of A2 bid section are constructed with self-compacting concrete.
In this project, special control measures are taken for the construction quality of tunnel entrance and initial support, and "zero excavation" of the tunnel is realized. According to the Standardized Construction Manual for Tunnel Engineering compiled by the Project Office, all tunnel openings are constructed by the method of "zero uphill entry", and five parties are required to be present during excavation, which not only maintains the stability of the tunnel vault, but also protects the surrounding ecology. During the construction of supporting steel arch spacing and shotcrete thickness at the initial stage of tunnel, the third party is entrusted to use radar scanning for geological detection; The water stop of the second lining of the tunnel is installed by burying, and the foot of the second lining trolley is changed to floor-standing, so that the appearance of the water stop and concrete is flat and round.
The project also cooperates with scientific research institutions and universities to actively carry out research on new technologies. In order to improve the durability and crack resistance of concrete, some bridges have carried out research on the subject of "construction and application of self-sealing concrete". In view of the common quality problems, research projects such as "Hinge joint construction technology and quality control method of assembled hollow slab beam" and "Research on application technology of expressway synchronous fiber-adding macadam sealing technology" have been carried out. For example, in the process of Yong Lian tunnel excavation, the Project Office and Shandong University jointly set up a technical research team, invited 4 professors and nearly 20 doctoral students to stay at the construction site to carry out scientific research, obtained three international leading technologies, such as "study on the mechanism of water inrush and mud outburst disaster", "study on grouting diffusion theory and blocking mechanism of water inrush" and "study on key technologies of water inrush and mud outburst disaster control", and developed three new technologies, such as "progressive subsection fine control grouting technology".
Architectural problems
1, the landform of the route changes greatly, the terrain fluctuates greatly, and the terrain of some sections is particularly complicated.
2. There are many exposed strata along the line, with developed fault structures and complex geological structures. There are many unfavorable geological phenomena in the route belt. Some road sections in the central and western regions are located in karst areas and weak interlayers such as coal. The regional engineering geological conditions are complex, and there are various unfavorable geological conditions such as karst ground collapse, goaf collapse, slope instability, landslide, underground river and collapse.
3. There are many viaducts, high slopes and tunnels in some sections (mainly in K30~K50), and the bridge-tunnel ratio exceeds 40%.
4. The route is greatly influenced by Heshui River, a tributary of Ganjiang River. The route crosses Heshui River for five times, which is affected by many factors, such as thin-walled high pier, large bridge span, steep terrain at the bridge site, difficulty in obtaining construction equipment and materials, and great construction difficulty.
5. Some sections pass through many environmentally sensitive areas such as villages, industrial parks and national key scenic spots, with beautiful natural environment, extremely fragile ecological environment, complicated local relations and arduous tasks of soil and water conservation and environmental protection;
6. The tunnel construction period is short and the task is heavy. In the long tunnel construction, four holes must be formed and constructed in turn. In addition, the distance between the long tunnel and the middle tunnel in this project is small. How to solve the problems of construction drainage, waste slag, ventilation, stability of surrounding rock between tunnels, development of construction working surface, pavement laying, construction safety and quality, etc.
The above is the introduction of Zhong Da Consulting Company of CBI to the project in expressway. For more information about expressways, please pay attention to the architectural knowledge column of Zhong Da Consulting.
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