abstract
Expressway, the national trunk line from Jingkou to Liugou in Lanzhou, is an important part of the national trunk line from Lianyungang to Horgos planned by the Ministry of Communications. It is also a highway transportation corridor where three national highways meet at the east exit of Lanzhou, and it is also a key project for the main skeleton construction of Gansu highway network. The construction of expressway in Liu Xian plays an extremely important role in relieving the congestion and busyness of the original highway transportation, giving full play to the role of Lanzhou as a central city and promoting the economic development and all-round social progress of the whole province.
Expressway, Liu Xian adopts the four-lane expressway standard, with a total width of 24.5 meters and a design speed of 80 km/h, which is fully interconnected, fully enclosed and controlled. The route starts from Shili, about 10Km east of Jiaokou, and passes through Jiaokou, Liangjiaping, Huangjiachuan, Tujia Bay, Gancaodian, Qingshui Post and Qingshui Post.
end time
1998 65438+ February.
reform
1. In the field investigation, the following new technologies were adopted for layout. Using total station, the survey and encryption of the first-class traverse and the lofting of the middle pile were carried out, and the large-scale worksite maps and topographic maps of 1: 500,1:kloc-0/000 and 1: 2000 were surveyed.
2. In the interior design, the culvert CAD software developed by technicians using Quick-Basic and AutoCAD programs under DOS platform is used to design the culvert as a whole, which realizes the automation of culvert design and greatly improves the work efficiency. This achievement won the Excellent QC Group Award of the Ministry of Communications in 1998. After continuous upgrading, it is still used in culvert design.
3. In the design of interchange, the horizontal, vertical and horizontal design of interchange is carried out by using Incad interchange software. In addition, Autocad, Word and Excel are widely used in the design, drawing and tabulation of bridges and culverts, roads, interchanges and tunnels. Greatly accelerated the design efficiency and improved the design quality.
4. In geological exploration, the combination of geophysical exploration, seismic exploration and drilling improves the exploration accuracy. The exploration scope is expanded and accurate and reliable geological data are provided for the design.
5. Roadbed excavation slopes are all protected and reinforced by engineering measures, and shotcrete with low cost and convenient construction is used for high red mudstone slopes above Grade II; Embankment fill slopes are all protected by arch skeleton, rhombic grid and hollow precast slab combined with grass planting. In pavement design, the anti-sliding surface layer and stone matrix asphalt surface layer of asphalt concrete filled with TF polyester fiber were tested. For the pavement design of high fill section, glass fiber mesh is laid between the surface layer and the base layer to prevent the damage of subgrade reflection cracks to the pavement.
6. There are more than 20 dams on the expressway in Liu Chan, with the highest exceeding 50 meters. Using loess filler, the slope is reinforced with geogrid to prevent lateral deformation; Lay double-layer waterproof cloth on the water surface to prevent the water in the dam from scouring the subgrade; Measures such as subgrade construction and impact rolling ensure the compactness of subgrade. Its design and construction have accumulated valuable experience for the design of high embankment of high-grade highway in loess area.
7. There are 20 large and medium-sized bridges in Liu Chan and expressway. Except for the 50-meter simply supported T-beam, the remaining 19 superstructures all adopt the structural continuous system. The continuous curved box girder with a span of 50m was constructed in incremental launching method for the first time in our province.
8. Tujiawan Tunnel in expressway, Liu Chan is a loess tunnel. According to the characteristics of loess, such as collapsibility, looseness, air raid and poor stability, the design method of pre-strengthening the soil in front of the entrance with multiple anchors is adopted in tunnel design to improve the stability of surrounding rock and ensure the safety of tunnel. It has accumulated valuable experience for the design and construction of tunnels in loess soft soil areas.
9. The culvert design on the high-fill embankment adopts the construction scheme of dynamic compaction of the base, preloading first, and then excavation, so as to ensure that the compactness of backfill at the back of culvert abutment is consistent with that of subgrade. When designing the culvert, the whole foundation is set, and the camber is set along the culvert axis to prevent the influence of subgrade settlement on the structure.
10. For the treatment of collapsible loess and karst caves, the measures of dynamic compaction and impact rolling are adopted to eliminate the collapsibility of loess in a certain range, and the treatment methods of digging, filling and plugging are adopted for loess karst caves; Engineering measures such as replacement, riprap and siltation are adopted in soft foundation area.
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12, maurer expansion joint is used for all large and medium-sized bridges in expressway, Liu Chan, and TST seamless expansion joint is used for small bridges, which eliminates bump at the bridge head.
13. While completing the production task, the design institute actively carried out QC activities in combination with production practice and management. Among them, the QC achievement of "Design of High Fill Culvert in Loess Area" won the second prize of excellent achievement of Gansu Provincial Construction Committee. Draw the general plan of high fill culvert. It is a new breakthrough to solve the design of expressway culvert with high fill in loess area. By studying the properties of loess and the characteristics and functions of culverts, we have accumulated valuable experience for dealing with expressway in similar loess areas in the future.
14. Through the investigation and design of expressway, Liu Liu, the designers have a comprehensive understanding of the characteristics, functions and design of expressway for the first time, especially the design of high fill embankment, dam embankment, loess cave and long tunnel, and gained more successful experience. It not only improves the professional level and quality of designers, but also broadens their thinking and stimulates their enthusiasm. It is a new breakthrough and turning point in design, and provides a strong foundation for designing expressway in loess areas and various topographic and geological conditions in the future.
Winning record
The construction drawing design of expressway, Liu Xian won the second prize of highway engineering design of the Ministry of Communications in 2006 and the second prize of excellent engineering design of Gansu Province.
The above is the introduction of Zhong Da Consulting on Liu Xian Expressway. For more information about expressways, please pay attention to the architectural knowledge column of Zhong Da Consulting.
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