Special safety construction of a variable section cast-in-place box girder on 104 national highway programme
The contract section x of the reconstruction project of the xxxx xxxx section of 104 national highway is located in Tongyu Street - xx Street, Luqiao District, Taizhou City, with a total length of 4.101km. It is constructed according to the technical standards of first-class highway, with a design speed of 80km/h, a separated subgrade width of 15.25m, and xx viaduct as the main part of the project, with a single bridge deck width of 13.25m, Xx viaduct crosses the hospital road (Class I highway), and the cast-in-place box girder C50 concrete double width one joint is 2 × 1260m3. The engineering geology along the line belongs to the coastal facies siltation plain. The shallow stratum is of marine deposit origin of 0~2.2m, which is clay crust layer, with Q34 on the upper part, Q24 and Q14 are the stratigraphic facies of coastal facies. The lithology is mainly mucky soil and clay, with a thickness of about 5~30m. The mucky soil is characterized by high compressibility, large deformation and long consolidation time. The middle part is formed by Q3 alluvial marine facies and alluvial lacustrine facies. The lithology is mainly composed of clay, silty clay gravel, etc., which is yellowish brown grey grey, belonging to medium and high compressibility soil, The layer is about 20~30m thick. The lower part is Q3 alluvial and lacustrine facies clay, silty clay, round gravel containing silty clay, which is gray~greenish gray, belonging to medium~low compressibility soil, with a thickness of about 0~25m. According to engineering drilling and geological survey, there is no adverse geological structure in this area. The preparation in the early stage of construction is sufficient to meet the construction conditions. Meteorology over the years, the extreme maximum temperature is 40.80c, and the minimum temperature is -9.90c. From July to August, affected by typhoons, the wind is strong and the rainfall is large, which often causes disasters and property losses.
